[timeagain]

This is a central theme in Vernor Vinge’s Deepness books. Space travel is slow (100s-1000s of years), so travellers are forced to calculate the likelihood that their destination will have experienced societal collapse by the time they arrive. The idea of a perpetually-sustained civilization is a failed dream. Technology helps societies bet larger and last longer, but also more dependent on the technology to sustain their growth.

[cubefox]

But the population size theory says this is increasingly unlikely the larger the population gets. Even Gran Canaria was large enough to avoid the loss of crops for a thousand years, unlike the populations on the smaller islands.

[heavenlyblue]

In real life you could take a ship between two different distant lands and when you arrive it is ravaged by war started a couple of days ago