Actually there's an engine, which is said to create warp-like bubble. Plus, we know nothing about the physics so many things to us seem impossible. It is arrogant to say that FTL is impossible, since we haven't proven that and our understandment of physics (we haven't confirmed Strings Theory yet) can be... well, not wrong, but errorously understood.
We should always take into consideration a little fact that some points of our basis may be wrong. Like it was a common knowledge that it is impossible for many tonnes plane to fly.
