When?

When will the Sun burned out?

About another 5.4 billion years

Our sun is a star and is not actually alive, thought it is very active. It is a star, and like many stars that are about the same size (mass), it follows a pattern of development on the main sequence. Our sun will burn (fuse elements) for a total of about 10 billion years. Since our solar system is about 4.6 billion years old, therefore our sun has another 5.4 billion years to go. However you must understand that the sun will change as it ages as it begins to fuse heavier elements. It is presently getting hotter and hotter and in about another billion years the earth will not be a very pleasant place to live. Towards the end of its life it will puff up to become a red giant and its outer surface will be around where the earth orbits. In the end it will blow off its outer layers in a planetary nebular and what will be left is a small hot core called a white dwarf which will slowly cool and fade.