Ludicrous Speed!

"Is there any definitive proof that we can't travel faster than the speed of light?"

None whatsoever and Einstein never said it was an unbreakable barrier. Light is just a particle, and we can vary it's speed with gravitational forces. I've often spent my life wondering why people read more into what Einstein said than he did. The extreme layman's terms is this: he theorizes that light appears as a constant TO YOU no matter what speed you're travelling. You can easily be travelling, relativistically speaking, faster than the speed of light from another observer's standpoint but you can never travel faster than light from your own perception, because you'd necessarily be disrupting it at your base speed always. Remember we do not see light, we see deviations in it and reflections of it.

Have you ever been in a car travelling 60 MPH and thrown a ball to another person in the front seat? To you, the ball's maybe going 5 MPH; it is, in fact, going the "speed of thrown ball". However, the "speed of thrown ball" to you would be oh... 65 MPH to someone standing on the roadside observing only your ball.