ASTRONOMY, CHEMISTRY, PHYSICS
Origin of universe
The universe was created 12 billion years ago in the big bang (Sagan)
(15 billion years ago according to my other documentaries). Before
the big bang, the universe was smaller than the size of a nucleus.
In the 10 to the –43 second to 1st second, only protons and neutrons were
formed. From the 1st second to 1,000 second, hydrogen and helium
(100 seconds) were formed. 10 –35 sec: electro-weak and strong were
together. Only 2 forces. Gravity and this electro-weak-strong
force. 1/10th billion of a sec: Electromagnetic and weak bounded
up together. Electro-weak forces. Only 3 forces.
It’s not known what happened earlier than 10 to –43 second. The
microwave radiation from the big bang is still detectable today, such as
in the static that comes from a TV.
The fate of the universe
We know that the universe is expanding – Hubble was the first
to discover this by observing a red shift in galaxies. Light travels
in all directions like the ripples created from a rock that is thrown into
a pond. But if the object that is emitting the light is moving, the
light in front of the object will get squashed, making the light waves
shorter, resulting in a red shift. If the galaxies were contracting,
then a blue shift would have been observed, but blue shift has not been
observed.
If there is not enough matter in the universe, the universe will
continue to expand forever, and eventually all the stars will burn out,
and the universe will become dark. If there is enough matter in the
universe, gravity will pull on all the matter in the universe and collapse
into 1 point. At this point, another big bang could occur.
It is possible we exist in an universe with an infinite cycle of big bangs
and contractions.
We have been trying to measure the universe’s weight, but if
90% of the universe is dark matter, which we can’t see, we will never be
able to weigh the universe with accuracy.
Interestingly, Einstein thought the universe was stable.
When his initial calculations showed that the universe was changing, he
thought he had made a mistake and added a cosmological constant to stabilize
the universe.
The contents of the universe
The universe is mostly empty space. 99.9% of matter is hydrogen
and helium. There are a 100 billion galaxies in the universe, with
about 50 to 100 billion stars in each galaxy. At light speed, it
would take 2 millions years to reach the nearest galaxy Andromeda.
Our Milky Way galaxy is 100,000 light years long.
Stars
Stars are formed from swirling dust and gas. Some planets
are so big, they can become a star. Stars convert hydrogen into helium
constantly, and each time this occurs, the star releases light.
The eventual fate of a star depends on its mass. All stars
will become a red giant. They will increase in size. When white
dwarfs such as our sun become a red giant, it will become so big that it
will engulf the Earth and temporarily turn helium into carbon. Then
it will burn out.
Stars that are 1.5 times the size of our sun will become a supernova
– an explosion that is so bright that it is brighter than all of the stars
put together. A supernova was observed in China in 1054 AD – the
explosion, which lasted 22 months, lit the sky so bright that it was possible
to write at night with its light. This explosion created the Crab
Nebula.
When a supernova occurs, 3 things could happen: 1) It explodes, 2)
becomes a neutron star, or 3) becomes a black hole.
Explosion
The star’s contents will be sent back into space where it can make
up other stars.
Neutron star
A neutron star has the diameter of about 20 km. Neutron
stars that flick on and off are called pulsars.
Black hole
The gravity of the star can pull the surrounding contents into an infitesimally
tiny point that is so powerful that it even sucks in light, also known
as a black hole. It is not known what is inside a black hole – perhaps
it is a gateway to another part of the universe, or maybe even another
universe altogether.
Supernova
Only within supernovas can fusion of heavy elements occur, where
energy is absorbed.
Sun
Our sun was formed 4.5 billion years ago. It will die out
in 5 billion years. The sun is 150 million km away from Earth.
Earth
Earth was created when it was collided by a similar size planet.
The explosion was so great, both planets melted into one new planet.
Mars
Had some river beds, which probably means it had water. It also
has some extinct volcanoes. In 1994, a meteorite from Mars with some
bacteria on it hit Earth. For the first time, we found out that there
was life on Mars at one point. Sagan said Mars is a warning to us
for what happens to a planet without an ozone.
Venus
The most volcanically active planet in the solar system.
Jupiter
Jupiter is the vacuum cleaner for the solar systems – it draws
all comets to it.
