SPACE NEWS
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SPACE NEWS 07
--within the Solar System
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. . See also: "The Drake Equation" on the likelihood of life elsewhere.
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. . Click here for the clearest explanation I've found on dark energy & the expansion of the universe. (eXit to return)
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See Here's our page on just the Space-Elevator concept.
Regardless of when Hubble stops being scientifically useful, it will remain safely in orbit until at least 2013.
The Mars Foundation's hope for humanity's future on Mars is neatly summed up by their slogan: "To arrive, survive and thrive!" Mars Foundation: http://www.marshome.org/
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Dec 29, 07: The chance of a football field-sized planetisimal plowing into Mars next month has been increased to 4%, scientists said, after analyzing archival data. Though still a long shot, some researchers are hoping for a cosmic smash. "Usually when an planetisimal is headed toward Earth, I'm not rooting for an impact."
. . Scientists said last week there was a 1-in-75 chance the planetisimal could hit Mars on Jan. 30. The planetisimal poses no threat to Earth and is closing in on the Red Planet at 27,900 mph. Should a collision occur, it would likely blast a half-mile-wide crater north of where the rover Opportunity has been exploring since 2004. The impact could release energy similar to the 1908 Tunguska object that exploded over remote central Siberia and wiped out 60 million trees.
Dec 24, 07: The Oort cloud is a theoretical cloud of icy rocks roughly 7.5 trillion km from the sun thought to be the source of long-period comets —-that is, ones that take more than a few centuries to complete their orbits. It was once thought the original home of short-period comets as well, until calculations suggested that was impossible.
. . About 20 years ago, the Kuiper belt roughly 7.5 billion km from the sun was then proposed to be the home of short-period comets. "But measurements taken in the last few years raise some doubts about that", Jewitt explained. "Maybe there are other reservoirs of comets yet to be discovered."
. . Comets were long thought to be primordial relics, pristine leftovers from the protoplanetary disk that once surrounded the newborn sun. As such, it was supposed they might hold secrets untouched for billions of years regarding the birth of the Solar System.
. . Increasingly, however, it looks as if the comets we see are anything but unspoiled. Instead, "there is good evidence that many of them are nearly burned-out hulks, with neither the size, mass, shape nor spin they might have had before entering the Solar System", Jewitt said. Still, "since comets are icy, they're not entirely cooked, and we may learn a lot regarding the formation of the solar system from chemicals trapped in their ice", he added.
. . As the Solar System formed, calculations predict the gravitational pull of the planets would have scattered 90 to 99% of all comets that once orbited the sun away toward the stars, never to be seen again. "If every star does that, you would expect some of their comets to come toward us, but no such object has ever been seen", Jewitt said.
. . Still, as astronomical telescopes and techniques improve, Jewitt remains optimistic that such interstellar comets will be detected fairly soon. These comets would prove quite distinctive, zipping at great speeds and following trajectories completely unlike the orbits our comets follow.
Dec 21, 07: Brigham Young researcher Jani Radebaugh recently discovered 2,000 meter tall mountains on Saturn's moon Titan. The finding supports the idea that Titan has "some of the most earthlike processes of any celestial body in the Solar System." Radebaugh was analyzing NASA Cassini radar data in collaboration with the team that discovered sand dunes and methane lakes on Titan. The mountains are thought to be made of water ice.
Dec 20, 07: Mars could be in for an planetisimal hit. A newly discovered hunk of space rock has a 1 in 75 chance of slamming into the Red Planet on Jan. 30, scientists said.
. . Known as 2007 WD5, was discovered in late November and is similar in size to an object that hit remote central Siberia in 1908, unleashing energy equivalent to a 15-megaton nuclear bomb and wiping out 60 million trees.
. . Scientists tracking it, currently halfway between Earth and Mars, initially put the odds of impact at 1 in 350 but increased the chances this week. Scientists expect the odds to diminish again early next month after getting new observations of the planetisimal's orbit, Chesley said.
. . If the planetisimal does smash into Mars, it will probably hit near the equator close to where the rover Opportunity has been exploring the Martian plains since 2004. The robot is not in danger because it lies outside the impact zone. Speeding at 12kps, a collision would carve a hole the size of the famed Meteor Crater in Arizona.
Dec 20, 07: Researchers now suggest that ancient volcanoes could have released sulfur that warmed up the red planet enough for liquid water oceans in the early days of Mars. These findings might also shed insight on the young Earth, including the origins of life.
. . Scientists have often proposed the red planet was enveloped during its youth in an atmosphere rich in CO2. However, past findings suggest "that no amount of CO2 on its own can get early Mars above the freezing point of water", said Harvard U planetary geochemist Itay Halevy. Also, an atmosphere rich in CO2 would have led to massive deposits of limestone and other carbonate rocks littering the surface of Mars. The absence of such rocks has been a major puzzle.
. . Now Halevy and his colleagues propose in the Dec. 21 issue of the journal Science that volcanic gases loaded with sulfur could help solve both the puzzle of the missing rocks and the mystery of how Mars got warm enough for oceans.
. . The surface of Mars contains much higher levels of sulfur than Earth. This came from volcanoes that once erupted on the red planet. Compounds such as sulfur dioxide and hydrogen sulfide in volcanic gases could have acidified the ancient oceans of Mars enough to prevent the formation of carbonates, thus explaining their absence on the surface, Halevy said. In addition, sulfur dioxide is a potent greenhouse gas. If the atmosphere of early Mars was a hundredth or even a thousandth of a percent sulfur dioxide, that might have been enough to warm the red planet up for oceans.
Dec 19, 07: A probable active glacier has been identified for the first time on Mars. Ancient glaciers, many millions of years old, have been seen before on the Red Planet, but these ones may only be several thousand years old --between Mars' rugged southern highlands and the flat northern lowlands. This is found in very few places on the Red Planet because as soon ice is exposed to the Martian environment, it sublimates.
. . Dr Neukum said glacial features would be prime locations for robotic rovers to look for evidence of life on Mars. If microbes survive deep below Mars, they could be transported to the surface by water gushing up from deep underground.
Dec 19, 07: The infamous Tunguska explosion, which mysteriously leveled an area of Siberian forest nearly the size of Tokyo a century ago, might have been caused by an impacting planetisimal far smaller than previously thought.
. . The fact that a relatively small planetisimal could still cause such a massive explosion suggests "we should be making more efforts at detecting the smaller ones than we have till now", said researcher Mark Boslough, a physicist at Sandia.
. . The explosion on June 30, 1908, flattened some 2,000 square km of Siberian forest. Scientists calculated the Tunguska explosion could have been roughly as strong as 10 to 20 megatons of TNT —-1,000 times more powerful than the atom bomb dropped on Hiroshima.
. . In the last decade, researchers have conjectured the event was triggered by an planetisimal exploding in Earth's atmosphere that was roughly 30 meters and 560,000 metric tons in mass —-more than 10 times that of the Titanic. The space rock is thought to have blown up above the surface, only fragments possibly striking the ground.
. . Now new supercomputer simulations suggest "the planetisimal that caused the extensive damage was much smaller than we had thought", Boslough said. Specifically, he and his colleagues say it would have been a factor of three or four smaller in mass and perhaps 20 meters in diameter.
. . The simulations detail how an planetisimal that explodes as it runs into Earth's atmosphere will generate a supersonic jet of expanding superheated gas. This fireball would have caused blast waves that were stronger at the surface than previously thought. What scientists had thought to be an explosion between 10 and 20 megatons was more likely only three to five megatons, he explained.
Dec 18, 07: Four billion years ago, Uranus and Neptune switched places during a gentle ride out to their current orbits. That's the conclusion of Steve Desch, an astrophysicist at Arizona State U, who thinks that all of the gas giant planets took shape twice as close to the sun as they are at present. His work could cut out much of the mystery of how our "impossible" solar system formed.
. . The Solar System is 4.6 billion years old. The formation of rocky planets, from collisions between ever-larger objects, is a fairly rock-solid theory. But how the outer giants developed remains an open question. "Models predicted [Jupiter] would take many millions of years for it to form, and billions of years for Uranus and Neptune, but our solar system isn't that old", Desch said. "Having a denser disk of gas bunched up around the sun could explain the two planets' formations, but only if they switched places."
. . Neptune is currently the most distant planet from the sun at 4.5 billion km —-sorry Pluto, you no longer count. At 3 billion km away, Uranus is the second most-distant planet.
. . Most theories say planets slowly built up from a disk of gas and dust that once reached out to Neptune's current orbit. Turns out that's too spread-out to explain the formation of our solar system. To make our solar system work, Desch elaborated on the "Nice" model of planet formation that debuted in 2005. That theory suggests gassy planets formed about twice as close to the sun as they are now —-which means our dusty solar nebula would have been four to 10 times denser than most models predict.
. . "My colleagues seem pretty shocked by my paper, but they've found nothing wrong with it", Desch said. "Basically, I'm saying we have it all backwards: Planet-forming material had to have drifted outward, not in towards the sun."
. . Something pulled them outwards into their current orbits. Subtle gravitational "tugs" from passing comets, he said, could have done the trick over billions of years. "When I graphed out the data, it was almost spooky", he said of the disk density curve. "You hardly ever get data to fall into such a smooth predictive curve like that, but it did."
Dec 17, 07: An ocean is not the source of the jets emanating from Saturn's moon Enceladus, a new study concludes. The research questions the moon's promise as a target in the search for life beyond Earth and has stirred controversy among scientists who dispute its conclusions.
. . A chemical analysis of Enceladus, led by U of Colorado planetary scientist Nick Schneider, failed to detect sodium, an element scientists say should be in a body of water that has had billions of years of contact with rock.
. . "If you have a long-lived ocean, it's going to have salt in it", said Dr Schneider. Spectral analysis with the Keck Telescope found no sodium in the plumes or in the vapor that's in orbit around the moon. The source of the plumes is "very, very pure water", Dr Schneider concluded, and proposed clean ice, melt water or clathrates --a crystal of water, CO2 and ammonia --as alternative sources.
. . The fountains on Enceladus tantalize scientists by suggesting an ocean beneath the moon's icy crust. An ancient sea is the best bet for where life might evolve off Earth, scientists say.
. . At stake is whether Saturn's moon could support alien life and is a worthy target for a Nasa exploratory mission to detect it. Such a mission to Enceladus is one of four currently under review for further development.
. . "There is tremendous dispute about his interpretation of the results", said Carolyn Porco, the Imaging Team leader on the Cassini spacecraft. The absence of detectable sodium might mean only that; it's not detectible, said Dr Porco. It could be in a solid form that eludes detection by this method, she said.
. . One way to hide sodium is to put it in a salt crystal that becomes the nucleus of a water particle. If a sodium atom were tied up in a solid form, the Keck Telescope would not detect it. It only detects liberated sodium atoms, he said.
. . A spacecraft that would fly through the spray might be designed to sample the water directly and run tests to detect the presence of alien microbes. The concept that eventually emerges in the process will launch no earlier than 2015.
Dec 17, 07: There are hundreds of thousands of planetisimals circling our sun, all so-called "minor planets" left over from the formation of the Solar System. Much about them remains mysterious.
. . Among the puzzles:
. . There should be far more planetisimals that resemble Vesta, the second largest body in the planetisimal belt. The outermost layers of Vesta are composed mostly of basaltic rock—the same kind that makes up much of Earth's crust—and theories of planetisimal formation suggest more than half of all planetisimals should be made largely of either basalt or another common mineral on Earth, olivine. However, roughly 99% of these predicted planetisimals are missing. Many of Vesta's siblings might have disappeared when Saturn and Jupiter shifted their orbits roughly 4 billion years ago, slinging them at Earth, Luna and the rest of the inner solar system." This scattering likely caused the series of devastating cosmic impacts dubbed the Late Heavy Bombardment.
. . Why is Vesta so bright? Vesta is the brightest planetisimal, its surface being roughly three times as bright as Earth's moon. Its unusual brightness suggests it might possess a strong magnetic field, which could help shield it from particles driven by the solar wind that would ordinarily dirty it.
. . The Dawn spacecraft is currently venturing to the largest bodies in the planetisimal belt —-Vesta and Ceres—- but it lacks a magnetometer to probe magnetic fields, meaning a future mission is needed to solve the mystery's of Vesta's brightness.
Dec 13, 07: Saturn's shimmering rings may be as old as the solar system, scientists said, debunking earlier theories that the rings were formed during the dinosaur age. Astronomers had thought Saturn's rings were cosmically young, likely born some 100 million years ago from leftovers of a meteoric collision with a moon, based on data by NASA's Voyager spacecraft in the 1970s.
. . However, new data from the orbiting international Cassini spacecraft suggest the rings existed as far back as 4.5 billion years ago, roughly the same time the sun and planets formed. The probe also found evidence that ring particles are constantly shattering and regrouping to form new rings.
Dec 13, 07: Astronomers have confirmed the existence of a lopsided "doughnut" of electrified plasma surrounding Saturn. The giant ring current, as the doughnut is called, was confirmed following analysis of recent Cassini spacecraft data. But the new information adds a twist to the electric phenomenon, which extends more than 1.2 million km into space: It rotates.
. . Don Mitchell, an astrophysicist at Johns Hopkins U, explained that most of Saturn's ring current plasma comes from its ice-spewing moon Enceladus. "Earth's ring current is made of upper atmosphere and solar wind particles, so it's mostly hydrogen", Mitchell said. "But Saturn's source is by and large Enceladus, which shoots out a whole lot of oxygen in the form of water."
. . Mitchell explained that sunlight zaps the water and turns it into charged particles called ions, which Saturn's magnetic field captures and turns into a tube of energized plasma. The pressure of the solar wind, however, smears the night-side half of the ring into a sheet of plasma that continuously drifts into space.
Dec 11, 07: NASA scientists have discovered what might form some of the weirdest landscapes on Mars, winding channels carved into the Martian surface that scientists have dubbed "spiders," "lace" and "lizard skin."
The unusual landscape features form in an area of Mars' south pole called cryptic terrain because it once defied explanation.
. . But new observations from NASA's Mars Reconnaissance Orbiter bolster theories that the intricate patterns may be sculpted by springtime outbursts of carbon dioxide gas from underneath the frozen-carbon dioxide polar ice cap.
. . During the southern hemisphere winter, some of the carbon dioxide in the planet's atmosphere freezes to form a translucent ice cap made of the gas. Come spring, the sun's rays penetrate this layer of ice and begin to warm the red-rock surface underneath. "The sun passes through the ice and warms up the surface because the surface is dark and absorbs the sunlight." The warm surface then heats the ice layer from the bottom up, causing carbon dioxide gas to sublimate.
. . As the gas accumulates and its pressure increases, it seeks out weak spots in the ice and bursts forth, spewing carbon dioxide gas back into the Martian atmosphere. The gas carries some of the dust from the surface along with it, which then settles into "fans" on top of the ice. "It's a process unlike anything we have on Earth", Hansen said.
Dec 11, 07: As if scanning the moon's surface for impact blemishes were not enough, NASA now plans to visualize its internal imperfections to solve longstanding mysteries about the moon's insides. GRAIL beat out 23 elaborate competitors. NASA selected the Gravity Recovery and Interior Laboratory (GRAIL) mission from two dozen proposals. GRAIL's twin spacecraft are slated to launch around Sept. 6, 2011.
. . Scientists hope to use the data to pick apart its insides from crust to core, much like a medical X-ray that shows the insides of a person.
. . NASA previously launched a mission to map Earth's gravitational fields, called GRACE—the Gravity Recovery and Climate Experiment. Over the years, it measured minute differences in gravitational pull at different points around our planet, revealing glacial melt, migrating magma and tectonic plate movement, among other curiosities.
. . Similarly, GRAIL will measure gravity at different points around the moon, which should reveal any gravity differences as slight as 1 million times weaker than the Earth's overall gravity.
. . The Lunar Reconnaissance Orbiter (LRO), set to launch in 2008, will precede GRAIL's spaceshot. LRO will scan the moon's pockmarked surface for future robotic and human landing sites and will be accompanied by another spacecraft, called the Lunar Crater Observation and Sensing Satellite (LCROSS) mission—which will impact the lunar south pole to search for polar water.
Dec 11, 07: Nasa says its robot rover Spirit has made one of its most significant discoveries on the surface of Mars. Scientists believe a patch of ground disturbed by the vehicle shows evidence of a past environment that would have been perfect for microbial life. The deposits were probably produced when hot spring water or steam came into contact with volcanic rocks. On Earth, these are locations that tend to teem with bacteria.
. . It has been described as a fortuitous discovery. Spirit has been driving with a broken wheel that constantly digs a trough as the vehicle trundles across the Martian landscape. In May this year, scientists working on the mission noticed the churned-up soil had a much brighter appearance than usual.
. . Further investigation revealed it to be extremely rich in silica --the main ingredient of window glass-- and Spirit was commanded to examine the ground and nearby rocks in detail for extra clues.
. . The researchers have now concluded that the bright material must have been produced in one of two ways. One hypothesis is that Spirit is seeing hot-spring deposits produced when water dissolves silica at one location and then dumps it in another. The classic example is a geyser.
. . The other idea being pursued by the rover team is that they have stumbled across a fumarole, where acidic steam rises through cracks in rocks and strips them of all of their mineral components, apart from silica.
. . "The important thing is that whether it is one hypothesis or the other, the implications for the former habitability of Mars are pretty much the same", Professor Squyres explained.
. . Future missions will search for signs of chemical traces that could have been left by life. "One of the great things about these deposits is that not only does the hot water provide an environment in which the microbes can thrive, but the precipitation of that silica entombs and preserves them. "So you can get wonderfully preserved microbial microfossils."
. . Their designed mission lives were 90 days. Spirit has been on station for 1,400 days.
Dec 11, 07: Some hardy Earth bacteria could survive as hitchhikers clinging to the outside of spacecraft, studies have shown. Now a set of experiments going up with space shuttle Atlantis to the International Space Station will test how exposure to the harshness of space might change bacteria during a simulated Mars mission.
Dec 6, 07: Observations by NASA's Cassini spacecraft revealed the Saturnian moons Atlas and Pan, each roughly 20 km from pole to pole, have massive ridges bulging from their equators some 6 to 10.5 km high, giving them the flying-saucer appearance.
. . In principle, fast rates of spin might have stretched Atlas and Pan out into such unusual shapes, just as tossing a disk of pizza d ough flattens it out. But neither moon whirls very quickly, each taking about 14 hours to complete a rotation.
Carolyn Porco, a planetary scientist at the Space Science Institute, suspected these peculiar moons could be formed mostly from Saturn's rings, rather than just from fragments produced in collisions of larger moons, as some have suggested. The location of the ridges lined up precisely with the rings of icy particles in which they were embedded.
. . After analyzing the shapes and densities of the moons, Porco's team now finds Pan and Atlas appear to be mostly light, porous, icy bodies, just like the particles making up the rings. Computer simulations suggest one-half to two-thirds of these bizarre moons are made of ring material, piled up on massive, dense fragments of bigger moons that disintegrated billions of years ago after catastrophic collisions with one another.
. . These findings could shed light on the behavior of "accretion disks" -—disks that build up as matter falls toward a gravitational pull.
Dec 6, 07: The solar wind, which whips off the sun and blows past Earth and through the solar system, is unleashed by powerful magnetic waves in electrically charged gas around the sun, scientists said. The mechanisms that cause the solar wind had baffled scientists for decades, but were revealed in observations by a Japanese satellite called Hinode orbiting Earth.
Dec 6, 07: The plains of solidified lava that give Luna its quirky human-like face as seen from Earth were created more than four billion years ago, according to a study.
. . Volcanoes were active on Luna's surface soon after it was formed, a new study suggests. Precision dating of a lunar rock that fell to Earth shows our satellite must have had lava erupting across its vast plains 4.35 billion years ago.
Dec 5, 07: Theorists have what they think is a good handle on how rocky planets like Earth form. Leftovers of star formation collide, stick together and eventually form a ball of rock.
. . However, the formation of gas giant planets is more mysterious. For starters, so many gas giants beyond our solar system have been found improbably close to their host stars -—in some cases with blistering effects and an unsustainable outflow of material-— that researchers figure they probably formed farther out and then migrated inward.
. . Such a scheme would have huge implications for the development of any planetary system, as a migrating giant (like Jupiter or bigger) would tend to gobble up aspiring Earths on the way in. And what's to stop the migrating worlds from getting too close and vaporizing altogether?
. . Among many questions about all this, one has just been answered: How close can a giant planet get to a star before its atmosphere becomes unstable and the planet is doomed to catastrophe?
. . Koskinen's team brought a virtual Jupiter closer and closer to the sun. "If you brought Jupiter inside the Earth's orbit, to 0.16AU, it would remain Jupiter-like, with a stable atmosphere", Koskinen said. "But if you brought it just a little bit closer to the sun, to 0.14AU, its atmosphere would suddenly start to expand, become unstable and escape."
. . Equally important in the research is what causes the sudden catastrophic loss of air. A giant planet is cooled by its own winds blowing around the planet. This helps keep the atmosphere stable. Another cool effect: An electrically-charged form of hydrogen called H3+ reflects solar radiation back to space. As the virtual Jupiter was brought closer to the sun, more H3+ was produced, bolstering this cooling mechanism.
. . "If you take a planet even slightly beyond this, molecular hydrogen becomes unstable and no more H3+ is produced. The self-regulating, 'thermostatic' effect then disintegrates and the atmosphere begins to heat up uncontrollably."
. . "This gives us an insight to the evolution of giant planets, which typically form as an ice core out in the cold depths of space before migrating in towards their host star over a period of several million years. Now we know that at some point, they all probably cross this point of no return and undergo a catastrophic breakdown."
Nov 29, 07: A private spaceflight firm is developing a new unmanned spacecraft in hopes of delivering cargo for NASA missions to the International Space Station (ISS).
Nov 28, 07: Nasa has released details of its strategy for sending a human crew to Mars within the next few decades. The US space agency envisages despatching a "minimal" crew on a 30-month round trip to the Red Planet in a 400,000kg (400 ton) spacecraft. The "Mars ship" would be assembled in low-Earth orbit using three to four Ares V rockets --the new heavy-lift launch vehicle that Nasa is developing.
. . Notionally despatched in February 2031, the mission's journey from Earth to Mars would take six to seven months in a spacecraft powered by an advanced cryogenic fuel propulsion system. Estimates of the cost of mounting a manned Mars mission vary enormously, from $20bn to $450bn. The details are highly subject to change, and may not represent the way Nasa eventually chooses to go to the Red Planet.
Nov 28, 07: Lightning crackles in the atmosphere of Earth's "evil twin" Venus, while the meager remnants of suspected bygone oceans continue to be whipped off the planet and lost to space, scientists said. They unveiled a series of findings from the European Space Agency's Venus Express.
. . At some point in their 4.5-billion-year histories, something went horribly wrong on Venus. The greenhouse effect ran amok, making Venus a hellish kiln --its surface hot and dry, its crushing atmosphere made up of CO2 permeated by clouds of sulfuric acid that cloak the planet.
