Question: Would it be possible to survive the suns death, or at least lengthen the time we have until it finally does die?

Kristian Harder answered on 14 Nov 2013:

Well, this is about 5 billion years into the future. The first big question is whether mankind (or whatever it evolves into over that timescale, given that it took only a few billion years to develop simple bacteria into human beings 🙂 ) will still exist, given how badly we have treated ourselves and our planet so far.
But let’s assume there is still anyone who is around to worry about having to survive the death of the sun, here’s what I am thinking:
There is no way to survive on earth in its current location, because the sun will turn into a red giant towards the end of its lifetime, swallowing Earth (or maybe just getting so close to it that it will essentially burn up). So we’d either need to get Earth into an orbit further out (which would be a gigantic task, but is not entirely impossible), or we’d have to move elsewhere, either on a planet or moon in the outer region of the solar system, or even into a different solar system altogether.
Extending the life of the sun seems pretty much impossible. The problem is that it is eventually going to run out of hydrogen to burn, and feeding it an additional bottle or two is not going to be enough to make any difference. Even if we threw all planets into the sun (Jupiter, above all, which contains quite a bit of hydrogen), it would hardly make a difference given how much smaller the planets are compared to the sun itself. You’d essentially have to feed it a big chunk of a different star to really extend its lifetime – but how would we get that much material here?
So, extending the lifetime of the sun doesn’t seem to work. We’d have to learn to live without it. Living in the darkness without a sun might work thanks to our technology (you’d probably have to throw away all remaining solar cells you might still have, though 🙂 ), but, as I said, it would have to be elsewhere.
We could send a large number of people onto big starships in search of new places to live, or we could even resolve to live on starships forever. Imagine how sad a moment it would be for mankind to leave Earth behind… But who knows, maybe, in a few billion years, mankind will be so used to space travel, maybe we will have colonized other planets anyway, and most people might not care about as much about Earth as I do about the town I was born in. In other words, it would probably take a long while to notice if it suddenly disappeared from the universe. 😉