+18 The speed of light (299 792 458 m/s in vacuum) is the fastest we know. It is not possible to smoothly accelerate a material object to, or beyond, the speed of light.
+633 Only things without mass can reach the speed of light. One or both of Einstein's Theories of Relativity describes why nothing can go faster than the speed of light. I think of it as a time paradox - once you reach the speed of light, you stop feeling time.