. . Equipment aboard the spacecraft allowed scientists to observe how particles escape from the atmosphere. The dominant escaping ions, the scientists found, include oxygen and hydrogen in the ratio that corresponds to water, which may help to explain how Venus lost its original water to space.
. . Venus, unlike Earth, lacks a magnetic field to protect its atmosphere from the solar wind, the stream of electrically charged particles emitted by the Sun. Thus, the solar wind interacts directly with the upper atmosphere of Venus, causing Venus's atmosphere to lose its gases in the form of ionized particles.
. . Liquid water oceans may have been present on Venus as recently [!] as 1 billion to 3 billion years ago.
Nov 27, 07: Mars, now cooled into crusty sphere, once sizzled with oceans of magma for millions of years. New research suggests it was red-hot tens of millions of years longer than previously thought. Rare chunks of Martian rock flung to Earth as meteorites hint at an extended molten status, for which scientists think a thick, early atmosphere was responsible.
. . "Some type of insulating blanket, either as a rocky crust or a thick atmosphere, is needed as an insulator to have kept the Martian interior hot."
. . Nine Martian meteorites were examined. "They were delivered to Earth ... following impacts on Mars that exhumed them and launched them into space." Called shergottites, the rare meteorites were named after the first one that landed in Shergotty, India in 1865. Study co-author Vinciane Debaille, a planetary scientist at the Lunar and Planetary Institute in Houston, dated the rocks' radioactive metals to determine when the fiery entrails of early Mars formed them.
. . She explained that the oldest formed 35 million years after the solar system began to condense from ice and dust into large planets, about 4.567 billion years ago. The youngest formed about 110 million years after planets began to accrete.
. . Debaille and her colleagues think a global magma ocean existed in the final stages of Mars' formation, then slowly solidified over this time period. To slow that cooling, she thinks an atmospheric blanket once insulated the planet. "The primitive atmosphere was composed mostly of hydrogen left over from accretion. But [it] was removed, probably by impacts, about 100 million years after the planet formed."
Nov 26, 07: Colossal impacts in the outer reaches of the Solar System may have bowled over remote, frozen moons, leading to vast cracks across their surfaces, research now suggests.
. . Imagine a bowling ball as it rolls down an alley. It will often come to rest with its finger holes—where it has the least mass—resting on top, stabilizing itself. In much the same way, "if you carve a hole in a spinning planet, the planet will tilt over so that the hole ends up at the nearest pole. In the case of a planet, the hole is carved out by an planetisimal or comet impact."
. . Often, icy moons in the outer Solar System boast large impact craters. Now researchers calculate the greatest of these craters might have tilted two of Saturn's moons, Tethys and Rhea, and Uranus's moon Titania roughly 4 degrees, 7 degrees and 12 degrees, respectively.
. . If Pluto and Charon possess impact craters as large as those seen on Saturn's moons, they might have shifted 10 and 20 degrees, respectively, and perhaps "developed a global network of fractures", Nimmo added. This is a prediction that can be tested once the NASA's New Horizons spacecraft arrives in 2015.
. . "[Luna] probably underwent multiple reorientation episodes when it was being battered by impacts early in its history."
. . The new findings concerning the icy satellites may have failed to adequately consider the matter blown out by these impacts, said planetary scientist Jay Melosh at the U of Arizona at Tucson. After that debris settles back down around the rim of the crater, it could even out any instabilities, reducing any resulting tumbling by as much as a factor of five.
. . A huge crater near the south pole of Luna -—the Aitken basin—- may be large enough to have triggered a dramatic roll early in Luna's history, Melosh noted. "That one's big enough to count", he said.
Nov 15, 07: The European Space Agency (Esa) has drawn up its short-list of the best places to look for life on Mars. Esa will launch a mission called ExoMars in 2013 in which a robot rover will search the Martian surface for evidence of past or present life.
. . "Phyllosilicates are not just regions where we think water must have been. We also think they are places that helped reactions to take place. He added: "On the early Earth, all the primordial biochemistry took place in phyllosilicates as well. The other option is to look at evaporites (like sulphates)." Dr Parnell favors sending the rover to Meridiani Planum where both phyllosilicate and sulphate minerals can be found in abundance.
. . Nasa is studying a similar shortlist of six landing sites for its Mars Science Laboratory (MSL) mission, due to fly even sooner than ExoMars --in late 2009. He added that there is no chance of the US and Europe choosing the same landing site.
Nov 15, 07: A tiny comet that has delighted backyard astronomers in recent weeks after an unexpected eruption has now grown larger than the sun. The coma's diameter on Nov. 9 was 1.4 million km.
. . The comet's coma -—mostly microscopic particles—- shines by reflecting sunlight. Holmes is still visible to the naked eye as a fuzzy star anytime after dark, high in the northeast sky. "This amazing eruption of the comet is produced by dust ejected from a tiny solid nucleus made of ice and rock, only 3.6 km in diameter."
Nov 13, 07: The sand dunes of Mars are in no rush to move across the red planet's surface, new research shows. It can take up to 1,000 years for dunes to move just a few meters on Mars, largely due to the planet's apparent lack of moving surface water, weak winds and very thin atmosphere, said the study's author Eric Parteli. The atmosphere of Mars is 100 times less dense than that of Earth.
. . The scientists found that a small Martian sand dune about 1-meter tall would need wind speeds 120 kph to move appreciably. Since such winds are extremely rare on the red planet, occurring just a few times each decade, the dunes of Mars are confined to their glacial pace.
. . Dunes on Mars can reach heights of 6 meters and come in shapes ranging from crescents to stars, though similar sand dune formations are seen on Earth.
Nov 8, 07: A European spacecraft has used radar to probe one of the youngest and most mystifying deposits on Mars.
. . The European Space Agency's Mars Express orbiter studied the Medusae Fossae Formation (MFF), which straddles a divide between the highlands and lowlands near the Martian equator. MFF deposits have remained an enigma partly because they are "stealth" regions that give no radar echo from certain wavelengths of Earth-based radar. "The new data show that the MFF are massive deposits over 2.5 km thick in some places where MARSIS orbits pass over them."
. . Scientists have proposed a variety of scenarios about the origin and composition of the MFF deposits. They could be volcanic ash deposits, wind-blown materials eroded from other Martian rocks, or even ice-rich deposits that formed when the spin axis of the planet tilted over and made the equatorial region colder.
. . MARSIS revealed both the depth and electrical properties of the deposit layers, suggesting that the layers could be poorly packed, fluffy or dusty material. But scientists are puzzled over how material from wind-blown dust could be kilometers thick and not have compacted under the weight of overlying material.
. . Although the electrical properties resemble those of water ice layers, there is no other strong evidence for ice remaining at the Mars equator. The water vapor pressure on Mars is so low that any ice near the surface would quickly evaporate, leaving the mystery of the Medusae Fossae Formation for scientists to ponder.
Nov 8, 07: NASA penny-pinching risks are exposing humankind to a planetary catastrophe, if a big enough asteroid evades detection and slams into Earth, US lawmakers warned.
. . But the US space agency said the chances of a new "Near-Earth Object" (NEO) like the one that wiped out the dinosaurs were too remote to divert scarce resources. Scott Pace, head of program analysis and evaluation at NASA, said the agency could not do more to detect NEOs "given the constrained resources and the strategic objectives NASA already has been tasked with."
. . Lawmakers decried the threatened closure of a giant radio telescope in Puerto Rico run with NASA's assistance that is the world's foremost facility for tracking space objects.
. . NASA now only tracks NEOs larger than one km in diameter, which come near Earth only once every few hundred thousand years. "Extinction-class" objects measuring at least 10 km, such as the object that crashed into Mexico's Yucatan peninsula about 65 million years ago, would be rarer still.
Nov 7, 07: Germany hopes to put an unmanned space craft into the moon's orbit in the early part of the next decade, a senior German official said.
Oct 31, 07: An explosion on a distant comet, Holmes, was so big that the comet brightened by a factor of a million; and it can now be seen from the Northern Hemisphere with the naked eye. Holmes is currently moving away from the Sun, and is almost midway between the orbits of Mars and Jupiter.
. . It was a once in a lifetime event. "Although comets have been seen to undergo outbursts before, the scale of this dwarfed anything seen in the past century. From these images, we can see the ejecta moving away from the comet at 2,000km per hour. The total amount of material ejected is probably about 1% of the total mass of the comet.
. . It takes 6.9 years to orbit the Sun once. It made its closest approach to our star last May, passing by at some 300 million km.
Oct 29, 07: Small satellites could soon get a boost from a novel in-space propulsion system under development at the U.S. Defense Advanced Research Projects Agency (DARPA). Called the High Delta-V Experiment, or HiDVE for short, the program aims within the next year or so to complete a ground demonstration of an unconventional propulsion system that uses the heat of the sun to produce enough thrust to push a 10-15 kilogram satellite into a new orbit.
. . Typically, very small satellites have to make due with secondary launch opportunities and frequently are dropped off in non-optimal orbits. Since very small satellites more often than not are built without any meaningful propulsive capability, they must remain there.
. . U.S. Air Force Lt. Col. Fred Kennedy, DARPA's HiDVE program manager, believes that solar thermal propulsion, which uses the warmth of the sun to heat an onboard liquid such as water or ammonia to very high temperatures, and vent it through a nozzle can change that. "It's essentially a steam kettle", he said. "What you are trying to do is construct a very, very small, perhaps thimble-size, heat exchanger and flow a low molecular weight fluid through it – be it water, ammonia or methane – heat it up to very high temperatures, typically 2,000 to 3,000 degrees Celsius, exhaust it through a nozzle.
. . Solar electric propulsion, despite being highly efficient, is not a good solution for tiny satellites, Kennedy said, because they require more electrical power than small satellites can be expected to generate.
Oct 23, 07: A rock quarried on Orkney was blasted into space to find out if meteorites could carry primitive life from one planet to another. One theory being tested is whether life could have arrived on Earth from Mars.
. . U of Aberdeen experts had the rock attached to an unmanned Russian craft and found life would probably only survive in a large meteorite. Its the size of a bowler hat, it was then attached to the side of the European Space Agency's Foton M3 mission, which launched from Kazakhstan last month.
. . Professor John Parnell, chair in geology and petroleum geology at Aberdeen, studied what effect the heat of re-entry from space had on the rock, along with Dr Stephen Bowden. Orcadian rock was sellected, as it's hard and incorporates organics. However, he said any bigger and the meteorite would hit the ground so hard that it would vaporize.
Oct 23, 07: Enormous bubbles of plasma trapped within Earth's magnetic fields have been fully mapped for the first time. Scientists now think the bubbles of ionized gas, called convection cells, are strongly affected by pummeling from the sun's solar wind. Future observations of the cells could be used to monitor violent solar outbursts, such as solar flares and coronal mass ejections, which can harm satellites or astronauts in space.
. . Convection cells exist high above Earth's polar caps and are made of plasma, which is electron-stripped gas that is highly erratic. Earth's magnetosphere and atmosphere shelter the planet from high-energy solar particles, but the protective shells form an incomplete cocoon—so some of the radiation leaks in, is trapped and forms convection cells.
Oct 19, 07: A mission could be launched before the end of the next decade to put a balloon on Titan, the hazy Saturnian moon. The balloon is one of several ideas being considered by the European Space Agency as it sketches out where its science should be focused. Other proposals include an X-ray telescope that flies in two parts; and a sample-return mission to a planetisimal.
. . All the ideas will be subjected to further study; and are likely to evolve as international partners get involved. Eventually, two missions will be selected, one to fly no earlier than 2017 and the other no earlier than 2018.
. . Nasa found that no meaningful mission to the Saturnian system could be undertaken for less than $1bn (700,000 euros) and would in all events cost considerably more.
. . . The L-Class candidates include:
. . * Laplace: This mission would go to Jupiter and its moons. A key target of interest would be the icy moon Europa which is thought to harbour an ocean under its icy crust. The mission would deploy three orbiting platforms to perform coordinated observations of Europa, the Jovian satellites, Jupiter's magnetosphere and its atmosphere and interior.
. . * Tandem: The mission would explore both Titan and Enceladus, the other Saturnian moon currently fascinating scientists. The mission would carry two spacecraft - an orbiter and a carrier to deliver an instrument-carrying balloon and three probes on to Titan.
. . * Xeus: This next-generation telescope would study the X-ray Universe. It comes in two parts: a mirror satellite and a detector satellite which have to be flown in formation with extreme precision.
. . * Spica: The Japanese are proposing an L-Class mission which would launch a telescope to study the cosmos at far infrared wavelengths. If Europe became involved, it would bring expertise and technology developed for its own Herschel telescope due to launch next year.
. . L-Class will cost Esa something in the region of 650m euros; and medium (M-Class), is projected to cost the agency about 300m euros.
. . . The M-Class candidates include:
. . * Cross-scale: : A swarm of 12 spacecraft to make simultaneous measurements of plasma (charged gas) surrounding Earth.
. . * Marco Polo: : A sample-return mission to a near-Earth object. It would consist of a mother satellite which would carry a lander, sampling devices, re-entry capsule as well as instruments.
. . * Dune and Space: : These are two mission ideas before Esa that would tell us more about the mysterious "dark matter" and even stranger "dark energy" that seem to dominate our Universe but which have proven frustratingly difficult to explain with current observation technologies.
. . * Plato: A mission to find and study planets beyond our Solar System. It would be capable of observing rocky (similar to Earth) exoplanets around brighter and better characterised stars than its predecessors, such as the recently launched Corot mission.
At the end of the assessment process, it is likely Esa will select just one L-Class and one M-Class to take forward to full development and launch. One complicating factor is the desire to loft an observatory into space that can test a key prediction of Albert Einstein's Theory of General Relativity --by making a detection of gravitational waves.
. . Europe and the US are together developing a mission known as Lisa which would detect these "ripples" in the fabric of space-time --but it is proving an immense challenge from a technological standpoint.
Oct 17, 07: New research on Hawaiian volcanoes, combined with satellite imagery of Mars, suggests that three Martian volcanoes may only be dormant—not extinct. Instead of Mars' crust moving over stationary magma "hot spots", as occurs on Earth, researchers think the plumes travel. "Our research raises the possibility that the opposite happens on Mars; a plume might move beneath stationary crust."
. . Each of the volcanoes, located in the Tharsis region of Mars, is about 300 km across. The largest volcano on Earth, Mauna Loa, is only 97 km across.
Oct 16, 07: Jupiter's volcanic moon Io is veiled by a thin atmosphere, but how much its volcanoes and chunks of frozen gas contribute to its atmosphere has puzzled scientists for decades. The New Horizons spacecraft recently documented the moon's glowing aurora, however, giving researchers a chance to solve the atmospheric mystery.
. . Io is the most volcanically active object in the solar system. The moon's pockmarked and colorful appearance is not unlike a pepperoni pizza. "Io is volcanically active, and that volcanism ultimately is the source material for Io's sulfur-dioxide atmosphere." "But the relative contributions of volcanic plumes and sublimation of frosts deposited near the plumes have remained a question for almost 30 years."
. . Io's volcanoes spew out sulfur dioxide, which is a gas that stinks of freshly lit matches. During the night, the gas freezes into a solid, much like dry ice. About 1 to 3% of Io's dayside atmosphere, it turns out, is created by the volcanoes. The rest is generated from frozen sulfur dioxide turning directly into gas which, over eons, has accumulated on Io's surface.
Oct 16, 07: The mineral composition of a near-Earth planetisimal with a slight chance of striking our planet in 2036 has been determined for the first time. By analyzing sunlight reflected off its surface, scientists say the planetisimal Apophis is a "good match" for a rare type of stony meteorite known as a type LL chondrite. This group of space rocks represents just 7% of the known meteorites that fall to Earth.
. . The finding could be useful in planning future missions to explore Apophis or in protecting Earth from a future impact. "Basic characterization is the first line of defense", said study team member Richard Binzel of MIT. "We've got to know the enemy." Apophis' composition is similar to that of Itokawa, the planetisimal visited by the Japanese Hayabusa mission.
Oct 13, 07: A strange gaseous molecule has been discovered lurking in the atmospheres of both Mars and Venus, scientists announced, adding that it could affect Venus's hyperactive greenhouse effect. The molecule's signature was first noticed in Venus's atmosphere in April 2006, when the European Space Agency's Venus Express arrived.
. . This form of CO2 has one "normal" oxygen attached to its carbon atom, while the other attached oxygen atom has 10 neutrons, instead of the usual eight. The differently-weighted oxygen atoms let the isotope absorb more energy than normal CO2 molecules, which could mean that it contributes more to the greenhouse effect on stifling-hot Venus, the researchers said. (Because the isotope only accounts for about 1% of CO2 molecules on Earth, its contribution to our greenhouse effect is likely very small.)
Oct 12, 07: New images of Pluto and its moons are among the sharpest ever made, astronomers announced. It is so far away that no clear pictures of it exist. The new images are 20 times brighter than those taken of Pluto 30 years ago when its large moon Charon was discovered. Both Pluto satellites are about 5000 times fainter than Pluto. The resulting snapshots are expected to bring astronomers closer to estimating the sizes of Pluto's satellites, Nix, Hydra and Charon.
. . Tholen relied on the adaptive optics system of Keck, which compensates for turbulence from Earth's atmosphere that typically blurs the light from celestial bodies. In addition, Pluto was at its maximum brightness that night.
. . He took 16 images of the system and combined them into a single picture, resulting in clear views of Nix and Hydra, Pluto's small satellites that were discovered in 2005 with the Hubble Space Telescope.
. . The sharp images will show precise positions of the satellites, which will allow astronomers to detect tiny displacements caused by their mutual gravitational tugs. The measurements can be translated into more precise masses for Nix and Hydra. "Once the masses are in hand, we'll be able to say something more definitive about how big these new satellites are." Astronomers have estimated that Nix and Hydra are less than 100 km in diameter, compared with 1,212 km for Charon and about 2,300 km for Pluto.
. . The more definitive measurements are important for scientists planning the 2015 flyby of Pluto with NASA's New Horizons spacecraft. "Something as simple as selecting the proper exposure time to snap images of Nix and Hydra with New Horizons depends on knowing how big they are and how reflective their surfaces are," Tholen said. "One of our goals is to have those answers well in advance of the flyby."
Oct 11, 07: NASA's Dawn spacecraft bound for the solar system's two largest planetisimals has aced the first test of its ion propulsion system, the space agency said. The system will enable Dawn to make the eight-year trek to the planetisimal Vesta and dwarf planet Ceres.
. . Energy efficiency will permit the three ion engines to fire continuously for more than five years, a record for spacecraft, mission managers have said. The ion engines were tested at five different throttle levels and performed "flawlessly". Charged ion particles shoot out of the engines at 144,840 kph to slowly accelerate the spacecraft over time.
. . Dawn is slated to arrive at Vesta in 2011 and spend about a year studying the space rock before meeting the dwarf planet Ceres in 2015. The spacecraft will measure the planetisimals' shape, surface topography, tectonic history, elemental and mineral composition, and look for water-bearing minerals. Scientists will also use Dawn's orbit around Vesta and Ceres to gauge mass and gravity fields.
Oct 11, 07: Ancient gravitational interactions with Venus and Jupiter could help explain some quirks about our moon's orbit, according to a new computer model. Scientists think Earth's only natural satellite was born when a rogue Mars-sized object struck a young and still molten Earth. The collision created a disk of debris around Earth that eventually coalesced to form our moon about 4.5 billion years ago. Today, the moon's rotation is unusual in that its spin axis is tilted, and it travels along a particularly elongated oval-shaped path around the Earth.
. . Matija Cuk, an astronomer at the University of British Columbia in Canada, developed a computer model in an attempt to explain these lunar eccentricities. His model suggests that Venus and Jupiter have elongated our moon's orbit slightly through a phenomenon called gravitational resonance.
. . When the lunar precession and Jupiter's orbital period were equal, about 1 billion years ago according to the new model, Jupiter's small gravitational tug on the moon became amplified with each cycle, Cuk said. According to the model, our moon underwent the same thing with Venus about 2 to 3 billion years ago. If not for those interactions, the moon's orbit would be closer to circular, Cuk said.
Oct 11, 07: On Titan, mornings are eclipsed by dreary drizzles of methane. Getting drenched would be the least of your worries, however, as Saturn's largest satellite plunges to a bone-chilling -183 degrees C at the surface and its swirling orange atmosphere is full of hydrocarbons, such as methane, which is natural gas -—and no oxygen. "Crude oil minus the sulfur is a decent estimate of what the haze is. Really we don't know for sure, but I would describe it as tiny particles of wax that are really, really cold, or waxy snowflakes."
. . Using near-infrared images from Hawaii's W. M. Keck Observatory and Chile's Very Large Telescope, the team of astronomers reveals a nearly global cloud cover at high elevations on Titan. They also found persistent morning drizzle made of methane over the western foothills of Xanadu, Titan's largest "continent."
. . Measuring about 5,150 km across, Titan is larger than Mercury and Pluto and about 40 percent the diameter of Earth. It is the only moon in the Solar System with a dense, planet-like atmosphere (10 times denser than Earth's).
. . Until now, liquid rain was inferred from reports of lakes of liquid hydrocarbon, which scientists presumed were filled by methane precipitation.
. . Adamkovics and his team analyzed infrared measurements throughout Titan's atmosphere. By subtracting out the absorption and scattering due to aerosols low in the atmosphere as well as light from the surface, they were left with a signal that was due to actual droplets of liquid methane. Using a "radiative transfer model", the scientists distinguished between miniscule drops inside clouds and larger ones that form drizzle.
. . The results paint a dreary picture with a global cloud of frozen methane hovering at a height of about 25 to 35 km, liquid methane clouds below 20 km and drizzling methane at lower elevations.
. . The methane droplets inside Titan's clouds are estimated to be a thousand times larger than those in terrestrial clouds. "Because there is a bit less gravity and the atmosphere is thicker on Titan, the rain drops and the cloud drops are really big", he said. Whereas raindrops on Earth are micrometer sized, he said on Titan they appear to be a millimeter or bigger in size. Yet, both contain similar moisture contents, Adamkovics said. And if a cosmic cloud wringer were to empty out Titan's clouds, 1.5 cm of water would blanket the moon's surface.
. . The drizzle or mist appears to dissipate after about 10:30 a.m. local Titan time, which is about three Earth days after sunrise. Titan takes nearly 16 Earth days to rotate once.
Oct 10, 07: Slushy geysers on Saturn's moon Enceladus erupt from fractures clustered around a hot spot at the satellite's south pole, scientists have now confirmed. Using NASA's Cassini spacecraft, researchers recorded the location of jet events on Enceladus for two years. They found that the most prominent jets emanated from hot spots along four cracks, or "tiger stripes", on the moon's surface
. . Cassini's infrared camera detected an anomalous hot spot on the moon's south pole and revealed that pale blue "veins" on the moon's surface were actually deep chasms spewing a mixture of liquid water, ice and organic compounds into space. Scientists now think Enceladus' slushy ejecta are the source of Saturn's tenuous E-ring, and that other Saturnian moons passing through this ring are coated in the reflective substance, making them unusually bright.
