> As an SF writer, it's pretty interesting, though, to think of the weird shapes a society would take when your astronauts are outliving entire civilizations.
I guess this all depends on how you define simultaneity. Say I got on a relativistic rocket traveling near c and colonized Planet X in 10 years ship time and say 20,000 years Earth time. I put up my TV antenna as soon as I land, and I'd still be receiving Earth transmissions from approximately 10 years after I left, no? So even though civilization is long gone from Earth's point of view, from my point of view, I can keep up with the latest news as if I were still living there. So from my point of view I did not outlive anything.
If I were to go back, yes, everything would be gone.
I guess this all depends on how you define simultaneity. Say I got on a relativistic rocket traveling near c and colonized Planet X in 10 years ship time and say 20,000 years Earth time. I put up my TV antenna as soon as I land, and I'd still be receiving Earth transmissions from approximately 10 years after I left, no? So even though civilization is long gone from Earth's point of view, from my point of view, I can keep up with the latest news as if I were still living there. So from my point of view I did not outlive anything.
If I were to go back, yes, everything would be gone.