Life
From what we have observed, wherever there is life, there is
always water. So if a planet is too close to a star, water will never
form there because it’s too hot. But even if a planet is far from
a star, it could still harbor life. For example, we know that there
is ice on the farther planets. Gravity between planets could create
volcanic activity. This heat would melt ice and create water, which
could bring rise to life. We know this is possible because of life
on Earth that arose next to geothermal vents deep under the sea.
Life in the solar system
In 1994, we discovered that there was life on Mars from a meteorite
that hit Earth. But other than that, the only life we know of is
on Earth.
Life on Earth
Life on Earth arose in a primordial goo, where molecules began creating
crude copies of themselves.
Dinosaurs died 65 million years ago when a meteorite hit Mexico.
Elements on Earth
There are 92 naturally occurring elements on Earth. Everything
above 92, we created artificially are all unstable. The elements
on the left side of the periodic table are metals, while the ones on the
right are gases.
Isotopes
An isotope has a differing # of neutrons of the same element.
An unstable isotope, or radioactive isotope, decays into smaller elements
at the end of each half-life in attempt to become stable. It continues
to decay until it is stable. Each time a radioactive isotope decays,
it release energy, or radiation in the form of alpha, beta, or gamma rays.
This radiation originates from the weak forces that were holding the isotope
together.
By measuring the mass of an isotope, we can calculate its age.
This is how we figured out how old things are on the Earth. No object
found on Earth has been measure older than 4.5 billion years.
Ions
An ion is an atom that has gained or lost a proton or electron.
All ions have either a positive or negative charge (http://www.encyclopedia.com/doc/1E1-ion.html).
Compounds
To create compounds for 2 elements, just switch the subscript
# between the 2 elements, and then I’ll know how many atoms are needed
to balance the equation.
4 types of matter
solid
liquid
gas
plasma: ionized gas
4 fundamental forces
gravity
strong force: holds nucleons together, which is built by particles
smaller than electrons and nucleons
weak force: weaker than strong force. Holds neutrons and protons
together?
Electromagnetic: holds electrons and protons together
atomic particles
Neutrons: made of the udd quarks (one up quark, 2 down quarks)
Protons: uud
Fusion
Energy (photons) is released in fusion when a neutron is pushed
out of the nucleus when forming the new element. This occurs in the
sun all the time when it is converting H into He.
Radiation
There are many types of radiation, but the ones that are discussed
in my chemistry book are alpha, beta, and gamma rays. Rays are actually
particles (http://education.jlab.org/qa/radbegin_04.html or Jefferson lab)):
Alpha rays:
Alpha rays are composed of 2 protons and 2 neutrons (Jefferson lab).
They are looking for 2 electrons, and once they do, they stop and become
helium. They can be blocked by paper. Alpha rays are big, so
the damage it does to the human body is the least of the 3 rays.
It cannot reach living tissue from the outside (Jefferson lab). However,
once inside the human body, it does the most damage because they cannot
pass through the body as easily. A body can survive diffused damage
throughout the body, but not focused damage.
Beta rays:
Smaller than alpha rays, bigger than gamma rays. Beta particles
are high-energy electrons (an electron or positron) (wikipedia).
Can be blocked by aluminum plate (wikipedia).
Gamma rays:
Gamma rays are photons (wikipedia). Photons have zero rest mass
and no electric charge (wikipedia). Photons are produced when an
atom goes to a lower energy level (i.e. radioactive decay) (wikipedia).
When a particle is annihilated by its anti-particle, 2 photons must be
created (wikipedia). Smaller than beta rays, a lot of shielding is
required to block gamma rays, such as lead or concrete (wikipedia).
Gamma rays do the most damage in a radioactive explosion because it can
pass through many objects due to its small size. It does the least
amount of damage inside the body.
To illustrate how little damage gamma rays do inside the damage, some
radioactive isotopes that release gamma particles are used in destroying
cancer cells. These isotopes have a half-life of 6 hours.
Atomic bomb
One a-bomb was made of uranium, while the other was made from plutonium.
A neutron was shot into the nucleus, causing it to decay (fission), starting
a chain reaction.
A hydrogen bomb, more powerful than an a-bomb, involves fusion of hydrogen
atoms. It releases 7% of its energy.
Anti-matter
In recent years, we have been able to make anti-matter – specifically,
anti-hydrogen. However, they only survive 10s of seconds. Furthermore,
it costs $20 million to create a pictogram of antimatter. The clash
of matter and anti-matter releases 100% of its energy, but because it is
too costly to create this clash, it is not worth the money (all wikipedia).