. . Recently, scientists have theorized the geysers might be powered by the grinding of ice sheets against one another and the periodic opening and closing of gaps on the moon's surface. Both mechanisms were thought to be driven by a process called tidal heating. Because Enceladus' path around Saturn is elliptical, it is pulled unevenly by the planet's gravity at different points along its orbit. This creates a bulge on the moon's surface that grows and shrinks depending on the moon's distance from Saturn. The repetitive motion generates friction and heat, which scientists suspect drives the tiger stripes to open and close.
. . "Mars has been a candidate for a long time, but even the guys who study Mars will tell you—if they are being at all objective about this—that chances are there are no living organisms on Mars ... unless you go to the poles", she said. Porco thinks Enceladus also has a leg up on Jupiter's satellite Europa, another leading contender in scientists' eyes as a life-harboring world, because many of the suspected requirements for life have already been confirmed on Enceladus.
. . "We've flown through the plumes. We've measured the presence of organics. We already know there's access heat" on Enceladus, Porco said. "The only outstanding question is, do these jets derive directly from liquid water or not?"
Oct 8, 07: Saturn's moon Iapetus has virtually no gray. Rather, its features are all stark black and white. The appearance has long puzzled astronomers. New detailed images suggest sunlight is melting ice on one side of Iapetus, leaving the moon's dark surface exposed, while the opposite half retains its reflective ice-mixed shell. The leading edge of Iapetus, which faces the direction of its orbit, is black as asphalt, while its trailing side appears bright as snow. Iapetus is 1,460 km wide.
. . High-resolution images of Iapetus acquired last month by the Cassini-Huygens spacecraft during its low pass over the moon have uncovered telling details on its surface that may well yield the reason for its strange bright and dark patterns.
. . First, as Iapetus treks around Saturn, its leading edge scoops up a thin coating of dark material, which amplifies sunlight absorption. Over time, as the black-ish surfaces warm, the rate of evaporation increases until finally all the surface ice in that region melts away. Infrared observations from the Cassini flyby confirm the dark dust material is approximately 110 degrees C —warm enough for the release of water vapor from the ice.
. . The water vapor formed then condenses on the nearest cold spot, such as along polar regions and icy areas at lower latitudes on the trailing side of the moon. In that way, the dark material loses the mixed-in ice and gets even darker, while the bright material accumulates more ice and gets brighter, in what the astronomers call a runaway process that leaves no gray area.
Oct 6, 07: A recently discovered space rock that could one day threaten Earth turns out to be an object found seen more than four decades ago but lost in space ever since. The object, thought to be a burned out comet that now resembles an planetisimal, was catalogued as 2007 RR9 this year when found. When it was last seen, in 1960, it carried the designation 6344 P-L. It's considered a "potentially hazardous planetisimal" because part of its orbit is near the path our planet takes around the sun.
. . 2007 RR9 is one of 886 (not 887) known planetisimals bigger than 150 meters that pass within 7.5 million km of Earth. Astronomers did not give an exact diameter for this one. The object poses no specific threat to the planet any time in the foreseeable future. Over time, however, the orbit of a space rock will shift and could cause it to hit the planet. It goes around the sun once every 4.7 years in an elongated orbit that carries it nearly to Jupiter.
Oct 6, 07: A swarm of mirrors flying in formation in space are the best defence against an planetisimal hitting Earth, a study has concluded. Mirrors sent up into space would reflect the sun’s rays to heat up the planetisimal and knock it off course to avoid a devastating impact with the Earth. The technique was found to be the best of several options. Exploding a nuclear device, as seen in the 1998 film Armageddon, was found to be the next best option.
. . A squadron of mirrors was shown to have a high chance of success in pushing planetisimals of any size off course and to be feasible technologically, he told a conference at the U of Manchester’s Jodrell Bank Observatory. The nuclear option was found to be highly successful in dealing with large planetisimals, such as the one believed to have wiped out the dinosaurs 65 million years ago
. . Mirrors in space, or “solar concentrators”, would direct the sun’s rays against a threatening planetisimal to heat the surface sufficiently that it turned to gas. They would be aimed against a small area of the rock, no more than 1.5 meters across, to generate temperatures of at least 2,100C. The evaporating gases would shoot into space, creating the thrust needed to divert the planetisimal and prevent a deadly impact.
. . In 2029, Apophis’s orbit will take it close enough to Earth for the planet’s gravity to possibly alter its trajectory and dramatically increase the chances of an impact on April 13, 2036. The explosion caused by the impact of Apophis, a medium-sixed planetisimal, would be big enough to destroy a city the size of London. A large planetisimal with a diameter of 1,000 meters would have the potential to cause mass extinctions, and the 10km meteor reputed to have ended the reign of the dinosaurs
. . An planetisimal big enough to cause the extinction of the dinosaurs hits Earth on average every 26 million years, said Dr Vasile. It would take 5,000 mirrors operating for three years to deflect it.
. . Nuclear devices would be effective for large planetisimals but could leave dangerous fragments falling towards Earth. Equally the danger of an explosion during take-off was unacceptable.
Oct 1, 07: In 2004, the NASA and European Space Agency spacecraft Ulysses unexpectedly flew through the tail of Comet McNaught. Readings from probe's Solar Wind Ion Composition Spectrometer (SWICS) showed the comet tail slowed down the solar wind, a stream of charged particles which the sun constantly pumps out. Solar wind particles outside the comet tail zipped through space at about 700 km per second, but slowed to 400 km per second inside.
. . They also found the comet tail acted as a source of electrons for the solar wind. The solar wind consists of charged atoms that are missing most of their electrons, but Ulysses found that solar wind particles passing through the comet's atmosphere could regain some of those electrons. The particles exhibit a different charge when they do this, which SWICS can detect.
. . Both findings are a surprise to scientists. The new results contrast with observations made in 1996, when Ulysses passed through the tail of another comet, Hyakutake. That encounter did not reveal the comet tail to have any effect on solar wind speed at all.
Another study announced today showed a solar storm can rip the tail off a comet, and a NASA satellite captured the whole event. The spectacular cosmic crash occurred on April 20 when the sun cast out a coronal mass ejection (CME), or large cloud of magnetized gas. The tempest was thrust directly in the path of Comet Encke, which was traveling around the sun, within the orbit of Mercury. As the gas swept over the comet, its tail brightened and then was separated completely from its parent icy rock and carried away.
. . NASA's pair of Solar Terrestrial Relations Observatory (STEREO) satellites captured the whole incident in newly released images and video.
Sept 27, 07: The Huygens probe landed on Saturn's moon Titan in 2005, but it never encountered chilly seas of liquid methane as mission scientists had hoped --it landed in a mud field.
. . In spite of the disappointment, scientists have recreated a turbulent picture of Titan's atmosphere using data from sensors intended to measure oceanic properties. In addition to showing Huygens probably plunged through turbulent methane ice clouds, the research may aid in the design of balloon probes for future Titan missions.
. . Huygens engineers did not intend to precisely measure the minor, chaotic changes in air known as turbulence, but Lorenz and his team gleaned such data by looking at information from two of the probe's sensors. One of the two, a "liquid density sensor", was designed to measure the properties of Titan's purported methane seas if the probe had floated on one.
. . "Although never designed with atmospheric measurements in mind, this device works as a weakly damped accelerometer." They partnered the density sensor's data with that from a pendulum-like "tilt sensor" to create a play-by-play picture of Huygens' 2.5-hour atmospheric dive.
. . "Future Titan exploration might use lighter-than-air vehicles, which would have to compensate for wind gusts in order to keep above targets of interest for sampling", the study's authors said. Scientists imagine such balloons would be outfitted not only with cameras to detail out Luna's surface, but also spectrometers that could map mineral deposits on Titan. NASA, however, has neither approved nor scheduled such a mission.
Sept 25, 07: The Solar and Heliospheric Observatory (SOHO) has spotted an unusual comet that flies around the sun at regular intervals. Dubbed P/2007 R5 (SOHO), the object belongs to a rare class of comets called periodic comets. Only 190 of the thousands of known comets are periodic. The most famous periodic comet is Halley's Comet, which can be seen from Earth every 76 years and last passed close to the sun in 1986.
. . While many of SOHO's 1,350 detected comets are suspected of being periodic, this is the first one conclusively proven and declared as such. The new comet has a much smaller orbit than Halley, taking only about four years to travel once around the sun.
. . P/2007 R5 (SOHO) is estimated to be about 100 to 200 meters in diameter. Unlike most comets, it does not have a tail or a glowing halo, called a coma, of dust and gas around its head. But as it passed within about 7.9 million km of the sun, the comet brightened by a factor of a million -—a common behavior for a comet.
Sept 21, 07: New images obtained by a sharp-eyed Martian satellite reveal that some Red Planet features once thought to have been carved by flowing water were in fact created by other processes.
. . The bus-sized MRO orbiting spacecraft, launched in 2005, is equipped with six instruments, including the High-Resolution Imaging Science Experiment camera, or HiRISE, which provides 10 times the resolution of any past Mars imagers. While the MRO images are in some cases inconclusive on the question of Martian water, they are painting a picture of the Martian surface for scientists in unprecedented detail.
. . In some cases, the images refute past speculation that some of the features were created by flowing water. They examined images of gully deposits that had been detected last year by the Mars Global Surveyor. The gully deposits were not present in 1999 images but appeared by 2004. The before-and-after images raised hopes that modern flows of liquid water created the deposits. However, observations from MRO suggest a dry origin. Both chemical analyses and images of one of the fresh deposits showed no signs of frost or ice and no evidence for even hydrated minerals, all of which could have given the deposits a "bright" appearance.
. . The researchers also ruled out a hypothesis for an ancient ocean on Mars. The Vastitas Borealis Formation, which covers low-lying northern plains of Mars, was thought to be the result of fine-grained deposits left by an ancient ocean. The new HiRISE images reveal the area, which appeared as flat and featureless in prior missions, is peppered with large boulders.
Sept 20, 07: The next astronauts to work on Luna will likely live in larger habitats and drive sporty new rovers capable of two-week treks, NASA officials said. Rather than assembling a lunar outpost over time from a multitude of small, separately launched modules, NASA is now hoping to land up to three large habitats on fewer flights to build a beachhead on Luna.
. . The first new lunar astronauts could begin to reap science rewards faster than if they had to haul smaller habitat sections and hardware to Luna on each flight, then combine them into a larger base to support long-duration expeditions.
. . NASA has eyed Luna's Shackleton Crater near the lunar south pole as a possible moon base site because of its proximity to permanently lit and shadowed regions that could be key for solar power stations and the hunt for water ice. But Cooke said that Shackleton is not the only candidate for a moon base, especially since the revised plan calls for mobile habitat modules that could move between science targets or gather together in a sort of lunar spare parts depot.
. . Both rovers would be deployed together, each with a crew of two astronauts. If one rover failed, all four spaceflyers could pile into the remaining vehicle to return to their lunar base, Gernhardt said. Current plans call for a 2,250-kg pressurized vehicle with seats that fold into beds for longer trips.
. . The two-person rovers would be equipped to handle three-day, seven-day and two-week excursions on Luna with exterior-mounted spacesuits that could be donned by climbing through a shared hatchway, Gernhardt said. It could take just 10 minutes to step into the spacesuits and onto the lunar surface. Short jaunts could cover about 40 km with the two-week trips roving across 960 km.
Sept 18, 07: New measurements reveal Neptune's south pole is warmer than the rest of the planet, as expected. But it's still frigid. The polar region's relative warmth could provide a route for methane gas to escape from the deep atmosphere, explaining mysterious hot spots that have been reported there.
. . Neptune's Southern Hemisphere, because of the planet's tilt and orbit, has been bathed for about 40 years in the sparse sunrays that can reach there. Temps at the south pole are elevated by about 10 degrees Celsius compared with the rest of the planet, for which the average temperature is an icy -200 degrees C. "The temperatures are so high that methane gas, which should be frozen out in the upper part of Neptune's atmosphere (the stratosphere), can leak out through this region."
Sept 13, 07: Wobbles in the rotation of Mars swung the planet into about 40 extreme ice ages in the past 5 million years and allowed thick ice layers to remain far away from the poles, an astronomer says.
. . Various spacecraft have revealed evidence for ice ages on Mars. Around 4 million to 5 million years ago, precipitation events sent piles of snow and ice that accumulated around the ice caps. Nowadays, the only visible ice on Mars is the pair of polar caps. But in recent years, orbiting probes have found solid evidence for vast sheets of underground ice near the red planet's equator, at what scientists call mid-latitudes.
. . How ice ended up so far from the poles has remained a mystery. The answer could be in the wobble of Mars.
. . Mostly due to Mars' lack of a stabilizing moon, its tilt can wobble as much as 10 degrees from the current 25-degree angle. Using computer simulations, Schorghofer found that while not topsy-turvy, the wobbles change the amount of sunlight reaching Mars' surface and can cause vast amounts of ice to shift between the poles and the rest of the planet every 120,000 years. The wobble would leave two types of ice on or near the surface of Mars: the very old massive ice sheet and the recent pore-ice, less than half a million years old. Dry soil covers both types of ice.
. . "Today, this gives rise to pore-ice at mid-latitudes and a three-layered depth distribution in the high latitudes." At high latitudes, the original ice sheet is covered by a layer of pore-ice, which is veiled by a layer of dry sediment.
. . When the Phoenix Lander spacecraft arrives at Mars, which is expected in 2008 and will land in the Martian north polar region, Schorghofer expects it will "see" the abundant and layered ice forms.
Sept 11, 07: Tiny meteors, typically no larger than a grain of sand, frequently bore hot tunnels through Earth's air to leave behind thin, glowing trails of gas. The trails were estimated to be narrower than a meter, but until now, more precise measurements have been impossible to make.
. . Turns out they are amazingly thin compared to the light show they create. Meteor trails begin about 120 km above Earth's surface, a region that is not typically focused on by ground-based telescopes or satellites.
. . Astronomers measured the streaks to discover that they can be as thin as a few millimeters across. The measurements mark the first time a meteor track's width has been precisely measured solely using light emitted from the event.
Sept 5, 07: A collision 160 million years ago of two planetisimals orbiting between Mars and Jupiter sent many big rock chunks hurtling toward Earth, including the one that zapped the dinosaurs, scientists said.
. . Their research offered an explanation for the cause of one of the most momentous events in the history of life on Earth --10-km-wide meteorite striking Mexico's Yucatan peninsula 65 million years ago. That catastrophe eliminated the dinosaurs.
. . U.S. and Czech researchers used computer simulations to calculate that there was a 90% probability that the collision of two planetisimals --one about 150 km wide and one about 60 km wide --was the event that precipitated the Earthly disaster.
. . The collision occurred in the planetisimal belt. The planetisimal Baptistina and rubble associated with it are thought to be leftovers, the scientists said. Some of the debris from the collision escaped the planetisimal belt, tumbled toward the inner solar system and whacked Earth and our moon, along with probably Mars and Venus.
. . While the bombardment of this region of the solar system due to this shower of debris peaked about 100 million years ago, the scientists said the tail end of the shower continues to this day. Bottke said many existing near-Earth planetisimals can be traced back to this collision.
. . It blasted out the Chicxulub (pronounced CHIK-shu-loob) crater measuring about 150 km wide. The researchers looked at evidence on the composition of this meteorite and found it consistent with the stony Baptistina. The researchers estimated that there also was about a 70% probability that the prominent Tycho crater on Luna, formed 108 million years ago and measuring about 85km across, also was carved out by a remnant of the earlier planetisimal collision.
. . The sleuths were guided by an intriguing clue --a large planetisimal called (298) Baptistina, which shares the same orbital track as a group of smaller rocks. Turning the clock back, the simulation found that the Baptistina bits not only fitted together, they were also remnants of a giant parent planetisimal, around 170 km across, that once cruised the innermost region of the planetisimal belt.
. . Around 160 million years ago --the best bet in a range of 140-190 million years-- this behemoth was whacked by another giant some 60 kms across. From this soundless collision was born a huge cluster of rocks, including 300 bodies larger than 10 kms and 140,000 bodies larger than one km. Over aeons, the fragments found new orbits with the help of something called the Yarkovsky effect, in which thermal photons from the Sun give a tiny yet inexorable push to orbiting rocks.
. . As the family gradually split up, a large number of chunks --perhaps one in five of the bigger ones-- crept their way out of the planetisimal belt and became ensnared by the gravitional pull of the inner planets.
. . They took their theory a stage further and checked out sediment samples from the Chicxulub site. Putting simulation and chemical evidence together, the team rule out theories that a comet was to blame rather than an planetisimal, and say there is a "more than 90%" probability that the killer rock was a refugee from the Baptistina family.
. . The investigators also put a 70% probability that a four-km Baptistina planetisimal hit Luna some around 108 million years ago, forming the 85-km crater Tycho. The probability is lower than for Chicxulub because it is based only on a simulation. Bottke: "Our simulations suggest that about 20% of the present-day near-Earth planetisimal population can be traced back to the Baptistina family."
Sept 1, 07: UK space scientists and engineers have designed a mission to investigate a potentially hazardous planetisimal. The 300m-wide rock, known as Apophis, will fly past Earth in April 2029 at a distance that is closer than many communications satellites.
. . Astrium, based in Stevenage, Herts, wants a probe to track the planetisimal so its orbit can be better understood. The concept will compete for a $50,000 (£25,000) Planetary Society prize, but a full mission would cost millions.
. . The British design calls for a small, remote-sensing spacecraft, dubbed Apex (Apophis Explorer), which could rendezvous with Apophis in January 2014. It would then spend the next three years tracking the rock, sending data back to Earth about the object's size, shape, spin, composition and temperature. From this information, orbit modelling would enable a more accurate measure of orbit.
. . Apophis caused some consternation in 2004 when initial observations suggested there was an outside chance it might hit Earth in 2029.
Aug 30, 07: Mysterious waves that help transport the sun's energy out into space have been detected by scientists for the first time. Researchers hope their discovery of the energetic ripples, known as Alfven waves, will shed light on other solar phenomena such as the sun's magnetic fields and its super-hot corona, or outermost atmosphere.
. . Like a wave traveling along a string, Alfven waves run along the sun's magnetic field lines and reach deep into space. While astrophysicists have identified the waves far away from the sun, they've never been detected close to our star-the ripples were too small and too fast to spot.
. . To observe the elusive waves, Tomczyk and his colleagues pointed the coronal multichannel polarimeter (CoMP) instrument. Thanks to CoMP's imaging speed of one picture every 15 seconds, the scientists captured the waves traveling at about 14.5 million kph. "The waves are visible all the time and they occur all over the corona, which was initially surprising to us", said Scott McIntosh.
Aug 29, 07: It is a commonly held belief that Jupiter shields Earth from comets or asteroids that might otherwise hit us. This idea is based on a 1994 study that looked at comets originating from outside the Solar System.
. . New research, presented at the European Planetary Science Congress, has looked at the effect of Jupiter on comets already within our Solar System. It seems that, whilst Jupiter does deflect some comets away from us, it sends almost as many comets towards us.
. . Five scenarios were run, the first with our Solar System, then replacing Jupiter with a planet that was three-quarters, a half and a quarter of the mass of the gas giant; and finally with no Jupiter at all. The results showed that the numbers of Earth impact events were the same for the cases with the real Jupiter and with no planet at all.
Aug 28, 07: Ancient bacteria are able to survive nearly half a million years in harsh, frozen conditions, researchers said in a study that adds to arguments that permafrost environments on Mars could harbor life. They tested the microbes living up to 10 meters deep in permafrost collected from Northern Canada, the Yukon, Siberia and Antarctica.
. . The findings also represent the oldest independently authenticated DNA to date obtained from living cells and could offer clues to better understand ageing, said Eske Willerslev, a researcher at the U of Copenhagen who led the study. "When it can live half a million years on Earth it makes it very promising it could survive on Mars for a very long time", Willerslev said. "Permafrost would be an excellent place to look for life on Mars."
. . When a cell dies, its DNA fragments into pieces but the samples the researchers studied were all very long strands --evidence the cells were able to continuously repair genetic material and remain alive, said Willerslev. This is interesting because the temperature on Mars is much colder with more stable temperatures, representing an even better environment to sustain this kind of life, he added.
. . While most scientists think our neighbor in the Solar System is lifeless, the discovery of microbes on Earth that can exist in environments previously thought too hostile has fuelled debate over extraterrestrial life.
Aug 22, 07: Uranus: The rings are currently edge-on to Earth, in an event that only happens every 42 years.
. . A team has analysed the rings' structure, with some surprising results.Their images show that the rings are changing much more quickly than researchers had previously believed. The edge-on perspective is considered favourable for seeing particular features in the rings. It makes the outer rings that contain centimeter- to meter-sized rocks seem dimmer as they obscure each other; but those that are normally almost transparent layers of dust become more visible as the material merges into a thin band along the line of sight.
. . Astronomers can also look for other properties not measurable from other angles, like warps or waves in the ring structure, the thickness of different rings and their inclination and orientation.
. . "Two little satellites called Cordelia and Ophelia straddle the brightest ring, the epsilon ring, and keep it in place, but people have always assumed there must be a bunch more of these satellites that are confining the nine other narrow rings", said Mark Showalter from the Seti Institute in California.
. . The group is waiting for the Uranus equinox, which occurs in December. At this time, the planet's rings are edge-on to the Sun, and the position of the Earth will allow astronomers to see the rings at a steep angle with no glare from our star.
Aug 23, 07: Mars was wet in its early history, but today it appears bone dry other than ice below the surface and at the poles. Astronomers have long wondered where all the water went. The water might have been blown into space long ago by strong gusts of solar winds, new satellite observations suggest.
. . The findings, presented this week at the European Planetary Sciences Congress in Potsdam, Germany, also show that solar flares erupting on the far side of the sun can still affect the "space weather" of Earth.
. . Other scientists have speculated that the missing water escaped from the Martian atmosphere, blown into space by the solar wind. Unlike Earth, Mars does not have a protective magnetosphere, so the solar wind and high-energy particles directly interact with its atmosphere. Past studies have observed large quantities of charged oxygen atoms-a primary component of water-in Mars' atmosphere streaming into space. However, the observed outflows were not high enough to account for all of the planet's missing water.
. . Data collected at the red planet during the 2006 eruptions by Mars Express showed higher than average amounts of oxygen ions leaking away into space. If this occurred regularly over billions of years, it could account for Mars' missing water, speculated study team member Yoshifumi Futaana.
. . The observations also suggest that solar flares on the far side of the sun can still impact the space weather of planets not in their direct line of sight-something that scientists had only speculated about before.
Aug 23, 07: Tiny grains of ice or particles of space dust could significantly damage the Cassini spacecraft when it passes close by Saturn's moon Enceladus next March, scientists said. Images from Cassini beamed back to earth in 2005 showed multiple jets emanating from the moon's south polar region that scientists suspect arise from warm fractures, known as tiger stripes.
. . The upcoming flyby in March 2008 will offer a unique view of the little-understood plumes shooting out from these fissures but has also raised concern that this could stir up particles that damage the spacecraft.
