1. The problem statement, all variables and given/known data In terms of the energy involved (using formulas provided), explain why accelerating a spacecraft to the speed of light is impossible. 2. Relevant equations time, mass and length dilation formulas, and a few astrophysics formulas, E = Ek + mc2, projectile motion formulas 3. The attempt at a solution I have solve this mathematically by using the mass dilation formula to prove that mass would be infinite and then subbed that value into E = Ek + mc2 to prove that energy would be infinite. I don't think this is a good way to explain/solve this question. Can anyone else please explain this using the formulas provided?