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In the summer of 1969 I was ten years old. On a warm night in July my parents woke me up around midnight to watch (on our black and white TV) Neil Armstrong walk on the moon. Apollo 11 was launched from the Earth on July 16th, landed on the Moon on the 20th, and returned to Earth on July 24, 1969. Neil Armstrong was the Commander, Edwin Aldrin, Lunar Module Pilot, and Michael Collins, Commander Module Pilot. I looked forward to this event for about a week, which is a long time when you are ten years old. I always loved gazing at the stars, but after that sleepless night our solar system, the galaxies, and what lies beyond became even more mysterious. Unfortunately, I never had the time to take Astronomy in college. My schedule never permitted it. But when my god-son began to question me about the stars in the sky, I explained them to him as best as I could. Hold on to your seat, we are going into outer space...
Mercury is a small planet, only slightly larger than our moon. The surface resembles that of our Moon as it is covered with craters and stony soil. There is no air or water on Mercury. It is the closest planet to the sun, making it very hot during the day. (Not on my list of vacation spots). Venus is the hottest planet in the Solar System. It reaches 480 degrees C. which is hot enough to make things glow a dull red color. Thick clouds of sulfuric acid cover Venus. These clouds never clear to let the sunshine through. These clouds help contribute to the heat on Venus as they trap in the Sun's heat. Heat can get through the clouds to the surface of the planet, but cannot get out again. The air on Venus is made of carbon dioxide gas. It is 60 times thicker than the air in Earth. Venus spins in the opposite direction to the other planets. It takes 243 Earth days to spin one time. This is longer than the time Venus takes to orbit the sun (225 Earth days), so a day on Venus is longer than a year. Here in Connecticut, Venus is the first and brightest light in the night sky and can be seen from April to October almost directly South in the evening sky. I saw her last night and she reminded me that, as weird or inconsistent as life can be for us humans, the planets are very dependable and orderly. It is often a comforting thought for me. Mars is sometimes called the "Red Planet" because it is made up of red rocks and dust. Even the sky is pink on Mars from the red dust. It is about half the size of Earth. Mars has ice caps at the North and South poles. Mars has 2 tiny moons named Deimos and Phobos. Phobos orbits Mars three times a day. Mars has the largest volcano in the Solar System. All of the volcanoes on Mars are dead and no longer erupt.
The Asteroid Belt is made of thousands of rocks going round the sun in space between Mars and Jupiter. Some asteroids are the size of pebbles; some as big as buildings; a few larger than cities; and my guess is that out there is one bigger than the State of Rhode Island. (Just a New England joke). Asteroids may be the remains of a planet that exploded millions of years ago.
Jupiter and Saturn are very much alike. Perhaps so much alike that
soon there will be a car manufacturer called Jupiter. They are
both made up of cold gases and liquids: Hydrogen, Helium, methane
ammonia and water. Jupiter is the giant of the Solar System, about
2.5 times more massive than all of the planets combined. It would
take 1400 Earths to fill a
Uranus is a giant gas planet. It appears greenish-blue because of the chemical composition. It is circled by nine rings made of ice and rocks. These rings were only discovered by scientists in 1977. Uranus spins around in a different way than all the other planets. It seems to be lying down, as opposed to the others which appear to stand up. Due to this lying down position, Uranus has very strange days. Days and nights are 42 Earth years long on some parts of Uranus. Neptune is so far from the sun that is takes 165 Earth years to orbit the sun. Pluto, the last planet in our Solar System takes 247 Earth years to orbit around the Sun. Until 1915, Neptune was thought to be the last planet of the Solar System. An astronomer, Percival Lowell, worked out that there should be another planet beyond Neptune. He named it planet X and searched for many years but did not find it. In 1930, another astronomer, Clyde Tombaugh, was taking photographs of stars. He noticed a stray "star" in a picture which he could not identify. It was realized that he had photographed the mysterious Planet X. It was later named Pluto. Stars are giant balls of hot fiery gases, like our Sun. They appear smaller than the Sun and planets because they are much farther away. Stars are not all the same; they come in a variety of colors, shapes, sizes, temperatures, and brightness. The Sun is a common type of star. All stars form in huge clouds of gas and dust. After time these gases combine together and begin to heat up as a clump. Eventually the dust and gases get so hot that they start to glow and "shine." It is then that this combination has become a star. Stars last for thousands of millions of years, but they do not stay the same forever. Changes occur as they age. Stars are so far away that we measure the distance between them and between the earth in "light years". (Discussed earlier). While the nearest star is 4.5 light years away, many stars are hundreds of light years away. Our Sun will spend most of its life as a yellow star, about 10,000 million years. Eventually, it will expand and change from yellow to red and become a Red Giant Star. Red Giants are a hundred times larger than the Sun, but cooler and brighter. This type of star is at the end of its life. After a star like our Sun turns into a Red Giant, it slowly cools down and shrinks. The outer layers will separate and go off into space. This new "thing" is called a White Dwarf Star.
Stars larger than the Sun also become Red Giants. A Supernova is a
massive Red Giant star that has expanded and exploded. The explosion
is called a Supernova. Supernovas occur with stars that have masses
greater than five times that of our Sun. For several months Supernovas
may shine 10 billion times brighter than a normal star.
A Supernova leaves behind a Black Hole which acts like a gigantic
cosmic vacuum cleaner that sucks in anything that goes near it,
Our galaxy measures about 80,000 light years across. Stars are not really scattered randomly about the Universe, they are gathered in enormous groups each containing hundreds of millions of stars. These groups we call galaxies. Our Sun is a star in the galaxy called the Milky Way--which is shaped like a spiral. (I prefer the dark chocolate Milky Way bar, if you can find them). More stars are located in the middle of the galaxy than around the outside. As you haved guessed by now, galaxies do not just hang out in space, they slowly spin. The complete spin is called a galactic year. The Milky Way takes 225 Earth years to spin one time. There are millions of galaxies in the Universe. Some look similar to ours, others are different in shape.
Comets are made up of gases, ice and dust. Only about 20
come close to the Earth each year, but only a few are bright
and large enough to be seen without a telescope. About every
ten years we may be lucky enough to see a large comet. These
comets can be viewed from Earth for weeks or months.
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