History Channel
Season. 01 Episode. 10
http://www.history.com/shows/the-universe
http://en.wikipedia.org/wiki/The_Universe_%28TV_series%29
http://www.youtube.com/watch?v=_OtkgXnMErc
EXCERPTS:
PILLARS OF CREATION
7000 LIGHT YEARS FROM EARTH
EAGLE NEBULA
To form a star like our Sun
which is a million miles across,
it takes a clump of gas and dust
100 times the size of our Solar System.
These clouds start off their lives bitterly cold,
with temperatures hundreds of degrees below zero Fahrenheit.
But as gravity fragments and compresses them,
the heat begins to soar.
[is this explanation equivalent to religious sayings (imam Ali) that Universe is made up of water. Clouds Cold - doesn't resemble to water?!]
"Gravity want to CRUSH the star down to the middle.
For stars, nuclear fusion provides the rope in the form of pressure."
(nuclear fusion of star try to resist this gravity to not be crushed)
"Red Dwarfs are very common in the universe"
"The more massive stars live much shorter lives than the less massive stars."
"it won't be able to fuse that helium into heavier elements,
like carbon and oxygen,
until the core gets sufficiently hot.
And that's because it's harder to get the helium nuclei close enough together
for the strong nuclear force to take over,
grab them, and cause them to fuse together.
"When it reaches 180 million degrees, it can start fusing helium into carbon,
in a desperate gamble to survive."
"The star which took 10 billion years to burn through its hydrogen,
now powers through its supply of helium in a mrere 100 years.
"it runs out of H, starts fusing He,
runs out of He, attempts to fuse C and will fail."
As the star the size of our Sun dies,
it eject its outer layers.
(due to loose gravitational force, and shapes like Planetary Nebula)
"The white dwarf has about 300,000 times the mass of the Earth,
compressed into a volume the size of the Earth.
If you had just a teaspoon full of material, it would weigh several tons."
"The White Dwarf is the final stage in the life of a Sun-like star.
But it's not quite dead yet."
White dwarfs are retired stars, lives billions of years on the energy which they saved in their youth.
Thermonuclear runaway
Type 1 super nova
supernova happens twice in each galaxy per century.
"It goes through its normal life fusing H into He,
then Hel int C and O, then O into Ne and Mg
and then Si and Sulpher.
and then Iron (Fe).
Supernovas are in fact source of heavy elements.
"All the iron you see everywhere came from exploding stars.
And in fact all the elements heavier than iron directly or indirectly were made by
exploding stars."
"If you could trace your ancestry back to its earliest reaches,
you would find an exploding star in your family tree."
"The elements in your body - not generically but specifically -
heavier than H and He,
came from long-dead stars.
The Ca in you bones the O that you breathe,
the Fe in your bloodcells, the C in most your cells...
All those things were created in stars through nuclear reactions.
and then ejected by supernovae."
NEUTRON STAR
"Compared to normal stars, neutron stars are cosmic pebbles.
They can be as small as 10 miles acros.
... extremely dense object.
one teaspoon full of neutron star material would weigh a billion tons."
"Black holes are basically gravity's victory over mass."
"In the fall of 2006,
astronomers observed the largest stellar explosion
ever witnessed by Man.
240 million light years away from Earh,
a massive star blew itself apart.
A normal supernova comes from the explosion of a star
10 times more massive than our Sun.
Incredibly, supernova 2006GY, as astronomers have dubbed it,
seems to have signaled the death of a star
150 or even 200 items more massive."
Fortunately, the chances of this (colliding stars) happening are slim,
because the Sun is in a very uncrowded part of the Milky Way.
"Blackholes, neutron stars and white dwarfs,
all represent the end of remarkable stellar lives."
BROWN DWARF
not quite planets, not quite stars.
"brown dwarfs are basically failed stars."
PROTOSTAR
MAIN SEQUENCE
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