this is just for fun speculation. But lets try and keep realistic without bending laws of physics. No mass migration to other star systems.
People seem to think that humanity in the solar system is doomed. The sun will swell, perhaps engulf the earth, and shrivel to a white dwarf and that will be an end to it.
But would it.
Why would humanity not be capable of surviving this.
How long can we keep Earth habitable. As the sun heats up, isnt it reasonable to think we would have the ability to control the suns energy that reaches out atmosphere? perhaps a vast roller blind between us and the sun? If i remember right, we have max a billion yrs before we have either protected the planet, or it will be baked.
so then perhaps we can get a few more billion yrs untill the sun enters its red giant stage.
I seem to recall hearing that the earth may migrate its orbit towards the outer sytem, but it is not certain if it would be engulfed or not.
Its migration out could be amplified artificially by hurling asteroids past it giving it an extra tug. Maybe the earth as a gravity chunk of rock could be saved? it is unlikely that a nice green planet with breathable air would survive, but hey, domes are cool right?
If the Earth cannot be saved, i guess you would want to find the largest chuck of rock you could in the outter system to give as close to 1g as possible. it would be a good idea to have atmospheric pressure too id suppose.
As the sun blows off its shell, we are left with a weak white dwarf, but there will still be plenty of resources around... assuming that we can get the hang of fusion power generation, we can heat and light out cosy domes.
and then theres andromeda. We will be in the mix, but we probably wouldnt really notice much in out quet little system.
i dont really see a good reason why our ancestors wont still be around in 6 billion yrs.
but maybe im missing something...quite likely