When the sun goes out....

[frosch45]

I can't remember the exact figure, I think that it was 5 million years, but isn't that when the sun goes out? Well, I obvously don't know much about astronomy or anything as you can tell by my technical terming but I just thought of something.

 

Two things

 

1) Isn't there a time delay for the light/heat radiation from the sun to get to earth? 7 seconds is it?

 

2) When the sun "goes out" or colapses or crunches or what ever it will do, by this I mean when it ceases to produce the heat and light necessary for life on earth to continue, how long will it take before our earth completely cools to 0 Kelvin when taking into consideration the specific heat of all of the earth's particles.

 

Obviously, there could be so many problems with that question in the first place that it may be impossible to answer, I just wanted thoughts if you could give them.

[Kyrisch]

A star doesn't die quietly. The sun is projected to expand until its radius more than subsumes the Earth's orbit. Neglecting this, it would take approximately 8 minutes for the light and heat to span the approximately 8 light minutes from here to the Sun and 8 minutes for the theoretical gravitons to cease interaction as well.

[Cap'n Refsmmat]

It's five billion years, actually. The answers to your questions:

1. About eight minutes.
   
2. It is pretty much impossible for anything to cool to 0 Kelvin. Take a look at the Wikipedia article on it.
   

[frosch45]

I did understand that it was nearly impossible to cool anything near absolute 0. I guess that I should have specified that I meant that the earth would cool to a degree of constant, well, for lack of a better word, coldness because the sun would no longer be heating it. I guess that there is heat coming from other sources (maybe other stars) but this has to be a very small amount right?

[Cap'n Refsmmat]

The Earth is capable of producing its own heat -- the immense pressure at the center of the Earth is enough to liquefy rock and keep things warm. You'd have to wait for the Earth to "go out."

[iNow]

It's sort an irrelevant question since when the sun goes red giant it will engulf the earth. Frosch, here's a decent link to assist with such questions, with several good links to other great info:

 

http://curious.astro.cornell.edu/question.php?number=48

[frosch45]

Thanks

 

I really have apsolutely no expierence in this field, that article is interesting.

[Mr Skeptic]

The Earth is capable of producing its own heat -- the immense pressure at the center of the Earth is enough to liquefy rock and keep things warm. You'd have to wait for the Earth to "go out."

 

It's actually nuclear powered. Radioactive isotopes in the earth's core decay, releasing heat. The pressure actually tends to solidify, not liquefy, and is why the earth's core is solid.

 

So digging a bit into the earth, enough for the earth above you to act as a blanket, you can get as warm as you like, even if the sun dies and the surface is freezing cold. Oh, and the surface will be warmer than the temperature of the cosmic background radiation, which I believe was about 2.7 Kelvin, or thereabouts.

[Arch2008]

This is a more accurate discussion of what will happen to the Sun.

http://imagine.gsfc.nasa.gov/docs/science/know_l1/dwarfs.html

 

As a white dwarf, the Sun will no longer fuse elements, however the heat that was in the Sun’s core when it collapsed will be trapped by the now super dense Sun. This heat will take something like a trillion trillion years to dissipate by convection. So an enterprising race will still have a source of heat and light, although a very small source, from the Sun for a very long time.

[Vindhya]

Actualy I remember reading that after sun becomes a red gaint first mercury will go inside the sun then venus. After that earth will be the first planet, the heat from the sun destroys everything on earth. Then eventualy all planets will go, then after some million years our sun will become a supernova, then a dwarf star and afert some years it will disappear. As I know this is the end of our sun.

It takes 8minutes and 10seconds for the linght to reach earth form the sun.

Edited July 11, 2008 by swansont
multiple post merged; duplicate deleted

[Arch2008]

Not every star becomes a supernova. The determining factor in this event is the star’s mass. We are able to calculate the Sun’s mass. We know the Earth’s mass from its force of gravity and we know how the Earth moves around the Sun. We use this to calculate the Sun’s mass (about 300000 times the Earth’s mass), which is not enough for the Sun to become a supernova. Once the Sun becomes a white dwarf, it may not “fade away” for 10^100 years.