. . Cassini will pass by Enceladus at an altitude of less than 100 km, perhaps moving through some of the spray, which some scientists believe may be made up of water spurting out from the moon under pressure. "These plumes were only discovered two years ago and we are just beginning to understand the mechanisms that cause them."
. . "A grain of ice or dust less than two millimeters across could cause significant damage to the Cassini spacecraft if it impacted with a sensitive area." There's about a one in five hundred chance of being hit by a dangerously large particle.
Aug 23, 07: The soil on Mars may contain microbial life, according to a new interpretation of data first collected more than 30 years ago. The search for life on Mars appeared to hit a dead end in 1976 when Viking landers touched down on the red planet and failed to detect biological activity.
. . But Joop Houtkooper of the U of Giessen, Germany, said on Friday the spacecraft may in fact have found signs of a weird life form based on hydrogen peroxide on the subfreezing, arid Martian surface.
. . His analysis of one of the experiments carried out by the Viking spacecraft suggests that 0.1% of the Martian soil could be of biological origin. That is roughly comparable to biomass levels found in some Antarctic permafrost, home to a range of hardy bacteria and lichen.
. . Houtkooper believes Mars could be home to just such "extremophiles" -- in this case, microbes whose cells are filled with a mixture of hydrogen peroxide and water, providing them with natural anti-freeze. They would be quite capable of surviving a harsh Martian climate where temperatures rarely rise above freezing and can fall to minus 150 degrees C.
. . One scientist called it "bogus".
July 26, 07: Proposals for a multibillion dollar Mars sample return mission --perhaps even a comprehensive sample return program-- appear to be on the front burner again, but not without controversy.
. . Alan Stern, NASA's new associate administrator for the Science Mission Directorate, is a big proponent of Mars sample return. But while many NASA planetary scientists share that sentiment, a number of others also worry that such an ambitious mission - Stern estimates it could cost from $3 billion to $4 billion - would suck up all the available money for most other Mars missions in the next decade and disrupt NASA's ability to send at least one robotic mission to Mars every two years.
July 23, 07: There's a strange moon whizzing around Saturn that's shaped, oddly, like a walnut. Astronomers find that Iapetus got its shape from a super-fast spin that was frozen into place early in the solar system's formation.
. . Astronomers think this characteristic shape persists because Iapetus was cryogenically frozen in time about 3 billion years ago. Running exactly along its midsection, a chain of mountains 1,300 km long and 19 km high adds to the moon's walnut-like appearance.
. . Its rotation has slowed to its present, nearly 80-day period. Iapetus originally spun once every five to 16 hours, which was fast enough to buckle its surface at the equator. In order to slow the young moon down its present once-per-80-days rotational speed, Castillo explained, "its interior had to be much warmer, close to the melting point for water ice."
July 20, 07: A new moon of Saturn has been discovered, bringing the total up to 60. Jupiter has 63.
. . Initial measurements suggest the new moon, which is still unnamed, is about 1.2 miles (2 kilometers) wide, and lies between the orbits of Mehone and Pallene, two Saturnian moons discovered by NASA's Cassini spacecraft in 2004. The newfound moon is about 1.09 million miles (1.76 million kilometers) from Saturn and could be part of a larger group of still undiscovered moons around the ringed planet.
. . There is an ongoing debate about what size a satellite must be and how it must behave to qualify as a moon. If very small and as-yet unfound objects are ultimately included, the moon tallies could soar into the hundreds or even thousands.
July 17, 07: Slushy geysers on Pluto's moon Charon apparently coat the tiny world in ice crystals, making it something like the outer solar system's equivalent of an ice machine. A very, very slow ice machine. Water is likely trickling out at a glacial pace, researchers say, repaving Charon in a thin layer of 1-millimeter deep ice every 100,000 years.
. . The finding hints at water ice inside Charon and has implications for other Kuiper Belt Objects. There are no photos of the geysers or the ice. Instead, astronomers learned of the ice deposits after discovering the spectral fingerprints of ammonia hydrates and water crystals in light coming from the moon. The findings suggest that ammonia-laced liquid water from deep inside Charon is seeping out through cracks onto the moon's frigid surface. The researchers ruled out other possible mechanisms for the ice and concluded it must be due to cryovolcanism --the eruption of liquids and from inside the moon. "That implies that Charon's interior possesses liquid water."
. . Cryovolcanism also occurs on other moons in the solar system, including Saturn's moon Enceladus and the Jovian satellite Europa. However, both these moons are tidally squeezed by the strong gravitational tug of their giant planets, which forces water out through cracks.
. . The reserachers suspect something different is happening with Charon, which isn't tidally tugged by Pluto. Heat from radioactive materials in Charon's interior might be creating a pool of melted water beneath the moon's surface. The ammonia functions like an antifreeze and prevents the liquid water from turning solid.
July 13, 07: Mars, as it turns out, once had a propensity for juggling its polar ice caps from one end of the planet to the other.
. . A perennial wobble in Mars' tilt tipped one pole closer to the sun, causing water ice to evaporate and refreeze at the colder pole, new research shows. [I know; this makes no sense! Six months later, the *other* pole is tipped that way.] Every 51,000 Martian years, the wobble would bring the colder pole closer to the sun again and shuffle the ice cap back to the opposite pole. "But something stopped the cycle, and we don't know what it was."
. . As the sun evaporated water ice from the warmer pole, the vapors eventually made their way to the opposite pole. Once the water reached the chilly terrain pointed away from the sun, it refroze.
. . So far, the research team's best explanation for the multi-millennia-long cycle's end is that a thick slab of dry ice, or frozen CO2, capped the water ice in Mars' southern pole.
July 9, 07: NASA is set to launch a robotic spacecraft next month that will dig into the soil near the northern pole of Mars to check for conditions favorable to microbial life now or in the planet's past.
. . The Phoenix Mars Lander is due to launch some time between August 3 and August 24 from Florida for a landing on the frigid northern plains of Mars on May 25, 2008, NASA officials and mission scientists said. The mission is due to last three months. NASA is eyeing a landing site devoid of boulders at a latitude equivalent to northern Alaska on Earth.
. . The lander will wield a robotic arm 7.7 feet long to dig up to 3 feet (1 meter) deep to get at soil and frozen water thought to be lurking just under the surface. It will rely on a variety of equipment to assess whether this water may provide conditions that could support microbes.
. . With its solar panels unfurled, measures about 5.5 meters wide and 1.5 meters long. The equipment can detect organic materials. "We can't tell whether it's DNA or proteins, but we can tell they're complex organics."
. . It will use a heat shield to slow its entry from space, and then a parachute will further slow its descent to about 135 mph (217 kph). The lander will then free itself from the parachute and fire rocket engines to slow to about 5.5 mph (8.8 kph) before landing on three legs, NASA said.
July 4, 07: One of the strangest moons in our solar system is Hyperion, a Saturnian satellite so pockmarked by deep craters that it looks like a giant, rotating bath sponge adrift in space. New image analyses suggest the moon's odd appearance is the result of a highly porous surface that preserves craters, allowing them to remain nearly as pristine as the day they were created. The finding is just one of several new details about the quirky moon revealed in two studies.
. . Scientists determined that Hyperion is composed mostly of water ice and that the bottoms of its craters are covered in a dark red gunk that could be the key to resolving some of the moon's other strange properties.
. . It is one of the largest non-spherical bodies in the solar system. The moon is oval shaped and about 400 km at its widest point. Unlike most of Saturn's other satellites, it is not tidally locked. Instead, Hyperion undergoes "chaotic rotation", meaning its axis of rotation shifts so much that scientists can't reliably predict its orientation in space.
. . Hundreds of craters cover the surface, with most averaging 2 to 10 km wide. The latest analyses of data obtained by NASA's Cassini spacecraft during its flybys of Hyperion in 2005 and 2006 show that about 40% of the moon is empty space.
. . Hyperion's high porosity could explain its sponge-like appearance, scientists say. A large meteor striking Earth's moon will gouge a deep hole on the surface and send up a giant spray of rock and dust. The excavated material rains back down onto the lunar surface and into other craters, partially filling them in. In contrast, the surface of Hyperion is so brittle that an object striking it will create a hole but not send any material flying. Surrounding craters remain as deep as when they first formed. The new analyses also confirmed that Hyperion is composed mostly of water ice with very little rock.
. . Cruickshank's team attributes the moon's dinginess to contamination by a dark, organic material that litters Hyperion's surface and is concentrated in several of its craters. The reddish gunk contains long chains of carbon and hydrogen and appears very similar to material found on other Saturnian satellites, most notably Iaeptus.
. . The third-largest moon of Saturn, Iaeptus is an unusual two-toned world with one half covered in gleaming ice and the other half coated in the same mysterious dark material that covers Hyperion.
. . This link has some scientists speculating that Hyperion's strange shape and Iaeptus' odd paint job share a common origin. According to this idea, a giant object collided with a still-round Hyperion in the distant past. The impact sent Hyperion into a cosmic spin that it is still reeling from today and caused a shower of dust-like particles to fly outwards through space, where it struck Iapetus.
. . The same reddish gunk can also be found on other icy objects in the outer solar system, including other moons, Kuiper belt objects and comets.
July 3, 07: NASA said it is recycling two used spacecraft. Both successfully completed their primary missions to two different comets and their discoveries have helped scientists understand how the solar system formed.
. . Deep Impact will pass the comet 85P/Boethin in December 2008. It will be the first spacecraft to explore Boethin, a small comet discovered in 1975 that orbits the sun every 11 years. Researchers hope information gathered from Boethin will shed light on how comets evolved and if they played a role in the emergence of life on Earth.
. . NASA plans to send Stardust to Tempel 1 to examine the crater created by the 2005 impact, making it the first comet to be revisited. Scientists failed to image the crater after the collision because the plume blocked the view, but they hope to get a second chance with Stardust when it flies by the comet in 2011.
July 1, 07: Europe is keen to see a crew transport system that is independent of the US Orion vehicle, which is set to replace the space shuttles in the next decade. The new Crew Space Transportation System (CSTS) could be an updated and enhanced version of the venerable Russian Soyuz approach or an entirely new concept. "We need two transportation systems; we cannot rely on only one", said Daniel Sacotte, Esa's director of Human Spaceflight.
. . Europe's Automated Transfer Vehicle (ATV) is about to be despatched to a spaceport for launch to the International Space Station (ISS). The ATV --essentially a 20-ton cargo ship-- incorporates advanced automated rendezvous and docking systems that could be employed in some future CSTS.
Jun 28, 07: The differences between dusty Mars and lush, vibrant Earth are more than just skin deep. The two planets are different down to their very core.
. . Earth contains a heavy version of silicon that is absent from Mars. The finding suggests Earth's core formed under very different conditions from those on Mars. It also supports the idea that Luna formed from material torn from early Earth by a collision with a planet-sized rock.
. . Rock samples from Mars and the giant planetisimal Vesta show they contain a lighter form, or "isotope", of silicate that is identical to those found in a primitive class of meteorites called chondrites. Scientists think chondrites are shed remnants of the original building blocks of planets that have fallen to Earth. Silicates are compounds made of silicon and oxygen mixed with other elements.
. . "The most likely explanation is that, unlike Mars or Vesta, the Earth's silicon has been divided into two sorts-a portion that became a light element in the Earth's core dissolved in metal and the greater proportion which formed the silicon-oxygen bonded silicate of the Earth's mantle and crust."
. . Earth is eight times more massive than Mars, and this could partly explain the differences in the planets' core compositions, the scientists say. It might be that silicates in our planet's core transformed into denser forms under the greater pressure conditions on Earth.
. . The research also showed that Luna contains the same silicon ratio as Earth. Luna is much smaller than either Earth or Mars, and is therefore not massive enough for its core to experience the kinds of pressures needed to change silicon from one form to another.
. . The finding is, however, consistent with the theory that our Moon was born when a Mars-sized planet, usually called "Theia", collided with early Earth. The impact carved out a large molten chunk from Earth which eventually coalesced into Luna.
. . The identical nature of the silicon composition on Luna and Earth suggests our planet must have already undergone the core transformations necessary to make the heavier isotope before Luna formed about 40 million years after the start of the Solar System.
Jun 27, 07: In late June of 1908, a fireball exploded above the remote Russian forests of Tunguska, Siberia, flattening more than 800 square miles of trees. Researchers think a meteor was responsible for the devastation, but neither its fragments nor any impact craters have been discovered. Astronomers have been left to guess whether the object was an planetisimal or a comet, and figuring out what it was would allow better modeling of potential future calamities.
. . Italian researchers now think they've found a smoking gun: The 50-meter-deep Lake Cheko, located just 8km northwest of the epicenter of destruction. "When we looked at the bottom of the lake, we measured seismic waves reflecting off of something. Nobody has found this before. We can only explain that and the shape of the lake as a low-velocity impact crater."
. . Should the team turn up conclusive evidence of an planetisimal or comet on a later expedition, when they obtain a deeper core sample beneath the lake, remaining mysteries surrounding the Tunguska event may be solved.
. . "To really find out if this is an impact crater", Long said, "we need a core sample 10 meters into the bottom" in order to investigate a spot where the team detected a "reflecting" anomaly with their seismic instruments. They think this could be where the ground was compacted by an impact or where part of the meteorite itself lays: The object, if found, could be more than 10m in diameter and weigh almost 1,700 tons.
. . "In 1947, the Russian Sikhote-Alin meteorite created 100 small craters. Some were 20 meters (66 feet) across", Harris said. A site in Poland also exists, he explained, where a large meteor exploded and created a series of small lakes. "If the fragment was traveling slowly enough, there's actually a good chance (Longo's team) will unearth some meteorite material", Harris said.
Jun 22, 07: Mars will be transformed into a shirt-sleeve, habitable world for humanity before century's end, made livable by thawing out the coldish climes of the red planet and altering its now CO2-rich atmosphere.
. . Lowell Wood, a noted physicist and recent retiree of the Lawrence Livermore National Laboratory presented his eye-opening Mars manifesto, laying out a scientific plan to "experiment on a planet we're not living on." It could be underway by the middle of this century and essentially complete by the end of the 21st century.
. . Terraforming nay-sayers seem to ignore the fundamentals of population genetics, sociobiology and human history, he argued. Mars is far easier to terraform than Luna: "It's kids' stuff as far as rendering it [Mars] into something that's human habitable quickly and easily. Luna is a good bit tougher."
. . Wood said that Mars currently is "stuck" in a semi-permanent "thermal depression." But there is a multiplicity of design solutions, he foresees, such as engineering an artificial greenhouse effect at the planet that warms the world and makes it "a more preferred planet."
. . Overall, Wood said that a workable plan can be scripted to raise the average temperature of Mars, rid the world of excess CO2, as well as generate soil to support agriculture. After roughly one to three decades of such warming, Wood continued, the "Great Spring" literally erupts all over Mars. It's all a matter of trimming-and-tailoring a thawed Mars to the "biospheric optimum", he concluded. It is not technology, nor money, he said, the pacing ingredient is marshaled will.
Jun 22, 07: Scientists have taken a giant leap toward making possible the dream of building a powerful telescope on the moon that could withstand even the harshest of lunar conditions. They said they coated a special type of liquid surface with a layer of silver to make a highly reflective mirror like one that could be used in any future, moon-based telescope.
. . Borra envisions a telescope with a liquid mirror measuring 20 to 100 meters wide. Such a telescope, which has drawn NASA's interest, could provide astronomers on Earth unprecedented views into distant reaches of the universe, studying objects far more faint even than NASA's planned James Webb Space Telescope, due for a 2013 launch.
. . Astronomers hope such an instrument could allow them to study the early phases of the universe after the Big Bang. Advocates say a large telescope on the moon would be more cheaply and easily built using a liquid mirror rather than a conventional glass one. The researchers think any liquid-mirror telescope on the moon would not come before 2020 at the earliest.
. . The scientists made use of a liquid made of "ionic salts" that remains fluid at super-low temperatures. They deposited a thin layer of chromium particles on the liquid, then added a layer of silver particles to complete the mirror. The silver layer that is created is completely smooth, highly reflective, can stay stable for months, and the ionic liquid that it covers does not evaporate.
Jun 20, 07: The Phoenix Mars Lander is set to scope out Mars' frozen pole for life-supporting conditions next May, but researchers are predicting a tricky soil-sampling mission. If the spacecraft's rockets don't blast the topsoil away, the exhaust fumes could contaminate it with fuel. Or, Martian surface winds might simply blow away the samples before they can be dumped into the lander.
Jun 20, 07: The Hubble Space Telescope has imaged two of the largest known planetisimals, revealing craters and other features that will soon be the targets of close-up observations by NASA's Dawn spacecraft.
. . Ceres is round, like a planet, and 950 km wide. The rock, about the size of Texas, contains some 30 to 40% of all the mass in the planetisimal belt between Mars and Jupiter. Ceres is now considered a dwarf planet. Vesta, the other target, is irregularly shaped and about 530 km wide.
. . On July 7, NASA plans to launch Dawn-a mission that had been cancelled but was reinstated last year-on a four-year journey to the planetisimal belt. The robotic probe will go into orbit around Vesta in 2011 and Ceres in 2015. The new images will help astronomers fine tune mission plans.
. . The picture of Vesta allowed astronomers to map the planetisimal's southern hemisphere. A crater there, caused by an ancient collision, is a whopping 456 km across. Researchers have known that the collision spawned many smaller planetisimals that they call vestoids.
. . Color differences in the image reflect differences in surface chemicals, some of it possibly due to volcanic activity, that Dawn will explore for clues to the planetisimal's interior structure. The effects might be similar to dark "seas" and bright highlands on Earth's moon.
. . Ceres' round shape suggests its interior is layered, like Earth's is, astronomers said. It might have a rocky core, an icy mantle and a thin dusty crust. There could be water inside, too.
Jun 18, 07: China plans to develop a new generation of carrier rockets with a payload capacity large enough to launch a space station, state media reported. China attaches great prestige to its space program, seeing it as a way to validate its claims to being one of the world's leading scientific nations. The payload capacity of China's Long March series of carrier rockets will be more than doubled from 9.5 tons to 25 tons in order to advance the country's lunar exploration program. The official did not say when the rockets would be ready for launch.
Jun 14, 07: Pluto has been demoted again. Calculations published on Thursday show the distant world that astronomers no longer deem a planet is not even the largest of the Solar System's so-called dwarf planets --it is smaller than recently discovered dwarf planet Eris. It's 27% more massive than Pluto, they found, & has a small moon. Eris is about half the size of Luna. It has a diameter of 1,500 miles, just bigger than Pluto's 1,400 miles.
. . Scientists previously had figured that Eris's diameter was bigger than Pluto's but did not know about mass. "It is covered in an almost perfectly uniform white frost. So it looks just like a white billiard ball out there", Brown said. Eris's orbit is highly elongated and takes 560 years. It ventures anywhere from 3.5 billion miles to 10 billion miles from Sol.
. . Pluto, whose 250-year orbit on occasion brings it inside the orbit of the outermost planet Neptune, journeys as far as 5 billion miles from Earth, Brown said. Brown said there are roughly 50 known objects in the solar system that can be classified as dwarf planets.
. . It also confirms Eris and Pluto have similar compositions. The researchers used the Hubble Space Telescope and the Keck Observatory to calculate the orbital speed of its moon, Dysnomia. According to Newtonian physics, the more massive a celestial object is, the faster its satellite will zip around it. "So by looking at the time it takes the moon to go around Eris, we're able to calculate the mass", Schaller said.
. . Dysnomia is thought to be less than 150 km across and to take about 16 Earth-days to make one trip around Eris.
. . Eris itself is believed to have a diameter of 2,400 to 3,000 km. Pluto has a diameter of about 2,300 km. Eris' density is similar to that of Pluto, and that it is therefore likely made up mainly of rock and water ice.
. . Ceres was first discovered in 1801, it was classified as a planet on account of its large size: 850km.
Jun 12, 07: Long, undulating features on the northern plains of Mars probably are remnants of shorelines of an ocean that covered a third of the planet's surface at least 2 billion years ago, scientists said. The Global Surveyor found big, mountain-sized variations in elevation along the suspected shorelines, whereas a shoreline should be a constant elevation matching sea level.
. . But scientists said the movement of the Martian poles and also the planet's spin axis by roughly 2,000 miles in the past 2 billion to 3 billion years would have triggered deformation of surface features just like that seen in the suspected coastlines.
. . At some point, a big shift of mass on Mars caused its north pole to shift 50 degrees toward its present location and the planet's change in orientation changed the topography of the shorelines.
. . The ocean may have covered a third of the Martian surface during the first half of the planet's history before disappearing at least 2 billion years ago. The elevation of the Arabia shoreline changes by 2.5 km, while the Deuteronilus shoreline varies by four-tenths of a mile.
. . The researchers said another important Martian geological feature --the volcano Tharsis, the biggest in the solar system-- lends support to their hypothesis on polar movement. Tharsis is so massive it would always keep itself on the spinning planet's equator, they said. They calculated that the suspected path taken by the moving poles would have preserved the volcano's equatorial position.
Jun 12, 07: The enigmatic Saturnian moon Titan is still yielding surprising new details years after scientists first pierced its thick haze veil. The vision now emerging of Saturn's largest moon, with its giant dunes and oceanless surface, is perhaps a glimpse of Earth's desert future.
. . The surface of Titan was a total mystery before the Huygens probe infiltrated past its dense hazy atmosphere in 2005. After a seven-year voyage aboard the Cassini spacecraft, Huygens spent roughly two-and-a-half hours parachuting down and then sent transmissions from Titan's surface for another 70 minutes before Cassini moved out of range. "Even though we have only four hours of data, it is so rich that after two years of work we have yet to retrieve all the information it contains."
. . Stereoscopic images from Huygens now reveal extremely rugged terrain in the bright highlands north of the probe's landing site. This includes channels divided by ridges that can rise some 500 to 650 feet high, with slopes of 30 degrees. Their shapes suggest they are drainage channels, cut by liquid methane falling as rain.
. . "Rains on deserts on Earth can take be spaced by months to years, but on Titan we're talking about hundreds, maybe thousands, of years between episodes of major rainfall that comes down perhaps violently", Lunine said. "Because Titan is so much farther from the sun than Earth is, it takes longer for solar energy to evaporate methane and build it up in the atmosphere enough to generate storms."
. . Before Huygens penetrated Titan's haze, scientists suspected oceans of liquid methane and ethane covered its surface, evaporation from which could explain the smog-like compounds in its atmosphere. Instead, they found giant dunes likely composed of sugar-sized hydrocarbon grains girdling its equator, each stretching up to 95 km long across dark plains that bear markings suggesting occasional flash flooding.
. . Any surface lakes and seas might be confined to Titan's polar regions. "There's a sense here of a desert world. Not in terms of being hot-Titan is very cold-but in terms of being very dry."
Jun 6, 07: A very dark spot on Mars could be an entrance to a deep hole or cavern, according to scientists studying imagery taken by NASA's Mars Reconnaissance Orbiter.
