We are very small...

[GohanX]

http://www.youtube.com/watch?v=7NYRVsKAkFM

Yea I knew the sun wasn't as big as other stars out there but this blew me away:eek:

[Volk]

I knew that there was bigger suns out there..... But good grief! The biggest sun on there would be called a "Red Giant". I knew they were big but....GOOD GRIEF!!!! Like you said. We are small.

[Monster Hunter]

I already knew that but think about this.

Once the core of the sun runs out of hydrogen to fust nuclear reactions switch off. With no energy production in the core, the pressure drops and no longer counteracts gravity.
Consequently, the core collapses, heating up as it converts potential energy to kinetic energy. It drags some of the un-fused hydrogen from outside the core along with it - which heats up too and starts to fuse. This creates enough energy to cause the outer layers of the sun to expand into a red giant.
A red giant is large and significantly brighter than the sun currently is - but cooler (3000K)
When this will happen is ~5-7billion years from now. Whether the Earth will be engulfed is not settled - but the conservative estimates show that the surface temperature of the Earth would be ~1400 Kelvin - hot enough to evaporate all the atmosphere and melt the surface rocks!

Eventually the the core collapses enough to fuse helium into carbon, which marks the end of the red giant phase.
This phase ends when the Helium runs out and the process of becoming a red giant happens again.

This time the sun will get bigger and brighter than the first red giant phase. Because of its size and because it is a little unstable it starts to lose material out into space. Surface gravity if low, so escape velocity is low, and instabilities cause pulsations which push material away from the star.
As the hot gas flows away from the star is cools and produces dust (a bit like soot forming about the hot gas from a fire).

Eventually there isn;t much material left around the core of the star and it cannot support itself, so it collapses and heats up to become a white dwarf. Now you have a very hot, very small star in the center of a cloud of gas and dust that was thron off into space. The photons from the star illuminate the gas (and dust) and you get a planetary nebula. The nebula gas and dust continues to drift of into space and the white dwarf slowling cools. Edit: Once the collapsing of this star happens then it gives off more energy than the stars gravity can handle. In turn it implodes creating enough energy to rip the fabric of space causing a black hole. End of edit 12/24/08

It terms of how long all this takes:
it will be ~6 billion years until the sun becomes a red giant
1st redgiant phase lasts ~100 million years
time before another red giant phase ~ a few million years
2nd red giant phase ~ a few hundred thousand years
post red giant/planetary nebula phase ~ 10,000 years
cooling time of the white dwarf ~ billions of years (maybe a trillion years)

Stars like the sun and up to 8 solar masses follow a similar path, but the timescales get shorter as the mass goes up.
Above about 8 solar masses stars do more things and eventually supernova, and end in either neutron stars or black holes. Initial mass of the star needs to be greater than ~15 solar masses to get a black hole (a really big black hole...) yes I am kinda a nerd....:( I think Space has to be one of the craziest things ever. look up anti-matter string theory and bubble theory. ( I was bored one day and in suddenly bubble theory came up in my mind which I have never heard of until a week later a science show said the same thing I came up with!!!! I'm not lying!!! how crazy I'm just 12) Space is my future.

[GohanX]

You just summed up my what my astronomy teacher taught us last year about stars lol

As a matter of fact the sun will expand beyond Mars and will totally engulf the Earth. Cooking everything on it to a crisp:P.

Stars our size, like you said, turn into white dwarfs. Which actually is a big diamond like sphere because it is made up of carbon.

Nerdy? Yes. But i'll take my "A" and be a nerd then take an "F" and be cool any day:D

[Jack]

^^Wikipedia ***** =P

[Volk]

the sun will expand beyond Mars and will totally engulf the Earth.

Marshmellows anyone?:D

[Monster Hunter]

^^ actually its called paying attention in class and not being an idiot.:mad:

[GohanX]

He was just kidding man. Don't lose your cool over it:D

[Monster Hunter]

opps sorry i take things to personal some times ;o

[Papelbon]

Wow! We're, well TINY! Thanks for sharing this info man! :o

[Deadpool]

Well I had a pretty good idea that we were a very tiny speck out there. Most stars are 20 times our size.
And I don't think the Sun going into all those phases is a concern for us, humans would be extinct by then.

[Monster Hunter]

^ur right.

[HRBEK]

Ah Antares... What a fine entity, haha. But think, somewhere out there, there's gonna be a sun 20 times as big as Antares, lol. Space (Astronomy) is an interesting thing. Don't know why some people aren't interested in it.

Thanks,
HRBEK.

[dcsboy12]

Me too. I think there will be lots more suns wayyy bigger then the one we know.:(