Our sun’s death is a long way off — about 4.5 billion years, give or take — but someday it’s going to happen, and what then for our solar system?
The trouble begins before the death proper: The first thing we have to contend with is the elderly sun itself. As the fusion of hydrogen continues inside the sun, the result of that reaction — helium — builds up in the core.
With all the waste product hanging around, it gets harder for the sun to do its fusion dance. But the inward crushing weight of the sun’s atmosphere doesn’t change, so to maintain balance the sun has to increase the temperature of its fusion reactions, leading ironically to a hotter core.