|MadSci Network: Astronomy|
Our sun will die in about five billion years; at least that is what we think based on our current theories. We presently think that stars fuse hydrogen into helium in their cores. This process releases the energy that ultimately is emitted as electromagnetic radiation from the surface of the star. The lifetime of a star is then determined by the amount of hydrogen that it has when born. Thus the lifetime of a star is determined by its mass. A star with the mass of our sun is thought to live a total of ten billion years. Other evidence persuades us that the sun has been shining for five billion years and will begin its death process in another five billion years. This is discussed in much more detail on many web sites which can be found with any good search engine like metacrawler.com.
Try the links in the MadSci Library for more information on Astronomy.