death of the sun

I can't post comments lately, so am responding to Quintins question here.

The sun will run out of hyrdogen in 4-5 billion years. Excepting a early death by some alien bombing it or something Probably longer than you'll live. After that, it will fuse the resulting helium, causing it to expand. At its widest, it will engulf Earth and probably mars as well. after all the helium is burned it will cool and shrink. but earth will be a floating pile of ashes then. the expanding shrinking will take 5-8 billion years