If you want to travel back and forth between inhabitable stars, forget rockets. They're just never going to get you moving fast enough. I'm basically talking a

If you want to travel back and forth between inhabitable stars, forget rockets. They're just never going to get you moving fast enough. I'm basically talking about a propulsion system that we haven't imagined yet. Because nothing we've (realistically) imagined would make an interstellar civilization possible. I didn't say they wouldn't exchange beings or materials at all. I'm just saying that individuals will not be hopping in their space cars and cruising off to the crab nebula for the weekend.