. . The geological oddity measures some 100 meters across and is located on an otherwise bright dusty lava plain to the northeast of Arsia Mons, one of the four giant Tharsis volcanoes on the red planet. The hole might be the sort of place that could support life or serve as a habitat for future astronauts --nifty underground housing to protect against the high-radiation environment of Mars. Additionally, caves offer easier subsurface access for direct exploration and drilling, she suggests, and may provide extractable minerals, gases, and ices.
. . Because the spot lacks a raised rim or tossed out material called ejecta, researchers have ruled out the pit being an impact crater. No walls or other details can be seen inside the hole, and so any possible walls might be perfectly vertical and extremely dark or --more likely-- overhanging. HiRISE image specialists said the pit must be very deep to prevent detection of the floor from natural daylight, which is quite bright on Mars.
. . In April, it was announced that the NASA Mars Odyssey and its Thermal Emission Imaging System (THEMIS) found near the equator seven dark spots that scientists think could be entrances to underground caves.
. . The deeper and deeper you go down on Mars, the warmer and warmer it gets, Smith said, and at some point the conditions are just right where liquid water is stable. Moreover, could caves be linked to underground fractures allowing water vapor to be trapped inside, Smith speculates, perhaps the sort of comfy environment ideal for biology.
. . Smith said caves on Mars are an exciting find. "We can't say what's in the caves. It's just that they exist. It is hard to tell from orbit. Landers can follow up on these discoveries."
May 28, 07: A former Apollo astronaut blasted the U.S. space agency today in its handling of a Congressionally-mandated study on dealing with the threat of Near Earth Objects (NEOs) striking the Earth.
. . Russell "Rusty" Schweickart, the lunar module pilot for the Apollo 9 mission, called a recently issued NASA report on dealing with Earth-threatening asteroids, "flawed" and "not valid". "What we're talking about here is the possibility --in an evolutionary sense-- of a Control-Alt-Delete; a [computer-like] reboot of the evolutionary system that has already occurred many times on Earth", Schweickart said.
. . In any dealings with space rocks, there's need for early warning, a deflection capability and an international decision-making capability, Schweickart said. He reported that by 2019 asteroid watchers will have on the books upwards of 10,000 objects with a non-zero probability of impacting Earth. "The bottom line", he said, "is that in the next 10 to 12 years, we are going to, in all likelihood, have to make decisions...not because one of these things is going to hit us...but because several of them look as though they might hit us."
May 23, 07: Riding a rocket into space is like riding a controlled explosion, as astronaut Mike Mullane famously put it. JP Aerospace has a gentler plan –-lighter-than-air vehicles that lift people and cargo into orbit in three stages over the course of several days. First, a 175-foot-long Atmospheric Ascender rises to a construction platform at 140,000 feet –-the edge of space. Safe from balloon-shredding terrestrial winds, crew members assemble a larger, more buoyant craft and loft it [??] into orbit [on a rocket, I assume. But "more bouyant"?] This summer, the Rancho Cordova, California-based firm plans to float its Ascender prototype higher than ever, up to 100,000 feet.
May 23, 07: NASA is adding a docking ring to the James Webb Space Telescope (JWST) just in case a visit by astronauts aboard a future Orion Crew Exploration Vehicle is needed to complete deployment of the multibillion-dollar orbiting observatory.
May 22, 07: Dark-colored fungi devour radiation and convert it to fuel & edible biomass, researchers said, in a study that may offer applications from more efficient solar cells to feeding astronauts in space. The study may also explain why it feels so good to soak up the sun on the beach, the researchers report.
. . The fungi use the same compound as people do --melanin, the pigment that makes both skin and truffles dark. "Just as the pigment chlorophyll converts sunlight into chemical energy that allows green plants to live and grow, our research suggests that melanin can use a different portion of the electromagnetic spectrum -- ionizing radiation -- to benefit the fungi containing it", Dr. Ekaterina Dadachova of the Albert Einstein College of Medicine in New York said.
. . "It's pure speculation but not outside the realm of possibility that melanin could be providing energy to skin cells", said Dr. Arturo Casadevall, chair of microbiology and immunology at Einstein.
. . Their experiment was fairly simple. Casadevall was reading about fungi found growing in and around the reactor at Chernobyl, closed and heavily contaminated by an accident in 1986. So they grew some fungi, some types with melanin and others without melanin, and zapped them with gamma radiation. The dark fungi grew better when radiated.
. . Scientists have discovered life in recent years that does not rely on the sun --sulfur-eating bacteria and extremophiles that live deep beneath the sea or under Antarctic ice. Perhaps fungi can live in seemingly inhospitable places as well, said Casadevall, so long as there is some radiation.
. . His lab will test fungi against a range of electromagnetic radiation, from ultraviolet light to visible light. They will also test species of edible fungi, including mushrooms.
May 22, 07: Saturn's largest ring might appear solid when viewed from Earth, but closer inspection by NASA's Cassini spacecraft reveals it is composed of tightly packed clumps of particles in constant collision with one another. The research also suggests scientists have underestimated the total mass of Saturn's rings, which might actually be two or more times as massive than previously thought.
. . The observations confirmed that ring particles come together to form giant clumps called "self-gravity wakes" that can reach 30 to 50 meters across. If the clumps were farther from Saturn, they might amass to form a moon, scientists say. But because they are so close to Saturn, the clumps' different speeds around the planet counteract the gravitational attraction they feel for each other and stretch them out like taffy.
. . It was previously thought the ring particles crashed into one another about twice every hour. Instead, "at any given time, most particles are going to be in one of the clumps", Cowell said, "but the particles keep moving from clump to clump as clumps are destroyed and new ones are formed."
May 22, 07: The strongest evidence yet that ancient Mars was much wetter than it is now has been unearthed by NASA's Spirit rover. A patch of Martian soil kicked up and analyzed by Spirit appears to be rich in silica, which suggests it would have required water to produce.
. . Chemical analysis performed by the rover's robotic arm-mounted science instruments measured a composition of about 90% pure silica --a material commonly found in quartz on Earth-- for the bit of Martian dirt.
. . This discovery came about unexpectedly as the result of a mechanical failure. One of Spirit's six wheels no longer rotates, gouging a deep impression as it drags through soil. That scraping has exposed several patches of bright soil.
. . Spirit had previously found other indicators of long-ago water at the site, such as patches of water-bearing, sulfur-rich soil, alteration of minerals, and evidence of explosive volcanism.
May 22, 07: China's first Mars probe will be launched in October 2009 as part of a joint mission with Russia, say sources. During Chinese President Hu Jintao's visit to Russia in late March, the two governments signed an agreement to launch joint exploration of Mars and Phobos, the innermost and biggest of the red planet's moons.
. . Under the agreement, a Russian rocket will lift a Chinese probe, actually a satellite, and a Russian exploration vehicle --known as Phobos-Grunt-- to survey Mars and Phobos. The small Chinese satellite will explore Mars while the Russian craft will land on Phobos to explore the environment and take soil samples. The two vehicles will reach the orbit of Mars in 2010 more than 10 months after their launch.
May 21, 07: Roger Angel thinks big. Angel, a leading astronomer at the U of Arizona, is proposing an enormous liquid-mirror telescope on Luna that could be hundreds of times more sensitive than the Hubble Space Telescope.
. . Using a rotating dish of reflective liquid as its primary mirror, Angel's telescope would the largest ever built. LMT's have been built on Earth --the Large Zenith Telescope in British Columbia is the third largest telescope in North America-- but Luna's low gravity and lack of atmosphere would allow for a truly gigantic instrument.
. . Angel dreams of a 100-meter mirror, which would be larger than two side-by-side football fields and would collect 1,736 times more light than the Hubble. Even a 20-meter instrument, which is more likely in the near term, would be 70 times more sensitive than the Hubble and could detect objects 100 times fainter than those that will be seen with the James Webb Space Telescope, a next-generation orbiting observatory scheduled for launch in 2013.
. . Liquid telescopes cost 10 to 20 times less to build than polished aluminum mirrors of similar size, in part because they needn't be engineered to the same tolerances. And even the largest liquid mirrors don't require the sophisticated support structures that are needed to prevent solid ones from sagging under their own weight.
. . A lunar LMT would be free from the atmospheric distortion.
. . The light from the universe's most distant stars is intensely red-shifted, and the airless lunar deep-freeze would be ideal for infrared observation –-as would a liquid mirror: While they perform as well as conventional mirrors at visible wavelengths, liquid mirrors do even better in the infrared. Alas, the same low temperatures that would facilitate IR observation would also turn mercury, the liquid used in terrestrial LMTs, into a solid. So the greatest technical challenge for Angel's team lies in finding reflective liquids with low freezing points and vapor pressures –-liquids that would neither freeze nor evaporate into space.
. . That task fell to Ermanno Borra, a physicist and liquid-mirror pioneer at Laval U in Quebec who first made the case for a lunar LMT in 1991. Recently, Borra has been experimenting with metal liquid-like films, or MELFFs, that reflect light as effectively as aluminum.
. . Ultra-smooth air bearings and synchronous motors governed by crystal oscillators and optical sensors eliminated the vibration and unstable rotation that plagued early LMTs. (Air bearings wouldn't work on Luna, so Angel proposes using superconductor magnetic bearings instead.)
. . Since liquid mirrors cannot be tilted in order to track objects as they move across the sky, early efforts at liquid-mirror astrophotography generated streaks of light that quickly exited the field of view. [how about tracking targets thru a flat mirror aimed into the liquid one?]
. . The tracking problem was solved with a technique called drift-scanning, in the rotation of Luna is taken into account by software. Digitization also allows images from many nights' observation to be combined, resulting in extremely long cumulative exposure times.
May 21, 07: China plans to launch a lunar orbiter in the second half of 2007, in a first step towards a lunar probe, Xinhua news agency quoted the director of the National Space Administration as saying.
. . If the Chang'e I orbiter succeeds in orbiting Luna, the next step would be an attempt to land. Ultimately a moon rover would collect samples before returning to earth. Luna rover mission would be due in 2012.
May 16, 07: Slushy water geysers on Saturn's moon Enceladus might be powered by the grinding of ice sheets against one another and the periodic widening of rifts on the satellite's surface.
. . Results from two new studies support the idea that a process called "tidal heating" is responsible for plumes of water vapor and ice crystals recently observed spouting from the moon's unusually warm south pole.
. . Enceladus is a small gray-white world coated in ice. Its surface is pockmarked by craters and scoured by pale blue fractures resembling veins. Called "tiger stripes", these fractures mark the boundaries between enormous ice sheets that encase the planet like a shell.
. . NASA's Cassini spacecraft recently observed geysers erupting from the tiger stripes into space. The most active tiger stripes are clustered around a mysterious hot spot recently discovered on the moon's south pole. They found that ice sheets grinding against each other at tiger stripe fractures generate enough heat to melt some of the ice. The melted ice would sublimate into water vapor and float directly into space.
. . Because its orbit around Saturn is elliptical, the moon is closer to Saturn at some points of its orbit than others and the force of gravity it feels from the planet varies with distance. When Enceladus is closest to Saturn, gravity causes a bulge to form on the side of the moon facing the planet; the bulge shrinks as the moon moves farther away. Like a repeatedly bent paperclip, the constant motion on Enceladus generates friction and heat.
. . Nimmo's team also estimates the ice shell on Enceladus is at least 5 km thick and that a vast, deep ocean is tucked beneath it. "If the ice [shell] was coupled directly to rock, it can't roll around very much", Nimmo explained. "But if you put an ocean in between, the ice can move around much more and you can get more heating."
May 15, 07: An experiment aimed at finding ways to help astronauts adapt to life on Mars could end up helping insomniacs on Earth, researchers said.
. . They found that two 45-minute exposures to bright light in the evening could help people adjust to a Martian-style day, where the days are about 24 hours and 39 minutes long, or 24.65 hours.
. . During the experiment, they found a wider-than-expected variation in an internal system the human body uses to keep track of days and nights, and they believe their treatment might help people with certain disorders of this system.
. . This nearly 25-hour day is enough to throw most people into a state of jet lag, which Czeisler has shown interferes with the ability to learn, remember things, react quickly and to sleep. They said the natural range of circadian days in just their group was from 23.47 hours to 24.48 hour days --a full hour's difference.
. . They took blood from these volunteers every hour and found those people with the shorter internal clock released the sleep hormone melatonin four to five hours before their usual bedtimes, while those with unusually long internal days did not release melatonin until about an hour before bedtime.
. . Other research has shown that using a computer after dark, working in a brightly lit office or other exposure to bright light can mess up a person's internal clock, making it harder to fall asleep. So Czeisler's team tested the volunteers in a similar way, using two 45-minute exposures to bright light for 30 days. The volunteers successfully adjusted to the Martian-length day.
May 10, 07: The James Webb Space Telescope, intended to peer deep into the cosmos from an orbit beyond Luna, is progressing well in development and is on track for a planned June 2013 launch, officials said. It is not an exact replacement for the Hubble, as it sees in a different spectrum. The $4.5bn 'scope will take up a position some 1.5 million km from Earth, at Lagrange Point 2 (L2), an area of gravitational balance that keeps it in a Sun-Earth line. It will measure 24m long by 12m high and incorporate a hexagonal mirror 6.5m in diameter, almost three times the size of Hubble's, shaded from sunlight by a shield, enabling it to stay cold, increasing its sensitivity to infrared radiation. Three principal instruments will gather images of the Universe in the infrared region of the spectrum. It is expected to have a 10-year lifespan.
. . Until launch, the 17-year-old Hubble telescope will continue to do its work. Nasa plans to send astronauts on the space shuttle to service it in 2008.
May 7, 07: Given the choice, Russian cosmonauts would likely never come back to Earth. It is the part of their jobs they like the least.
May 8, 07: A robotic probe designed to touch and analyze Martian water for the first time is being prepared for launch at the Kennedy Space Center in Florida, officials said. The craft, known as Phoenix, is expected to land in the northern polar region of Mars and dig beneath the soil. Launch is scheduled for August 3 from Cape Canaveral.
. . Bolstered by evidence that Mars once had liquid surface water, scientists are keen to recover an actual sample to see if the materials for life exist. Upon reaching Mars in May 2008, the spacecraft is to land just as the winter ice begins to recede around the polar cap. Scientists expect the probe will touch down on newly exposed soil, but their true target lies just beneath the surface.
. . Among Phoenix's tools are devices to scoop and drill, photograph and chemically analyze soil and ice samples. Phoenix is a resurrection of spare parts and instruments from the unsuccessful Mars Polar Lander and Mars Surveyor 2001 Lander initiatives.
. . Polar Lander was lost as it attempted to touch down in December 1999. Mars Surveyor was canceled in the wake of Polar Lander's failure and the loss of a sister probe, Mars Climate Orbiter, two months earlier. NASA traced the failures to inadequate testing and oversights. A metric conversion error led to the orbiter's demise, for example.
May 8, 07: The Cassini spacecraft circling Saturn has returned images of immense rotating storms that appear to be the powerhouse behind the ringed planet's jet streams. Saturn's giant rotating storms --or eddies-- feed into the planet's swift jet streams, much like rotating gears can power a conveyor belt, by pumping them with energetic winds. It's exactly the opposite of what we thought prior to Cassini."
. . On Saturn, jet streams can blow 10 times faster than they do on Earth and reach speeds of up to 1,609 km per hour.
May 8, 07: A spinning web of electrified wire 50 km wide may become the spacecraft propulsion system of the future. A team from the Kumpula Space Center in Finland is proposing a huge electronic sail for spacecraft that may dramatically reduce journey times across the solar system. The giant sail, which would be twice the length of Manhattan, is made from about 100 wires spun up into a whirling disk. Electrified by an onboard, solar-powered electron gun, the negatively charged wires repel the positively charged protons of the solar wind, providing thrust.
. . The solar wind is a high-speed plasma stream blowing outward from the Sun. The average pressure of the solar wind is miniscule (a mere 2 nanopascals, or 0.2 grams of weight per square kilometer), which explains the need for such a large sail.
. . Because the wires, or tethers, are thinner than human hair, they can create a sail that is much larger than a solid surface --up to 50 km wide. "The most difficult challenge is posed by the tethers and the tether reels", says Jahnunen. "Manufacturing 25-km-long tethers thinner than human hair is an engineering challenge, as is development of the mechanics of the reel."
. . Results drawn from computer simulations indicate that in an average solar wind, a 200-kg spacecraft could achieve final speeds of up to 100 kms a second (or 1.9 billion miles a year), allowing a spacecraft to reach Pluto in less than five years. Because the electric sail needs no propellant or other consumables, it might also provide cheap transportation of raw materials in space. Now that the feasibility of the concept has been proven, a prototype could be built within two years, says Janhunen.
. . Winglee leads a U of Washington team developing a rival spacecraft propulsion system called the MagBeam, which provides thrust using directed plasma streams that push against a magnetic field carried by a spacecraft. The MagBeam is intended for short, quick journeys, such as from low-Earth orbit to the moon, or from Earth to Mars.
May 6, 07: A record: Europe's commercial launcher, the Ariane 5, put a two-satellite nine-ton payload in orbit.
May 4, 07: NASA's Spirit rover has stumbled upon evidence of an ancient volcanic explosion at "Home Plate", a plateau of layered bedrock near the rover's landing site in Gusev Crater. The finding lends more evidence to the idea that Mars had a watery past, and marks the first explosive volcanic deposit seen by Spirit or its rover twin.
. . Evidence shows the area near Home Plate is mostly basaltic rock --indicating water may have mixed with magma beneath the Martian ground. When basalt erupts, Squyres said, it's normally smooth-flowing lava and not blown outward. "One way for basaltic lava to cause an explosion is for it to come into contact with water--it's the pressure from the steam that causes it to go boom."
. . The explosive basalt isn't the only red flag for water. Another example is the high chlorine content of the rocks, which might indicate that basalt had come into contact with brine, or saltwater.
. . But one of the strongest pieces of evidence is a "bomb sag" on the lower slopes of the plateau. On Earth, bomb sags form when rocks eject skyward by a volcanic explosion and fall into soft deposits which deform as they land.
. . Spirit and Opportunity are in their fourth year of exploring Mars. As of April 26, Spirit had spent 1,177 sols, or Martian days, on the surface of Mars and had driven 7km, and Opportunity had spent 1,157 sols and driven 10.5 km.
May 3, 07: Using a fancy version of a common chef's trick, scientists have discovered that Mercury's core may be partially molten, making it a little more Earth-like than once thought.
. . Cooks [& you] can tell whether an egg is hard-boiled or raw by spinning it on a countertop. A raw egg will wobble. So apparently does Mercury. The oscillations were twice what they would expect for a completely solid body. Based on those calculations, the scientists are now 90 to 95% sure Mercury's core is at least partially molten. "Mercury is an extreme planet because it is made primarily of iron. The core occupies maybe 75 or 80% of the radius of the planet."
May 4, 07: Scientists in the US say that initial data from a new way of scanning Mars has shown up to half of the Red Planet's surface may contain ice. The new method of scanning for water offers vastly more accurate readings than before, they say.
. . The data could prove vital for the Phoenix Mars Mission which launches this August and which will put a lander on the surface to dig for ice. The deposits --far beyond the ice that is known to exist in the planet's North Pole-- could be so large that were they to melt, they would deluge the planet in water forming an ocean.
. . A robotic lander might have to work harder to dig for ice on some parts of Mars than others. New findings show underground ice depth can vary significantly on the Red Planet, being right at the surface in one spot but several feet down nearby. The research has implications for NASA's Phoenix mission, designed to drill down to sample the Martian ice.
. . Bandfield found the nature of the Martian topsoil determined how deep the ice was below it. Areas with many rocks at the surface "pump a lot of heat into the ground and increase the depth where you'll find stable ice." In contrast, dusty areas tend to insulate ice, allowing it to climb closer to the surface.
. . It was previously thought that Martian water ice was located at average depths of about 1 to 2 meters, but Bandfield's new study shows it can be found as close as 5 cm from the surface.
May 3, 07: Environmental satellites that monitor global warming are in jeopardy because of cost cuts, as military and human spaceflight programs get larger shares of the U.S. budget, a science policy expert said.
. . "Environmental research and development has been hit particularly hard over the last few years ... The satellite capability that's projected over the next few years looks pretty bleak", said Kei Koizumi. Budget cuts will mean that some existing satellites won't be replaced when they reach the end of their lifespans and some other planned satellite launches have been canceled.
. . Earth-observing satellites watch for oncoming storms and forecast daily weather as well as looking for signs of global warming and other phenomena. Weather forecasters who rely on their data would also be affected by any gaps in service.
. . This week, scientists using NASA's Aura satellite reported the Arctic ice cap is melting about three times faster than computer models suggested.
. . One example is the U.S. Climate Change Science Program, where funding dropped from $2 billion as recently as 2004 to $1.5 billion in the proposed 2008 budget, Koizumi said. His comments were in line with a statement released this week by the science association's board. "The network of satellites upon which the US and the world have relied for indispensable observations of Earth from space is in jeopardy", the board said. "Declines will result in major gaps in the continuity and quality of the data gathered about the Earth from space." The U.S. National Research Council came to the same conclusion in an earlier analysis.
May 1, 07: How do you get rid of the body of a dead astronaut on a three-year mission to Mars and back?
. . When should the plug be pulled on a critically ill astronaut who is using up precious oxygen and endangering the rest of the crew? Should NASA employ DNA testing to weed out astronauts who might get a disease on a long flight?
. . With NASA planning to land on Mars 30 years from now, the space agency has begun to ponder some of the thorny practical and ethical questions posed by deep space exploration. Some of these who-gets-thrown-from-the-lifeboat questions are outlined in a NASA document on crew health.
. . "As you can imagine, it's a thing that people aren't really comfortable talking about", said Dr. Richard Williams, NASA's chief health and medical officer. "We're trying to develop the ethical framework to equip commanders and mission managers to make some of those difficult decisions should they arrive in the future."
. . One topic that is evidently too hot to handle: How do you cope with sexual desire among healthy young men and women during a mission years long? Sex is not mentioned in the document and has long been almost a taboo topic at NASA. Williams said the question of sex in space is not a matter of crew health but a behavioral issue that will have to be taken up by others at NASA.
. . The agency will have to address the matter sooner or later, said Paul Root Wolpe, a bioethicist at the U of Pennsylvania who has advised NASA since 2001. "There is a decision that is going to have to be made about mixed-sex crews, and there is going to be a lot of debate about it", he said.
. . The document does spell out some health policies in detail, such as how much radiation astronauts can be exposed to from space travel (No more radiation than the amount that would increase the risk of cancer by 3% over the astronaut's career) and the number of hours crew members should work each week (No more than 48 hours).
. . Mars-bound astronauts will not always be able to rely on instructions from Mission Control, since it would take nearly a half-hour for a question to be asked and an answer to come back via radio.
. . Astronauts going to Luna and Mars for long periods of time must contend with the basic health risks from space travel, multiplied many times over: radiation, the loss of muscle and bone, and the psychological challenges of isolation. NASA will consider whether astronauts must undergo preventive surgery, such as an appendectomy, to head off medical emergencies during a mission, and whether astronauts should be required to sign living wills with end-of-life instructions.
