There's nothing in physics that ever said that it was impossible to break the sound barrier, but it's pretty fundamental to our understanding of the universe that you can't break the light barrier. I'm not saying that it's definitely impossible, but it certainly isn't a technological inevitability.

This is what I've always thought. I mean, in order for any civilization to travel conveniently between stars, they'd have to learn to break one of the most fundamental laws in physics and travel faster than light. It doesn't seem like something that we can just handwave and say "They'd have had time. They'd have…