Okay, so I'm no physicist, but I just had a random thought. So they say that traveling at the speed of light is impossible because the mass of the engine would have to be constructed infinitely big. But what if the propulsion didn't come from the spacecraft? I was wondering what you guys and gals thought about a device that would pull the spacecraft to the speed of light, instead of push. Think of a slingshot. It was just a random thought. It may be totally idiotic. I don't know, I just love physics. :) What do yall think?