. . The space agency also must decide whether to set age restrictions on the crew, and whether astronauts of reproductive age should be required to bank sperm or eggs because of the risk of genetic mutations from radiation exposure during long trips.
May 3, 07: The chief of Russia's space agency said that the US has rejected a proposal for the two countries to explore Luna together.
Apr 25, 07: The European Union is open to co-operation with the up-and-coming Indian and Chinese space industries on its Mars operations but it will maintain control over the mission, the European Space Agency said.
Apr 24, 07: Saturn's icy moon Dione may have much in common with its active sibling Enceladus, new research using Cassini data revealed. They modelled Dione's surface using digital elevation models (DEMs). Their results indicate volcanism has been a major force in shaping Dione's surface.
. . "We don't see giant shield volcanoes belching lavas", says Schenk. "Instead we see smooth plains with low crater densities." These plains are the hallmark of cryovolcanism, which manifests itself as an outpouring of icy liquids from a moon's interior. Dione's cryovolcanic plains are higher than the surrounding terrain, suggesting they may have been emplaced in a high viscosity flow similar to terrestrial glaciers sometime within the last 2 billion to 4 billion years.
. . Cryovolcanism requires a heat source to drive liquids to the surface. At present, the mechanism for this heat engine is not fully understood but the two leading contenders are radioactive decay and gravitational flexing.
. . Dione has a radius of 560 km and orbits Saturn every 2.73 days from 377,400 km away. Its average surface temperature is minus 186 C. Enceladus has a radius of 250 km and orbits Saturn every 1.37 days from 238,020 km away. Its average surface temperature is minus 201 Celsius.
Apr 23, 07: The rise and fall of species on Earth might be driven in part by the undulating motions of the Solar System as it travels through the disk of the Milky Way, scientists say.
. . Two years ago, scientists at the U of California, Berkeley found the marine fossil record shows that biodiversity-the number of different species alive on the planet-increases and decreases on a 62-million-year cycle. At least two of the Earth's great mass extinctions-the Permian extinction 250 million years ago and the Ordovician extinction about 450 million years ago-correspond with peaks of this cycle, which can't be explained by evolutionary theory.
. . Now, a team of researchers at the U of Kansas (KU) have come up with an out-of-this-world explanation. Their idea hinges upon the fact that, appearances aside, stars are not fixed in space. They move around, sometimes rushing headlong through galaxies, or approaching close enough to one another for brief cosmic trysts.
. . In particular, our Sun moves toward and away from the Milky Way's center, and also up and down through the galactic plane. One complete up-and-down cycle takes 64 million years --suspiciously similar to Earth's biodiversity cycle.
. . The KU researchers independently confirmed the biodiversity cycle and have proposed a novel mechanism by which the Sun's galactic travels is causing it.
. . Scientists know the Milky Way is being gravitationally pulled toward a massive cluster of galaxies, called the Virgo Cluster, located about 50 million light years away. Adrian Melott and his colleague Mikhail Medvedev, both KU researchers, speculate that as the Milky Way hurdles towards the Virgo Cluster, it generates a so-called bow shock in front of it that is similar to the shock wave created by a supersonic jet.
. . "Our Solar System has a shock wave around it, and it produces a good quantity of the cosmic rays that hit the Earth. Why shouldn't the galaxy have a shock wave, too?" Melott said. The galactic bow shock is only present on the north side of the Milky Way's galactic plane, because that is the side facing the Virgo Cluster as it moves through space, and it would cause superheated gas and cosmic rays to stream behind it, the researchers say. Normally, our galaxy's magnetic field shields our solar system from this "galactic wind." But every 64 million years, the solar system's cyclical travels take it above the galactic plane.
. . Cosmic rays are also associated with increased cloud cover, which could cool the planet by blocking out more of the Sun's rays. They also interact with molecules in the atmosphere to create nitrogen oxide, a gas that eats away at our planet's ozone layer, which protects us from the Sun's harmful ultraviolet rays.
. . Richard Muller, one of the UC Berkeley physicists who co-discovered the cycle, said Melott and his colleagues have come up with a plausible galactic explanation for the biodiversity cycle. Muller and Robert Rohde also speculated that our solar system's movement through the galactic plane was behind the cycle, but the pair could not conceive of any reason why conditions on the north and south side of the galactic plane should differ.
. . Richard Bambach, a paleontologist at the Smithsonian Museum of Natural History who was not involved in the study, said he is excited the biodiversity cycle has been independently confirmed, but cautions the galactic hypothesis is still in the early stages of formulation.
. . "It's a first-step hypothesis", Bambach said. "It's an interesting idea, but we're a long way from knowing if that is really why biodiversity changes." For one thing, scientists have yet to discover a bow shock around the Milky Way, though such shock waves have been found around other galaxies.
Apr 23, 07: Scientists unveiled today some of the first 3-D images of the violent electrical storms that rage within the Sun's atmosphere.
. . In the new images, the electrified loops and charged particles that blow from the Sun's surface seem to come to life. Besides the oohs-and-aahs, the results will help scientists track powerful solar eruptions and predict how they could affect Earth, similar to hurricane-tracking.
. . In particular, the observatories have their eyes on coronal mass ejections, which are violent eruptions that carry massive amounts of electrically charged gas called plasma from the Sun's atmosphere. Once unleashed, these plasma clouds race away from the Sun at up to a million miles per hour.
Apr 20, 07: British engineers are designing a Lunar landing mission that would also test key technologies to take to Mars. The MoonTwins concept would put two probes on the lunar surface --one at each pole-- to do science experiments.
. . Esa plans eventually to go to the Red Planet to retrieve rocks for analysis on Earth, and Luna is seen as a good place to develop the know-how. The agency expects to fly a demonstrator in the period 2015 to 2018.
. . The two spacecraft would be launched on the same rocket but would make their own way. In lunar orbit, they would practise coupling --a maneuver that would be required on any multi-stage Mars mission-- before making their way down to Luna's surface. "They won't have a roving capability, but it's likely they would be able to do a short ascent, perhaps to hop to a new location", said Dr Healy.
. . At least one of the MoonTwins would be targeted at what could become a key location for human habitation --the so called Peak of Eternal Light. This is close to the rim of Shackleton Crater at the south pole. The peak experiences near-continuous sunlight, making it an excellent location to site solar power units. The crater itself has the opposite conditions --it is in permanent shadow. "It's a good place to go because there could be hydrogen there. It's an open question as to whether that hydrogen is in the form of water-ice or if it is simply solar wind hydrogen --elemental hydrogen in the lunar soil."
Apr 20, 07: Japan is set to launch its first lunar orbiter this summer, but exploring Luna is just part of the mission. The other goal is to catch up with China, the new leader in Asia's space race.
. . Japan's space agency JAXA announced last week that the much-delayed SELENE probe will be launched in August aboard an H-2A rocket, the mainstay of Japan's space program. JAXA says the SELENE project is the largest lunar mission since the U.S. Apollo program. It involves placing a main satellite in orbit at an altitude of about 60 miles and deploying two smaller satellites in polar orbits. The mission is a stepping stone in Japan's plan to more aggressively pursue space objectives —-including a lunar landing and, possibly, manned missions in space.
. . This year, China also plans to launch a probe that will orbit Luna. Earlier this month, they launched a Long March 3-A rocket that sent a navigation satellite into orbit as part of its effort to build a global positioning system. Japan, meanwhile, has met with one setback after another.
. . Other Asian nations are joining in the race. In 2000, South Korea broke ground on a $277 million rocket launch site. It plans, with Russian help, to put a small satellite in orbit next year. India is hoping to launch its Chandrayaan-1 moon mission this year or next, though its technological prowess and $700 million space budget remain well behind its ambitions. China spends at least $1.2 billion on space-related projects and the U.S. about $16 billion.
Apr 20, 07: The frequency of the sound waves in our sun's atmosphere is below the human hearing threshold. While humans can make out sounds between 20 and 20,000 hertz, the solar sound waves are on the order of milli-hertz--a thousandth of a hertz.
. . They found that explosive events at the Sun's surface appear to trigger acoustic waves that bounce back and forth between both ends of the loops, a phenomenon known as a standing wave. The acoustic waves can be extremely energetic, reaching heights of tens of miles, and can travel at rapid speeds of 45,000 to 90,000 miles per hour. "These [explosions] release energy equivalent to millions of hydrogen bombs."
. . The finding could help explain why the corona is so hot. While the surface is a steamy 5,538 degrees C, plasma gas in the corona soars to more than 100 times hotter. "How can the atmosphere above the surface of the Sun be hotter if nuclear fusion happens inside the Sun?" von Fay-Siebenburgen said. If astronomers can get a clearer picture of what's going on inside these magnetic loops in the Sun's atmosphere, they have a better chance of finding the answer.
. . Another recent study using images from Hinode's telescope revealed twisted magnetic fields along the Sun's surface, which store huge amounts of energy. The magnetic fields can snap like a rubber band; when they do, they might release energy that could heat up the corona or power solar eruptions and coronal mass ejections, the researchers say.
Apr 20, 07: Like a jiggled jar of mixed nuts, shaking on the near-Earth planetisimal Itokawa is sorting loose rock particles on its surface by size, causing the smallest grains to sink into depressions, a new study suggests.
. . Researchers analyzed images of a mix of boulders and gravel, called regolith, covering the surface of Itokawa. The images, taken by the Japanese Hayabusa spacecraft in 2005, revealed that some areas were coated with fine particles and appeared smooth, while others regions looked bumpy, as if the planetisimal suffered an intense case of acne.
. . The new findings suggest seismic activity of some kind is occurring on Itokawa, a small planetisimal only 500 meters in diameter. What might have rattled it is still an open question. One hypothesis is that smaller planetisimals occasionally strike Itokawa and shake the space rock up. Because of its diminutive size, even tiny impacts could send Itokawa into a tremor. Another idea is that Itokawa might occasionally fly close enough to the Earth, where our planet's gravity could jostle it.
. . Perhaps the most intriguing hypothesis: Scheeres ties Itokawa's periodic shaking to the YORP effect, in which sunlight provides a small nudge that can speed up or slow down its rotation. Computer simulations suggest radiation from the Sun is having the latter effect on Itokawa, causing it to spin slower and slower. Working backward, Scheeres reasons Itokawa must have spun faster in the distant past.
. . Wind the clock back 200,000 years, Itokawa might have spun around so fast that its head and body parts became separated and orbited around each other. Occasionally, the two orbiting segments might have smacked back together again, like beating cymbals, and the vibrations might have jostled loose particles on Itokawa's surface around.
Apr 18, 07: British scientists are planning to see whether a Star Trek-style deflector shield could be built to protect astronauts from radiation. They argue that magnetic shields could be deployed around spacecraft and on the surfaces of planets to deflect harmful energized particles. Scientists hope to mimic the magnetic field which protects the Earth.
. . To create the deflector shield around a spacecraft or on the surface of a planet or moon, scientists need to generate a magnetic field and then fill it with ionized gas called plasma. The plasma would held in place by a stable magnetic field.
. . As energetic particles interact with the plasma, energy is sapped away from them and they slow down. "You don't need much of a magnetic field to hold off the solar wind. You could produce the shield 20-30 km away from the spacecraft."
. . A permanent Moon base, of the type Nasa plans to build, could be buried under lunar soil to protect the occupants and equipment from space radiation. But inhabitants will still be vulnerable when venturing outside in their spacesuits.
. . The idea for the shields draws on technology pioneered in experimental nuclear fusion reactors. This represents a reversal of that technology: "We want to use the same technique to keep an object in the middle away from plasma that's on the outside."
Apr 18, 07: Tiny "smart" devices that can be borne on the wind like dust particles could be carried in space probes to explore other planets, UK engineers say. The devices would consist of a computer chip covered by a plastic sheath that can change shape when a voltage is applied, enabling it to be steered. The particles could use wireless networking to form swarms. Computer chips of the size and sophistication required to meet the challenge already exist.
. . Smart dust could be packed into the nose cones of planetary probes and then released into the atmospheres of planets, where they would be carried on the wind. For a planet like Mars, smart dust particles would each have to be the size of a grain of sand. By applying a voltage to alter the shape of the polymer sheath surrounding the chip, dust particle could be steered towards a target, even in high winds.
. . "We envisage that most of the particles can only talk to their nearest neighbors but a few can communicate at much longer distances. In our simulations, we have shown that a swarm of 50 dust particles can organize themselves into a star formation, even in turbulent wind." The ability to fly in formation would allow the processing of data to be spread, or "distributed" between all the chips, and a collective signal to be beamed back to a "mothership".
. . Smart dust particles would have to carry sensors. But current chemical sensors would be too large to be carried on particles the size of sand grains. The scientists hope the pace of miniaturization will make smaller sensors available in coming decades. "We have a lot of obstacles to overcome before we are even ready to physically test our designs."
. . Many other applications have been proposed for smart dust. One idea is to use particles to gather information on battlefields. Another idea involves mixing the particles into concrete to internally monitor the health of buildings and bridges.
Apr 13, 07: Japan is building upon its past successes in space to forge a range of initiatives, from disaster warning systems, probes to Mercury, Venus and Jupiter, as well as conduct an aggressive lunar exploration.
Apr 10, 07: New images from a Venus-orbiting satellite reveal the planet's atmosphere is much more dynamic than previously thought and that conditions can change in a matter of hours.
. . The chaotic atmosphere of Venus has long baffled scientists. Winds speeds are so high that clouds can be ferried around the entire planet in only four Earth-days in what scientists call a "super-rotation." Yet Venus, a rocky world, takes 243 Earth-days to make one complete rotation around its axis.
. . Venus Express, the first dedicated mission to study the stormy atmosphere of our sister planet since the Magellan spacecraft more than 15 years ago, arrived at Venus in April 2006.
. . Since it takes so long for Venus to complete one rotation on its axis, the day side has a long time to heat up while the night side sits in cold darkness. The Sun heats up the thick Venusian atmosphere on the day side and creates convective cells where masses of warm air upwell and create local disturbances and regional winds.
. . 'We know that in the past there has been an intense volcanic activity, but it is not sure when this stopped, if it did', he said. 'We [also] know that about 800 million years ago there [was] a complete resurfacing of the planet surface, possibly catastrophic, but what was the cause? What about the global atmospheric dynamics and energetic balance of the planet?
. . The thick atmosphere --largely of sulfuric acid gas-- is about 95 times greater than Earth's and would "crush" a human. [fry, too!]
Apr 6, 07: Prototype Satellites Demonstrate In-Orbit Refueling: Despite a rocky start, two unmanned spacecraft have succeeded in their first autonomous satellite refueling demonstration while orbiting high above Earth. It successfully pumped vital hydrazine fuel into its NextSat counterpart as part of Scenario 0-1, the first in a series of increasingly challenging tests. "ASTRO transferred just under 14 kg of hydrazine to the NextSat client."
. . In addition to refueling demonstrations, ASTRO is also designed to perform tasks such as autonomous undocking, proximity operations and re-docking, as well as use its robotic arm to install a battery on NextSat.
Apr 5, 07: A recently-observed supernova is making some astrophysicists doubt prevailing theories for how stars die.
. . The massive star, located in galaxy UGC 4904 about 77 million light-years from Earth, threw off a huge amount of material on October 20, 2004. This star, which may have been what's known as a Luminous Blue Variable (LBV), was mistaken for a supernova, as LBV's often are. In fact, some observers refer to them as "supernova imposters."
. . Then, in the fall of 2006, the star exploded into a full supernova, much sooner than expected. Dubbed Supernova 2006jc, the dying star's blast wave apparently reached the shell of drifting material released in the earlier outburst in mere hours.
. . The wave heated the ejected gases to millions of degrees, sparking X-ray emissions of an intensity and duration never before detected. NASA's Swift satellite recorded X-rays brightening from the supernova for an unprecedented 100 days. All previously observed supernovae have initially appeared bright in X-rays before quickly turning invisible.
. . The supernova's blast wave ran into a slow-moving shell of material, presumed to be the upper layers of the star ejected two years earlier.
Apr 4, 07: Shifting dust storms on Mars might be contributing to global warming there that is shrinking the planet's southern polar ice caps, scientists say. [BUT: totally diff reason! You may've read the crap that tries to use this to nay-say our warming.]
. . Computer simulations similar to those used to predict weather here on Earth show that the bright, windblown dust and sand particles affects Mars' albedo-the amount of sunlight reflected from the planet's surface. It could also potentially explain how global dust storms are triggered there.
. . Across the past two decades, the model showed the surface temperature of Mars has increased by about 0.65 degrees Celsius. 'That magnitude of change is comparable to what we've estimated for global warming on Earth over the last 100 years', said study participant Paul Geissler of the USGS.
. . The model also found that winds have strengthened over regions with the lowest albedo. The researchers think all these events are related and have proposed a mechanism by which lower albedo drives wind circulation, creating even lower albedo. They think it works like this: In regions where winds blow away dust, the exposed dark ground absorbs sunlight and heats up; some of this heat is transferred into the atmosphere and heats up the air. Just like on Earth, the imbalance in the atmosphere's heat increases wind circulation above those regions. This leads to a positive feedback effect. The wind speeds could ramp up until a threshold is reached, at which point conditions are ripe for a dust storm that swamps the entire planet
. . Scientists had struggled to explain the shrinkage and have blamed it on everything from fluctuations in the Sun's output to natural variations in the planet's orbit and tilt.
. . On earth, CO2 traps infrared radiation which can affect global climate. This a phenomenon is known as the greenhouse effect. Fossil fuel emissions add to the problem. On Mars, it's the red-tinged dust.
Apr 4, 07: The Global Positioning System, relied on for everything from navigating cars and airplanes to transferring money between banks, may be threatened by powerful solar flares, a panel of scientists warned.
Apr 1, 07: Scientists in Shanghai are developing a nuclear-powered lunar rover for the country's first unmanned mission to Luna in 2012, newspapers reported. The six-wheeled vehicle has been under development for four years. The 5-foot-high, 440-pound rover is designed to transmit video in real time, dig for and analyze soil samples, and produce three dimensional images of the lunar surface.
. . In photographs, the rover appeared similar to NASA's unmanned Spirit and Opportunity Mars explorers. However, unlike the rechargeable lithium ion batteries used by those rovers, the Chinese model will eventually run on a nuclear power source to ensure a constant energy supply. With an average speed of 100 meters per hour, it can negotiate inclines and has automatic sensors to prevent it from crashing into other objects.
Apr 2, 07: A Mars-orbiting satellite recently spotted seven dark spots near the planet's equator that scientists think could be entrances to underground caves. The football-field sized holes were observed by Mars Odyssey's Thermal Emission Imaging System (THEMIS) and have been dubbed the seven sisters. The potential caves were spotted near a massive Martian volcano, Arisa Mons. Their openings range from about 100 to 250 meters wide, and one of them, Dena, is thought to extend nearly 130 meters beneath the planet's surface.
. . "Caves on Mars could become habitats for future explorers or could be the only structures that preserve evidence of past or present microbial life ", said Glenn Cushing of Northern Arizona U, who first spotted the black areas in the photographs.
. . A project here on Earth aims to refine the visual and infrared techniques THEMIS used to find the Martian caves and to also develop robots that can one day enter the caverns and explore them. If the caves have a relatively simple structure --like lava tubes, which are caves carved by flowing magma and are relatively simple and straight-- a rover-type robot might work, Cabrol said. "I would doubt that a rover, equipped as they are now, would do a good job in a cave" with a more complicated geometry.
Mar 28, 07: NASA is preparing to test an inflatable structure that might one day be used to establish an outpost on Luna.
. . The pumped-up structure sits poised for tests at the agency's Langley Research Center in Virginia. The inflatable structure is made of multilayer fabric and looks like an ungainly white robot with legs. The main unit is 12 feet in diameter and 18 feet tall. It has a volume of about 1,600 cubic feet and is connected to an airlock, also inflatable. The two spaces are essentially pressurized cylinders, connected by an airtight door. The biggest advantage of expandable structures is they can be compressed into a small volume for launch.
. . NASA envisions a lunar outpost as being a testing ground in preparation for a longer journey to Mars.
Mar 28, 07: China and Russia will mount a joint effort to explore Mars and one of its moons in 2009, Chinese state media reported following an agreement to boost cooperation between the two ambitious space powers. A Russian rocket will lift a Chinese satellite and Russian exploration vehicle to survey Mars and Phobos, the innermost and biggest of the moons.
Mar 27, 07: It’s been years since NASA last heard from either of its two Pioneer probes hurtling out of the Solar System, but scientists are still debating the source of an odd force pushing against the outbound spacecraft. "The Pioneer spacecraft conducted the largest ever gravitational experiment that humanity attempted to test Newton's Law, and it failed."
. . Dubbed the Pioneer Anomaly, the unexplained force appears to be acting against NASA’s identical Pioneer 10 and 11 probes, holding them back as they head away from the Sun. Whether that force stems from the probes themselves, something esoteric like dark matter, or some new facet of physics or gravity, remains in doubt. But a wealth of newly recovered data and telemetry, spanning decades of observations by both Pioneer 10 and 11, may yield the final answer, after about a year of analysis.
. . Shapiro said that the number of actual instances in which oddities like the Pioneer Anomaly have opened pathways to fundamentally new physics are rare, and that ongoing studies may yet yield a conventional explanation.
. . Launched in 1972 and 1973, Pioneer 10 and 11 are both billions of miles from Earth as they zoom out of the solar system in opposite directions. As of Feb. 6, Pioneer 10 was about 92.12 astronomical units (AU) from Sol.
. . The discrepancy found that Pioneer 10 and 11 were each about 400,000 km closer to Sol than they should be, according to the current understanding of gravity. Isaac Newton described gravity as a force that weakens with distance, and the Pioneer probes are speeding out of the solar system at about 48,280 km per hour.
. . Researchers want to determine whether heat from Pioneer probes’ electronics or two nuclear power sources —known as radioisotope thermal generators (RTGs)— could be emitting infrared photons that then smack into the spacecraft’s dish-like main antenna, causing a recoil effect that Turyshev likened to sunlight striking a solar sail. Analysis and modeling of how the Pioneer 10 spacecraft emits heat from various sources, including its RTG, found that they account for between 55% and 75% of Pioneer Anomaly, said Gary Kinsella.
. . Another possible explanation rests in the mass of the Milky Way galaxy, which –-when taken to account-– yielded the exact acceleration change for Pioneer 10 as that observed. While he found that the technique did not yield a specific direction for the acceleration, it may shed some insight into the anomaly and warrants further study, Belbruno added.
. . He is also keeping a close watch on NASA’s New Horizons probe, which may one day show signs of the anomaly as it heads out beyond Pluto’s orbit after 2015, but only if the mystery force is found to be an actual effect.
Mar 27, 07: One of the most bizarre weather patterns known has been photographed at Saturn, where astronomers have spotted a huge, six-sided feature circling the north pole. Rather than the normally sinuous cloud structures seen on all planets that have atmospheres, this thing is a hexagon [rufly]. The hexagon is nearly 25,000 km across. Nearly four Earths could fit inside it. The thermal imagery shows the hexagon extends about 100 km down into the clouds.
