Yuri Milner wants to explore Alpha Centauri with a tiny spaceship propelled by the biggest and most powerful laser cannon ever built. That may be a lot harder than it sounds.

If aliens want to go really, really fast, there's a small chance we could catch them in the act.

Can we turn black holes into a way to explore space at relativistic speeds? A pair of physicists thinks it may be plausible if we have enough powerful lasers...

Mathematician with an interest in general relativity, Burkhard Heim, had an idea for a war drive powered not by nuclear fusion or the decay of exotic matter, but by magnets.