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View Full Version : How long, how come!!!!


Nec
May31-04, 10:57 PM
Can anyone tell me when the stars will die out ?
What makes it ?

Thanks

marcus
Jun1-04, 12:13 AM
Can anyone tell me when the stars will die out ?
What makes it ?

Thanks


Nec, there still are stars being formed.
We can see them condensing in clouds of gas
and beginning to glow

Nature has not yet finished making stars

it is still early to be talking about when will they all be dead.


But it is still possible to try to estimate when most will be dead.
the difficulty in saying is that the large hot bright stars burn out quickly
and the medium size stars like the Sun last a medium time like 10 billion years
and the little stars a quarter or a tenth the mass of the sun are dim and burn very slowly and last a very long time

So even 50 billion years from now there will probably be some stars

many will have burned out and grown cold
but there will still be dim slow-burning stars

perhaps you would like to prepare for the long wintertime.
If you want, I will sell you one of my stars, the small kind that burn for a very long time

Phobos
Jun1-04, 10:08 AM
Welcome to Physics Forums, Nec.
Stars form from clouds of mostly hydrogen. That hydrogen is the fuel for the fusion reaction that makes stars shine. Each star has a finite amount of fuel, so eventually, they run out. Like marcus said, a star like our sun lasts about 10 billion years before burning out. It's end stage will be a small "white dwarf star" that will simply cool off over billions of years into a ball of ash.
Larger stars burn brighter and have shorter lives. Smaller stars burn cooler and live longer.
Even 100 billion years from now, there will still be stars, but there will only be small, cool stars and the cooling remains of former bright stars. Eventually, long after that, even those stars will die out.
But no need to be gloomy...we live in a wonderfully warm/bright time now.

marcus
Jun1-04, 10:57 AM
But no need to be gloomy...we live in a wonderfully warm/bright time now.

yeah, no need to be gloomy, this is a very nice time.
Besides even if all you have left is a dim small star (the kind that burns very slow) all you need to do is sit closer to it!

If you are still worried, I will even give you one of my long-lasting stars for free. there are plenty