. . The honeycomb-like feature has been seen before. NASA's Voyager 1 and 2 spacecraft imaged it more than two decades ago. Now, having spotted it with the Cassini spacecraft, scientists conclude it is a long-lasting oddity. "This is a very strange feature, lying in a precise geometric fashion with six nearly equally straight sides." The hexagon appears to have remained fixed with Saturn's rotation rate and axis since first glimpsed by Voyager 26 years ago.
. . At Saturn's south pole, Cassini recently spotted a freaky human eye-like feature that resembles a hurricane.
Mar 24, 07: The Cassini spacecraft's radar sweep of Saturn's largest moon Titan in January revealed a portion of what appears to be a 180 km diameter impact crater. If its impact origin is confirmed, it would only be the fourth such crater discovered on Titan, a surprisingly small number. 'With radar having examined about 10% of Titan's surface, we have only three definite craters, and perhaps a half-dozen probables.'
. . Titan's thick nitrogen atmosphere hinders the formation of impact craters less than about 20 km in diameter, because smaller space rocks burn up before they reach the surface. It is likely that a combination of burial in sand, erosion by methane or obliteration by the cold hand of cryovolcanism is responsible.
. . Such organics --when exposed to water in the lab-- have been seen to form the prebiotic molecules essential to the formation of proteins and DNA.
Mar 23, 07: Strangely, astronomers don't know how long a day is on Saturn, because they can't get a firm footing on the problem given the giant planet's gaseous nature. So they have long relied on radio measurements of the ringed planet's magnetic field to help estimate the length of the day. But that doesn't really work either, they realized, so estimates have remained loose. Now the scientists at least have a better handle on this aspect of the problem.
. . Geyser activity from Saturn's small moon Enceladus weighs down the big planet's magnetic field so much that the field rotates more slowly than Saturn itself, new observations reveal. The moon is a mere 500 km wide.
. . Meanwhile, measurements revealed last year that Saturn's day has gotten about six or eight minutes longer --now roughly 10 hours and 47 minutes-- since the 1980s, when measured by the Voyager missions. Nobody suspects the trend to continue forever (meaning the days would just get longer and longer at such a rapid rate), but they also don't know what's going on.
Mar 21, 07: X-ray images taken from a new international spacecraft show that the Sun's magnetic field is much more turbulent than scientists knew, NASA reported.
Mar 19, 07: Scientists are investigating the possible threat posed to astronauts by inhaling lunar dust.
. . A study suggests the smallest particles in lunar dust might be toxic, if comparisons with dust inhalation cases on Earth apply. Teams hope to carry out experiments on mice to determine whether this is the case or not. Nasa has set up a working group to look into the matter ahead of its planned return to Luna by 2020.
. . "The medical doctors are interested in things that are less than about three microns. So we did some particle size determinations and discovered that a very large portion of lunar soil is potentially dangerous, approximately 1-3% of the total soil by weight."
. . Most particles in lunar soil should get coughed up, or moved out of the lungs by specialised hairs called cilli. But any particles smaller than about 2.5 microns will stick in lung tissue. When dust is deposited in the lungs, inflammation occurs. Ultimately, scar tissue called a fibroid grows around the particle. This scar tissue replaces cells which facilitate the exchange of oxygen for CO2 in the lungs.
This is the process at work in the condition silicosis --an occupational hazard in mining, quarrying and foundry work - and asbestosis, which results from inhaling asbestos fibers. It also occurs in bronchitis and as a consequence of smoking.
Mar 18, 07: Scientists studying pictures from Nasa's Odyssey spacecraft have spotted what they think may be seven caves on the surface of Mars. The candidate caves are on the flanks of the Arsia Mons volcano and are of sufficient depth that their floors mostly cannot be seen through the opening.
. . The possible discovery of caves is significant. They may be the only natural structures capable of protecting primitive life forms [AND astronauts!] from micrometeoroids, UV radiation, solar flares and high energy particles that bombard the planet's surface.
The spacecraft spotted what seemed to be vertical "skylight" entrances to caves below the surface. There is a sheer drop of between about 80m and 130m or more to the cave floors below.
. . The cave entrances are between 100m and 252m wide. Only minimum depths are known: the researchers calculated they must extend between 73m and 96m (240-315ft) below the surface. However, in one image taken of Dena by the Mars Odyssey Camera, a floor can be seen. Using the data, the authors calculated that this cave must extend 130m below the surface.
Mar 15, 07: The scientists behind the Beagle 2 mission, which was lost on Mars in 2003, want to send a nearly identical spacecraft to Luna. They say Beagle 2's science instruments are ideal for assessing whether humans could exploit lunar resources when NASA returns in 2020. A Beagle could be sent to Luna on its own, or attached to a lunar rover. It could determine whether deposits of hydrogen, water-ice and hydrocarbons are trapped in Luna's cold regions.
Mar 16, 07: The Wave of Yesterday's Future. The Urey: Mars Organic Oxidant Detector has been designed by NASA-funded researchers to look for life on Mars. This "life detector" will check for life's essential molecules at incredibly small concentrations. Urey will also distinguish between amino acids made by biological and non-biological processes.
. . The device is named after Harold Urey, who received the 1934 Nobel Prize in chemistry; Dr. Urey is also known for a 1953 experiment with Stanley Miller in which it was shown that a lightning-like discharge in a test tube full of methane, hydrogen, ammonia and water could produce amino acids.
. . Every form of life on Earth has proteins assembled from chains of amino acids. However, amino acids can be made both by living organisms and by non-biological processes. The presence of amino acids alone do not prove the existence of life.
. . It turns out that non-biological processes create a 50/50 mix of left- and right-handed versions of the molecules. Living things on Earth, however, make and use left-handed amino acids almost exclusively. Clever Urey the life detector will be looking for the ratio between left- and right-handed molecules.
. . The European Space Agency has chosen Urey to be part of the payload for the ExoMars rover planned for launch in 2013. The rover will grind Martian soil to a fine powder and then deliver it to a suite of instruments, including Urey.
Al Globus --National Space Society
. . We may live in orbit long before settling Luna or Mars, and there may always be far more space settlers in orbit than on any planet or moon. Orbital settlements are huge spacecraft, big enough for many thousands to live in comfortably, that provide radiation protection, a breathable atmosphere, nearly self-sufficient life support, and that rotate to provide something that feels much like Earth-normal gravity at the rim. Why do I think orbital settlements will precede and vastly outperform those on planets and moons?
. . Getting back and forth to orbit is far easier than getting to Luna or Mars, which is why we've had space stations circling Earth for thirty years and have yet to see the first base on Luna, much less on Mars.
. . Planetisimals in orbit near Earth have vast quantities of valuable metals --one small Earth-approaching planetisimal has been valued at $20 trillion! The single largest planetisimal, Ceres, provides enough materials to build orbital space colonies with 1g living area equal to at least a hundred times the surface area of Earth. Orbital space settlement will be the greatest expansion of life ever. Orbital space settlement in this solar system can provide space for ten trillion or more human beings living in excellent conditions.
. . All of life has evolved under the force of Earth's gravity. The strength of that force plays a major role in the way our bodies work, including the development and maintenance of human bone and muscle. The potential effects of lower Lunar or Martian g levels are unknown, but a large orbital space settlement can be rotated to have nearly any pseudo-gravity desired. Children raised in orbital settlements should have no problem visiting Earth.
Mar 16, 07: Scientists have produced a global geological map of Jupiter's moon Europa, which has been proposed as a destination for a future space mission. Interest in Europa has been fuelled by indications that a liquid water ocean lurks beneath its outer shell of ice. The mapping effort will help build a geological history of the enigmatic moon and target future explorations.
. . Europa's surface is young, active and smooth with few craters. But it is criss-crossed by a network of fractures, thought to be where the icy shell has been pried apart by the tidal forces of Jupiter.
. . The work will look at what instruments a spacecraft should take, what orbits would be required for the mission and how the probe might operate in the Jovian moon's harsh radiation environment. After the four teams report back in the summer, officials at Nasa HQ in Washington DC will evaluate the case for a mission and decide which to carry forward.
. . In addition, an international consortium is preparing a Europa mission proposal to be submitted under the European Space Agency's (Esa) Cosmic Visions program.
. . A "dream" concept for the exploration of Europa would be a robotic probe, perhaps powered by radioactive decay, that could melt through the ice and explore the ocean beneath. But this would pose formidable technical challenges: the ice shell could be about 20km thick.
. . Just getting to Europa is tough --a spacecraft would have to pick up lots of speed and then brake hard to reach it. In addition, the harsh radiation environment gives a spacecraft orbiting the moon a lifetime of just 66 days, according to an Esa feasibility study.
Mar 15, 07: Scientists are puzzling over new Mars rover data that reveal soil packed with sulfur and traces of water. The finding could be evidence of an evaporated spring or volcanic deposits from ancient gas vents.
. . While digging around in Mars' Columbia Hills last year, NASA's Spirit rover unearthed bright white and yellow material hidden beneath a layer of normal reddish soil. The material is sulfur-rich and consists of sulfate salts associated with iron and possibly even calcium.
Mar 15, 07: A spacecraft orbiting Mars has scanned huge deposits of water ice at its south pole so plentiful they would blanket the planet in 12 meters of water if they were liquid, scientists said. It covers an area larger than Texas. Some of the new info even hints at the possible existence of a thin layer of liquid water at the base of the deposits.
. . The deposits, up to 3.7 Km thick, are under a polar cap of white frozen CO2 and water, and appear to be composed of at least 90% frozen water, with dust mixed in.
. . The same techniques are being used to examine similar ice deposits at the Martian north pole. A preliminary look at those data indicated the ice deposits in at the north pole are comparable to those at the south pole.
. . If we expect to find existing life on Mars. we need to go to a location where water is available", Plaut said. He said it appears perhaps 10% of the water that once existed on Mars is now trapped in these polar deposits. Other water may exist below the planet's surface or perhaps some was lost into space through the atmosphere.
Mar 15, 07: A Nasa scientist has proposed using the replacement to the space shuttle to land on a near-Earth planetisimal. The Crew Exploration Vehicle (CEV) is due to make its maiden flight in 2014, with the eventual aim of ferrying astronauts to and from Luna. The space shuttle is due to be retired in 2010 to make way for the CEV. Orion will ride atop a single five-segment solid rocket booster.
. . Dr Paul Abell said such a mission could help efforts to protect against an planetisimal on course to hit Earth. A mission would be expected to take longer than a journey to Luna, but would require less energy.
. . Currently, the project is envisaged to include two or three crew members and last a total of 90-180 days. The plan would be to visit a planetisimal in the sub-kilometer size range, perhaps about the size of planetisimal Itokawa (535m) which was visited by Japan's Hayabusa spacecraft. The CEV, which Nasa has named Orion, would spend approximately 7-14 days there. The spacecraft would effectively orbit the body, while astronauts visited the surface to carry out experiments.
Mar 14, 07: Shiny, gray space boulders floating in the outskirts of the solar system are the remnants of an ancient fiery collision involving two massive objects, the larger of which was nearly the size of Pluto, scientists say. This rocky goliath could one day cross the orbit of Neptune and become one of the biggest comets ever known. The finding marks the first "collisional family" detected in the Kuiper Belt and provide new insights about the solar system's murky history.
. . The parent body of the new collisional family is thought to be 2003 EL61, one of the largest objects in the Kuiper Belt. It currently is football-shaped, with a diameter of about 1,500 km, but was probably spherical and 20% larger before the collision, the researchers say. Pluto is about 2,300 km wide.
. . 2003 EL61 is thought to have collided with an object in its distant past that was roughly half its size and traveling at nearly 7,000 mph, causing it to spin end-over-end every four hours. It spins so fast that it has pulled itself into the shape of an American football. The amount of energy generated by the blast would have equaled about 10 billion nuclear bombs.
. . It happened perhaps as far back as 4.5 billion years ago, when the Kuiper Belt was much more crowded than it is now and objects were more likely to bump into one another. The impact spawned at least seven other rocky objects --and likely more-- with diameters ranging from 10 to 400 km. The researchers lumped the scattered objects into a family based on their matching gray color and evidence of surface water ice derived from spectral analyses. 'None of the rest of the Kuiper Belt is as shiny and pristine.' "When we tried to find out what it was made of, we found that it was mostly rock. Nothing else out there is made out of rock. Everything else out there is made out of ice."
. . They found a family of five objects that likely are the offspring of this giant spinning rock. The objects were found in an area of the solar system beyond Neptune where no other planetisimal families have been found. The disk-shaped region is about 2.8 billion to 4.6 billion miles from the sun.
. . About 35 other collisional families are known, but they are all located in the planetisimal belt.
Mar 13, 07: A NASA spacecraft has found evidence of huge seas, likely filled with liquid methane or ethane, in the high northern latitudes of Saturn's moon Titan. One of the seas is larger than any of the Great Lakes in North America and possibly only slightly smaller than the Caspian Sea, which lies between Russia and
Iran and is the largest lake on Earth. (Lakes are typically landlocked but the Caspian Sea was called a sea when it was initially discovered because it tasted salty.)
. . Cassini's camera imaged a large, irregular feature stretching 1100 km long. The very dark features, detected by a radar instrument on NASA's Cassini spacecraft, are located near Titan's north pole, and one of them measures at least 100,000 square km.
Mar 12, 07: Scientists believe heat from radioactive decay inside a tiny, icy Saturn moon shortly after it formed billions of years ago may explain why geysers are erupting from the surface today. The Cassini spacecraft last year beamed back dazzling images of Yellowstone-like geysers spewing from a warm section on Enceladus, raising the possibility that the moon, which has an overall surface temperature of about minus-330 degrees, may have an internal environment suitable for primitive life.
. . However, scientists have been stumped by the origin of Enceladus' interior heat. Now a new model suggests ancient radioactive decay played a key role in shaping the moon's warm south pole region.
. . According to the theory, Enceladus formed some 4.5 billion years ago by the mixing of ice and rock containing radioactive isotopes of aluminum and iron. Over a period of several million years, the rapid decay of the isotopes produced a burst of heat that resulted in a rocky core enclosed by an ice sheet. Over time, the remaining decomposition in the core further warmed and melted the moon's interior. If confirmed, the model suggests Enceladus possesses the necessary ingredients to support life —-a stable heat source, organic materials and liquid water.
. . Last year, another research team published a study that cast doubt on the existence of water near Enceladus' surface. That study suggested that buried ice clathrates —-not liquid water-— were responsible for releasing the plumes through a tectonic shift in the crust. Clathrates are lattice-like molecular structures that trap other types of molecules.
Mar 12, 07: The European and US space agencies are moving ahead on their next major missions to explore the Solar System. Nasa has begun to choose a destination for a "flagship" robotic venture along the lines of Cassini-Huygens, which has been exploring Saturn and its moons. It is considering four targets: the Jupiter system, Jupiter's moon Europa, and Saturn's moons Enceladus and Titan.
. . Europa, Titan and Enceladus are also among the destinations expected to be proposed under the European Space Agency's (Esa) "Cosmic Visions" program. Perhaps a mission to return soil from a near-Earth planetisimal, and a probe might survey the saturnian moon's surface by balloon.
. . Scientists have long wanted to burrow through Europa's ice to the ocean beneath, but John Zarnecki says that, for now, this may be too ambitious. He favors a two-stage approach, in which an orbiter is sent first, possibly with ground-penetrating radar, followed later by a lander capable of penetrating the ice. "Others say we should go for a lander and a penetrator straight away, but I don't know how feasible that is, financially and technically. Landing on Europa is very demanding, you have to brake very hard on approach."
Mar 12, 07: DARPA (Defense Advanced Research Projects) who have just launched their first satellite repair bots into space. Dubbed ASTRO, the repair bots are designed to patch up other satellites without any human guidance, instead they rely on GPS and laser sensors. Once docked with the ailing satellite, ASTRO uses a 10-foot robotic arm to fill the satellite with fuel and make repairs.
Mar 7, 07: Groundwater once bubbled up from beneath the surface of Mars to form transient, shallow pools before evaporating and leaving behind thick layers of salty minerals, a new computer model suggests.
. . The new model provides an alternative explanation for sulphate-rich 'evaporite' deposits discovered on Mars' Meridiani Planum, hailed by some scientists as the desiccated remains of an ancient ocean covering the planet's Northern Plains. It also suggests Mars in its early history had a globally connected groundwater system.
Mar 7, 07: Built by Texas-based Stone Aerospace, the autonomous underwater vehicle Deep Phreatic Thermal eXplorer (DEPTHX) will begin a second round of dives this week to explore the depths of La Pilita, a 115-meter deep geothermal sinkhole in Mexico. They follow a series of successful tests dives to shakedown the vehicle's autonomous navigation and mapping capabilities.
. . Stone and his team are priming DEPTHX to take the ultimate dive down El Zacaton, a water-filled geothermal sinkhole --or cenote-- in Mexico known to reach depths beyond 282 meters, though its true bottom has not been detected by either human divers, robots or sonar. That expedition is slated for May.
. . The research is part of a $5 million NASA study to develop technology that could one day allow a waterborne explorer to probe the vast unknown ocean though to lurk beneath the miles-thick crust of ice covering Europa. The cracked, icy Jovian moon has been billed one of the solar systems' best hunting grounds for ET organisms.
. . 2.5-meters wide, weighing in at a hefty 1.3 tons, DEPTHX's design keeps it neutrally buoyant in water, and built to dive to a depth of about 1,000 meters. [In Europa, the very low gravity means the water pressure rises very slowly with depth.]
. . The brass ring of DEPTHX's guidance system is its Simultaneous Localization and Mapping (SLAM) system, navigation software designed to allow the robot to autonomous take its sonar and other sensor readings to build reliable and useful 3-D maps of unexplored terrain. "As it builds the map, it can actually use that map as it moves around." "The ... trick beyond what we've already done is to give it the ability to sniff out environmental variables, gradients in the environment's chemistry, that would suggest something is going on."
. . DEPTHX carries a probe-like appendage capable of retrieving solid samples during dives and contains space for up to five two-liter water samples. The robot also sports cameras to scan for color changes in rock walls and an onboard microscope to detect moving cells, a hallmark of living microorganisms. It can also go to the deep lake bottoms below Antarctic ice.
Mar 5, 07: NASA officials say the space agency is capable of finding nearly all the planetisimals that might pose a devastating hit to Earth, but there isn't enough money to pay for the task so it won't get done. The cost to find at least 90% of the 20,000 potentially hazardous planetisimals and comets by 2020 would be about $1 billion.
. . These are planetisimals that are bigger than 460 feet in diameter — slightly smaller than the Superdome in New Orleans. They are a threat even if they don't hit Earth because if they explode while close enough — an event caused by heating in both the rock and the atmosphere — the devastation from the shockwaves is still immense. The explosion alone could have with the power of 100 million tons of dynamite, enough to devastate an entire state, such as Maryland.
. . The agency is already tracking bigger objects, at least 3,300 feet in diameter, that could wipe out most life on Earth, much like what is theorized to have happened to dinosaurs 65 million years ago. But even that search, which has spotted 769 planetisimals and comets —-none of which is on course to hit Earth-- is behind schedule. It's supposed to be complete by the end of next year.
Feb 28, 07: Future Mars rovers could be equipped with a new instrument that sifts through Martian soil for chemical signs of life.
. . Biomedical students at the Johns Hopkins U School of Medicine have won a $750,000 NASA grant to design a prototype for a so-called mini mass spectrometer that can probe Mars core samples for evidence of biological molecules such as proteins and nucleic acids, of which DNA is made, for the European Space Agency's ExoMars mission, scheduled to launch in 2013. "What a mass spectrometer can identify are chemical signatures of life or the building blocks of life that may have at some point existed on the red planet."
Feb 24, 07: Astronomers have made rare images of the heart of a popular comet and revealed jets of gas spiraling thousands of miles into space. Comet McNaught has been called the Great Comet of 2007 for the show it put on first in the Northern Hemisphere and then south of the equator. The ball of ice and dirt hung frustratingly close to the Sun, however, so many skywatchers never got a good look.
. . Scientists found sodium in the comet's emissions, something rare in a comet. the nucleus of the comet is probably less than 25 km in diameter.
Feb 22, 07: NASA is studying the potential of future cooperation with the suborbital tourism firm Virgin Galactic on a variety of fronts, agency officials announced. A Memorandum of Understanding between the U.S. space agency and Virgin Galactic will allow NASA to eye future collaboration with the space tourism firm on the development of spacesuits, spacecraft heat shields, hybrid rocket motors and hypersonic vehicles.
. . Virgin Galactic is building a fleet of five SpaceShipTwo spacecraft to carry paying passengers on suborbital spaceflights based first out New Mexico's Spaceport America in 2008 and followed by flights from Kiruna, Sweden in 2012. Designed by aerospace veteran Burt Rutan, the SpaceShipTwo vehicle is an evolved version of SpaceShipOne, which won the $10 million suborbital Ansari X Prize competition for reusable, privately-built crewed spacecraft in 2004.
Feb 21, 07: A spacecraft that aims to land on a comet may also establish whether there is a thin ring of debris around Mars this week. The Rosetta probe will use Mars' gravity to pick up speed on a mission that will reach its climax in 2014. In seven years' time, the probe will enter orbit around a comet, releasing a small lander on to its icy nucleus.
. . But during a very close flyby, Rosetta will look for a scattering of dust from Mars' two moons, Phobos and Deimos. "Theory tells us there should be a faint ring, and Hubble has come close to finding the evidence."
. . Comets are thought to be about 80% water, and Rosetta's landing vehicle will examine the amount of deuterium, a heavy form of hydrogen, present in its ices. The investigations will help test the theory that water was brought to the Earth by comet impacts during its early development.
Feb 20, 07: At the start of a solar cycle, sunspots-regions on the Sun marked by cooler temperatures and intense magnetic activity-tend to appear near the poles and move towards the equator as the cycle concludes.
. . Scientists were therefore surprised when Ulysses, a joint European Space Agency (ESA) and NASA spacecraft currently embarking on its third tour around the Sun since launch in 1990, spotted intense solar storms near the Sun's south pole.
. . Ulysses also found that the Sun's south pole is currently cooler than its north pole. This is a reversal from 10 years ago, when the northern polar coronal hole was about 7 to 8 percent lower than the southern one. Coronal holes are like bald spots on the Sun: they are regions in the Sun's upper atmosphere, called the corona, where there is less heated gas than average. During solar minimum, coronal holes are mainly found at the Sun's polar regions; during solar maximum, they can be located anywhere. 'This implies that the asymmetry between north and south has switched with the change of the magnetic polarity of the Sun.'
. . The Sun's magnetic field consists of a north pole, where the field flows out of the Sun, and a south pole, where the field re-enters. During solar maximum, when the Sun's activity is at a peak in its 11-year cycle, the poles exchange places.
Feb 17, 07: A planetisimal may come uncomfortably close to Earth in 2036 and the UN should assume responsibility for a space mission to deflect it, a group of astronauts, engineers and scientists said. A draft UN treaty to tackle any heading for Earth is to be drawn up this year.
