Answer:
um... the lifespan of the sun is 12 billion years, we are about half way to the 12 billion mark. (a little less). I think about 4.2 billion years old. The sun will engulf mercury and venus in the last 2 billion years of its life span, then it will either burn out or explode. If it has a higher mass, then it would explode then turn into a black hole! whopee...