> the distance between solar systems is so incredibly massive, and the impossibility of FTL so real Those things, and the likely temporal separation of civiliz

> the distance between solar systems is so incredibly massive, and the impossibility of FTL so real Those things, and the likely temporal separation of civilizations - where they miss because one peaked one million years before its nearby neighbours. E.g. Proxima Centauri, our nearest star, which per Wikipedia, is 200 million years older than the sun, so a civilization there which matured at the same speed as ours, would likely be long gone.