Feb 15, 07: Experts have been wary of planetisimals since they came to the conclusion that one of them ended the Age of the Dinosaurs 65 million years ago. Scientists such as Stephen Hawking warn that their relatively close proximity presents grave dangers to humankind. But others consider planetisimals the next landscape for scientific discovery. "Anything robust enough to go to the moon is going to be robust enough for lots of missions."
. . Astronaut Edward Lu said that plans under study include landing & retrieving rock samples for return to Earth before 2020. And at NASA's Ames Research Center, lab chief Simon "Pete" Worden, a longtime advocate of such exploration, has set aside $10 million for designing small spacecraft that could visit them.
. . The International Astronomical Union has given identifying numbers to nearly 150,000, & about 5,000 are discovered every month. A mix of sand piles, dust balls, metal-rich rocks and burned-out comets, they mostly congregate in the planetisimal belt between Mars and Jupiter.
. . Closer to home, NASA has, as of November, tracked 855 potentially dangerous Near-Earth rocks. These pass within about 30 million miles of Earth, with a diameter of approximately 1 km or larger. Astronomers regard that size as the point at which impact with Earth would threaten civilization.
. . Says Binzel: "There are literally hundreds of Near-Earth planetisimals that are probably easier to reach than the moon, in terms of the propellant you need to go there and back." That's because they have hardly any gravity. So fuel costs for blasting out of each one's "gravity well" are minimal. Eros, a hefty near-Earth planetisimal, some 30 km long by 12 across, has such light gravity that a person could toss a baseball off its surface and into orbit. In comparison, a rocket needs a 5,370 mph escape velocity to leave Luna.
. . Morrison will describe a Near-Earth Asteroid Trailblazing (NEAT) probe, low-cost landers designed to flit among nearby planetisimals, scouting their surfaces, at a March American Institute of Aeronautics and Astronautics meeting.
. . "Landing on one would be more like docking with the international space station than a moon landing", says astronomer Daniel Durda of the Southwest Research Institute in Boulder, Colo. Astronauts would most likely "swim" over the surface of a planetisimal, he says, so lightly do things fall on a typical one, which essentially has zero gravity.
. . Once in orbit and gravitationally bound to a dangerous planetisimal, the space tractor would gently fire its thrusters to slowly "tug" the threatening rock onto a safer trajectory. Apophis, for example, would require a one-ton tug to orbit the planetisimal for a month before its 2029 close pass by Earth to put it onto a safer path.
. . Some, like Eros, appear to be fairly solid objects, based on their gravity, albeit intensely dust-covered ones. The slowly-rotating Mathilde, which the NEAR-Shoemaker probe flew past in 1997, appears three times less heavy than its size would indicate, suggesting it may have hollow spaces. And the planetisimal Itokawa is just a rubble pile, a surprise that explains the 2005 failure of Japan's Hayabusa probe to land there.
. . Broadly speaking, inhabitants of the main planetisimal belt between Mars and Jupiter are thought to come in three flavors: dark carbon-rich "carbonaceous" ones that make up about 75% of the total, iron-rich "metallic" planetisimals, and fairly bright "silicaceous" planetisimals built from a mix of iron and sand.
Feb 15, 07: A Mars-orbiting spacecraft has spotted a subterranean natural plumbing system that might have ferried water beneath the surface of the red planet in the distant past.[note: NOT hollow, like lava tubes, which wuda been useful for habitation, & protection from radiation & meteors.]
. . New images taken by the HiRISE camera on NASA's Mars Reconnaissance Orbiter (MRO) show hills and plateaus with alternating layers of dark and light colored rocks in Candor Chasma, one of several canyons that make up Valles Marineris, a sprawling Martian rift valley that is longer than the contiguous US and up to seven times deeper than the Grand Canyon in places.
. . Cutting like a vertical scar across these light and dark bands in Candor Chasma are a series of linear cracks surrounded by 'halos' of light-colored bedrock. They suggest that liquid flowing through the fractures deposited iron-rich or clay-like minerals in the rock. The minerals would act like cement to strengthen the layers of rock and also bleach it a lighter color. Over millions of years, wind stripped away the top layers of surface rock, exposing the subsurface and its plumbing system to the light of day.
. . The linear cracks, called joints, are about a meter wide and range from several hundred meters to several km in length. How the joints formed is still a mystery, but once formed, they would have provided a conduit for flowing liquid, the researchers speculate.
. . Similar processes are known to occur on Earth. Veins of gold and silver in rock, for example, are formed when water rich in the dissolved forms of these elements flows through cracks and finally deposit the metals as bright streaks in the rock.
. . By being underground, the 'fluid can remain in place for a longer period of time', Okubo said. 'That will allow for the geochemical reactions to occur more thoroughly and more profusely through the rock, perhaps giving rise to habitable oases within the protected subsurface for any biologic activity to occur.'
. . Philip Christensen, a leading Mars researcher at Arizona State U, said the team's explanation for the joints is very plausible, but points out that the liquid that once flowed through the cracks might also have been volcanic magma. Molten magma flows like liquid and can also alter the color of surrounding rocks, Christensen said. It looks as if 'fluid was injected into these cracks. The question is what was the fluid?
. . Christensen added, however, that there are no large volcanoes in the Candor Chasma region photographed by the MRO, so 'water moving through those fractures is probably more likely than volcanic material.'
Feb 15, 07: Roger Launius said humans are destined to become a multi-planetary species, but that word may take on a whole new meaning as time evolves. Given that there will be the first child born on Luna, as well as Mars, will that person be a Homo sapien, he asked. Could the differences of gravity, radiation exposure mean those children would be unable to return to Earth?
. . "I think that's problematic", Launius said, and in some respects, might this be an evolutionary road not unlike that taken by amphibian creatures that departed their water world to become land creatures. "There is the possibility of the evolution of human species into something different", Launius said. He and fellow space researcher, Howard McCurdy of The American U in Washington, have authored a book on the subject to be published later this year.
. . One area where all spaceflight visionaries of the past failed to make meaningful predictions was in the rapidly advancing capabilities of robotics and electronics, Launius said. For example, when noted science fiction/fact writer, Arthur C. Clarke, envisioned geosynchronous telecommunications satellites in 1945, he believed that they would require humans working on board a manned space station because he thought it would be necessary to keep changing the vacuum tubes!
. . Projecting hundreds of years into the future, Launius said he believed that it is likely humans will evolve in ways that cannot be fathomed today, into a form of species perhaps tagged Homo sapiens Astro.
Feb 9, 07: Mars' moon Phobos could be the target for a technology trial that would seek to return rock samples to Earth. A UK team is developing a concept mission that aims to land a spacecraft on the potato-shaped object and grab material off its surface. These small rock fragments would then be dispatched to Earth in a capsule.
. . "It is being seen as a technological demonstrator for an eventual Mars sample return."
. . The British satellite manufacturer Astrium is proposing to test the required technologies on the low-gravity target of Phobos first. "It would be a three-year mission. We're looking at a 2016 launch." Whoever is chosen may well have to watch the Russians give it a go first. They are currently working on a project known as Phobos-Grunt, which could fly as early as 2009.
. . The UK Phobos concept has a number of challenging steps, all of them capable of killing the mission if a single element goes wrong. It is envisaged that a "mothership", powered by an ion engine, would fly into orbit around Mars where it would release a lander craft down on to the surface of the moon. This robot vehicle might do some in-situ experiments but its main task would be to core, drill, or scoop up surface "soil" into a sealed vessel. Some 200g would be enough.
. . Then, it would lift off from Phobos using chemical thrusters to attempt to dock with, or be captured by, the passing mothership. If that succeeds, the sample vessel would be transferred across and packaged inside an additional bio-secure sealed-container ready for the trip home. Close to Earth, this capsule would be jettisoned into the atmosphere to make a hard landing; it would need no parachute assistance.
. . One of the moon's most notable features is the system of grooves that cross its surface. These are assumed to be the result of collisions with rocks blasted off the surface of Mars by space impacts. "So, with this mission, you could get two for one."
Feb 8, 07: Icy particles ejected from a geyser on Saturn's moon Enceladus are blanketing other moons in reflective dust and ice, making them unusually bright, a new study suggests. Researchers measuring the reflectivity, or 'albedo' of several Saturnian moons found that four of them --Mimas, Tethys, Dione and Rhea-- were much brighter than estimates based on past measurements.
. . All four moons have ancient, geologically inert surfaces, so their unusual brightness surprised scientists. Other moons in the solar system with high albedo have active water and ice geysers that rain reflective ice particles onto their surfaces.
. . One thing all four Saturn moons do have in common, however, is that they are embedded in Saturn's E-ring, a faint ring made up of microscopic particles of ice and dust. The ring is so faint that scientists didn't discover it until about 30 years ago, and when they did, they noticed it was always brightest near Enceladus. This observation led many scientists to speculate that Enceladus was somehow supplying the material in the ring.
. . This idea was bolstered two years ago when NASA's Cassini spacecraft found evidence of active geysers and water volcanoes on Enceladus' south pole. Scientists now think that some of the particles ejected from these steamy sprinklers escape the moon's gravity and float into space. Saturn's gravity then ropes in the particles to form the E-ring.
. . According to a new theory, particles from Saturn's E-ring --supplied by Enceladus-- are crashing into the other moons at speeds of more than 36,000 km/h, embedding in the moons' surface and giving them an icy, reflective sheen.
. . Of the material that comes out of Enceladus as plume, only 1% makes it into the E-ring. The rest falls back to the surface of Enceladus as snow or rain
. . A rare celestial alignment that occurred on the night of Jan. 13, 2005, when the Earth, sandwiched between the Sun and Saturn's moons, traversed the entire solar disk. This heavenly arrangement gave astronomers on Earth 12 hours to measure the albedo of seven of Saturn's 11 moons with a precision impossible at any other time.
Feb 2, 07: A mammoth cloud half the size of the contiguous United States and spotted on Saturn's moon Titan might be what's filling up lakes discovered there last year, scientists say.
. . Imaged by NASA's Cassini spacecraft on Dec. 29, 2006, the cloud is about 2,400 km in diameter and engulfs Titan's entire north pole. It only recently became visible, emerging from a shadow as winter turns to spring on the moon. Cassini spotted partially filled lakes on Titan's north pole last summer. Scientists speculated that methane rains down onto the moon's surface to form lakes and then evaporates to form clouds, in what they called the 'methane-ologic cycle.' [stedda hydro-logic...]
. . The Titan cloud system comes and goes with the seasons. A season on the Saturn moon is equivalent to about seven Earth years [same as Saturn, as it's tipped at the same angle]. It may shift down to Titan's south pole as the seasons change.
Feb 2, 07: Scientists are scrambling to find an alternative landing site for a long-armed robot set to launch this summer on a mission to dig into Mars' icy north pole to search for signs of primitive life.
. . Three sites are clustered around the north pole, which is believed to have a huge amount of ice just below the surface. A site dubbed Green Valley is located within a shallow valley and looks the most secure, Smith said.
. . The probe has a robotic arm that can drill trenches as deep as 1M to search for water-ice beneath the surface. The spacecraft will test the chemistry of the soil and ice. Scientists hope it will yield clues to the geologic history of water and determine whether microbes existed in the ice.
Jan 30, 07: Neptune may be escorted in its orbit by thousands of planetisimal objects, perhaps more than exist in the entire "asteroid" belt. So far, five of these enigmatic bodies, known as Trojans, have been found at one of Neptune's Lagrange points. These are places where the gravity of a planet and that of the Sun interact to create an area of gravitationally stability.
. . Jupiter's Lagrange regions are home to legions of Trojans, and around 2,000 cluster at these gravity graves along Jupiter's orbit 60 degrees ahead and 60 degrees behind the gas giant. Lagrange points exist in any two-body system.
. . The first Neptune Trojan was discovered in 2001 as part of the NASA-funded Deep Ecliptic Survey at the Lagrange region 60 degrees ahead of Neptune (5 billion km --that's 15,000 times the distance from Earth to Luna!). A further three between 60 and 140 km in diameter and shaded a pale red color have since been identified.
. . There would be swarms of Trojans accompanying Neptune, perhaps up to twenty times more than at Jupiter [prob'ly 'cause Sol has little gravitic influence at that distance]. The sheer number of Trojans Neptune is thought to harbor reveal that these objects are an established part of Neptune's entourage, dating back to shortly after the planet's formation.
. . In 2014, we may get the opportunity to see a Trojan up close, courtesy of the New Horizons spacecraft currently en-route to Pluto. "If a Neptune Trojan could be found which the New Horizons spacecraft could image, it would be one of the highlights of the mission."
. . New Horizons will pass 60 degrees behind Neptune [5 billion km away... outa sight!] through the trailing Lagrange region known as 'L5' where no Trojans have yet been identified. "We are attempting to discover possible Neptune L5 Trojans, but because of the high background star confusion, it will be a tough task for the next several years."
Jan 29, 07: Cholera cases have surged to "alarming" levels in Angola after deadly floods left thousands of people without clean drinking water and access to sewage facilities, aid workers said.
Jan 29, 07: The last refuge for Martian life, if it exists, might be deep below the planet's surface and beyond the reach of any currently planned missions, according to a new study. After mapping cosmic radiation levels at various depths on Mars, researchers have concluded that any life within the first several yards of the planet's surface would be killed by lethal doses of cosmic radiation.
. . Unlike Earth, Mars is no longer protected by a global magnetic field or thick atmosphere. As a result, the planet has been vulnerable to radiation from space for billions of years. "Even the hardiest cells we know of could not possibly survive the cosmic radiation near the surface of Mars for that long."
. . Dartnell and his team developed a radiation dose model that calculates how much solar and galactic radiation Mars is subjected to. They tested three surface soil scenarios and calculated particle energies and radiation doses on the surface and at various depths underground. From this, they calculated the length of time that the hardiest known cells on Earth could survive.
. . The researchers estimate that life could survive for long periods of time about 7.5 meters beneath Elysium's ice. However, this is still beyond the range of any currently planned missions. The only mission that will come close, Dartnell said, is ExoMars, a European rover slated for launch in 2013. ExoMars will be equipped with a drill that can dig about 2 meters for samples.
. . Other potential sites to dig for life are young craters, the researchers say. The exposed rock in craters is denser than the ice that covers much of the planet, and it provides better shielding against space radiation than ice. The problem is that the subzero temperatures on Mars' surface makes it extremely difficult for cells to repair radiation damages that do occur or to divide. The cells would be frozen solid and held in stasis and the radiation damages would accumulate, until the point where they're killed off, Dartnell said.
. . Another good candidate for finding extant Martian life is new gullies recently discovered by Mars Global Surveyor, the researchers say. Evidence suggests the gullies might have flowed with water within the last five years, possibly ferrying underground cells to the surface.
. . Subterranean microbes have been discovered two miles and deeper beneath Earth's surface. Furthermore, those bacteria used the planet's internal heat, in the form of radioactive elements like uranium and potassium to convert water molecules into useable energy.
Jan 25, 07: New findings suggests the missing atmosphere of Mars might be locked up in hidden reservoirs on the planet, rather than having been chafed away by billions of years' worth of solar winds as previously thought.
. . Combining two years of observations by the European Space Agency's Mars Express spacecraft, researchers determined that Mars is currently losing only about 20 grams of air per second into space. Extrapolating this measurement back over 3.5 billion years, they estimate that only a small fraction, 0.2 to 4 millibars, of CO2 and a few cm of water could have been lost to solar winds during that timeframe.
. . According to the "warm and wet early Mars" model, liquid water once flowed on the red planet's surface. Evidence from channels and gullies recently spotted on Mars suggest the water layer might have been more than half a mile deep in places. For Mars to keep that much water in liquid form, the planet must have had a much higher atmospheric temperature, which scientists think was made possible by a strong greenhouse effect in the planet's past.
. . Mars' atmosphere must have been between 1 to 5 bars to maintain that kind of greenhouse effect, scientists think. But Mars' atmospheric pressure today is only a small fraction of that-about 0.008 bars, or about 0.7% of the average surface pressure at sea level on Earth.
. . Where the atmosphere went is still unclear, but the authors speculate that it might still be contained somewhere beneath the Martian surface.
Jan 24, 07: Scientists trying to find out where all the water on Mars went ruled out one culprit --new measurements show the Sun did not blow it away. They measured ions --charged particles-- being blown off the planet by the solar wind, itself a stream of charged particles. Very little oxygen or CO2 was blown off the planet during the year they measured it.
. . "Mars was once wet but is now dry, and the fate of its ancient CO2 atmosphere is one of the biggest puzzles in Martian planetology," they wrote in their report. It seems fairly clear to experts that the dusty red planet was once covered with lakes, oceans and perhaps rivers.
. . There is CO2 ice, but very little --much less than there must have been in the warm atmosphere that would have been needed to hold the water in place millions of years ago. "The escape rate is low, and thus one has to continue searching for water reservoirs and CO2 stores on or beneath the planetary surface and investigate other escape channels."
. . One other idea is an asteroid or some other large object hit Mars in the distant past and literally knocked off its atmosphere and large bodies of water.
Today, the Moon is on average 385,000 km away. It's being pushed away from Earth by 4 cm per year and our planet's rotation is slowing. If left unabated, Luna would continue in its retreat until it would take bout 47 days to orbit the Earth. Both Earth and Luna would then keep the same faces permanently turned toward one another as Earth's spin would also have slowed to one rotation every 47 days.
. . The Sun's mutation into a red giant provides a huge stumbling block to Luna's getaway. 'The density and temperature both increase rapidly near the apparent surface (photosphere) of the future giant Sun,' Willson explained. As the Earth and Moon near this blistering hot region, the drag caused by the Sun's extended atmosphere will cause Luna's orbit to decay. Luna will swing ever closer to Earth until it reaches a point 18,470 km above Earth, a point termed the Roche limit. 'Reaching the Roche limit means that the gravity holding it [Luna] together is weaker than the tidal forces acting to pull it apart', Willson said.
. . Luna will be torn to pieces and every crater, mountain, valley, footprint and flag will be scattered to form a spectacular 37,000-km Saturn-like ring of debris above Earth's equator. The new rings will be short-lived. Theory dictates they'll eventually rain down onto Earth's surface.
. . If the Sun as a red giant sloughs off enough material before Earth evaporates, our planet will be revealed from its stellar cocoon Moon-less. Sol turns eventually into a stellar corpse called a white dwarf Sun, fading to black over the ensuing trillions of years.
. . Alternatively, if the swelling Sun loses 20% of its mass prior to it reaching our vicinity, both Earth and Luna could be spared incineration and remain together facing each other for eternity. The actual outcome remains a theoretical uncertainty because no red giant star has been observed during this crucial phase.
Jan 18, 07: An unusual dwarf planet discovered in the outer Solar System could be en route to becoming the brightest comet ever known --in a few centuries. Professor Mike Brown has calculated that the object could be due a close encounter with the planet Neptune. If so, Neptune's gravity could catapult it into the inner Solar System as a short-period comet.
. . 2003 EL61 is a large object; it is as big as Pluto along its longest dimension. But it is extremely unusual: spinning on its axis every four hours, it has developed an elongated shape. 2003 EL61 is apparently composed of rock with just a thin veneer of water-ice covering its surface. Other Kuiper Belt Objects (KBOs) contain much more water-ice.
. . Neptune's gravitational force could either sling the icy rock ball into the inner Solar System as a comet, out into the distant Oort Cloud region, or even into interstellar space.
. . Some time early in its history, it was smacked, edge on, by another large KBO. This broke off much of 2003 EL61's icy mantle, which coalesced to form several satellites. As expected, the satellites seem to be composed of very pure water-ice. Professor Brown suggested that some of 2003 EL61's mantle may already have made it into the inner Solar System as cometary material. The oblique impact also caused 2003 EL61 to spin rapidly.
. . "Mercury got hit by a large object early in the Solar System. It left mostly a big iron core, with a little bit of rock on the outside."
Jan 14, 07: Japan's space agency has recommended scrapping its first moon mission after more than a decade of delays, a spokeswoman said, in the latest blow to the country's beleaguered space program.
Jan 10, 07: Britain could send its first un-manned mission to the moon by 2010 to study the lunar surface and find the best site for humans to inhabit.
Jan 10, 07: NASA has selected a pair of Mars missions for further study for a 2011 flight opportunity. The U.S. space agency announced this week that it had selected competing mission proposals from two Boulder, Colo.-based institutions to spend the next nine months and $2 million refining their concepts in advance of selecting one of the missions in late 2007 for full development.
. . NASA's next Mars Scout mission. The chosen mission would have to launch by 2011 at a cost of no more than $475 million. The two finalists were selected from more than two-dozen proposals the agency received last summer.
Jan 7, 07: Two NASA space probes that visited Mars 30 years ago may have stumbled upon alien microbes on the Red Planet and inadvertently killed them, a scientist theorizes in a paper.
. . The problem was the Viking space probes of 1976-77 were looking for the wrong kind of life and didn't recognize it, the researcher said. In the '70s, the Viking mission found no signs of life. But it was looking for Earth-like life, in which salt water is the internal liquid of living cells. Given the cold dry conditions of Mars, that life could have evolved on Mars with the key internal fluid consisting of a mix of water and hydrogen peroxide, said Dirk Schulze-Makuch, author of the new research.
. . That's because a water-hydrogen peroxide mix stays liquid at very low temps (-68 degrees Fahrenheit), doesn't destroy cells when it freezes, and can suck scarce water vapor out of the air.
. . The Viking experiments of the '70s wouldn't have noticed alien hydrogen peroxide-based life and, in fact, would have killed it by drowning and overheating the microbes, said Schulze-Makuch. He points to an Earth bug called the bombardier beetle that produces a boiling-hot spray that is 25% hydrogen peroxide as a defense weapon.
. . Schulze-Makuch acknowledges he can't prove that Martian microbes exist, but given the Martian environment and how evolution works, "it makes sense."
Jan 4, 07: Images shot last summer by NASA's Cassini spacecraft provide the strongest evidence yet that Titan, a saturnian moon and one of the most Earth-like celestial bodies in the solar system, is dotted with a multitude of liquid lakes.
. . Instead of water, however, the Titan lakes are likely filled with methane, and possibly even ethane, organic compounds that are gases on Earth but liquid on the frigid surface of Titan. "It's going to behave like water", Stofan said about liquid methane. "It's transparent just the way water is. So if you were standing by the shoreline, you would be able to see down to whatever pebbles or gunk that was on the bottom."
. . Titan is the only moon in the solar system to have a dense atmosphere with thin layers of methane and nitrogen clouds--a setup similar to that of early Earth. Atmospheric methane is destroyed by sunlight over time and must constantly be renewed. Scientists thus speculated that lakes or even oceans of methane might exist on, or just beneath, the moon's icy surface and that evaporation from these liquid bodies was replenishing the atmosphere. The first confirmation of this thinking came last July when Cassini's radar spotted more than 75 large, dark patches around the surface of the moon's northern pole.
. . The clincher that the patches were liquid lakes came from looking at the surrounding terrain. Some of the patches appeared to be fed by sinuous channels, or "rivers", some more than 100 km long. Others appeared to be contained within rimmed circular depressions, similar to crater lakes or volcanic calderas on Earth.
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