He's synonymous with genius, but Albert Einstein is also best known for what is easily the world's most famous equation, E=mc². But did you know that it's actually a shortened version of a longer equation?

E=mc² only describes objects that have mass but *aren't* moving. The full equation, used for bodies in motion, is E²=(mc²)²+(pc)² where that extra 'p' represents the momentum of an object. Besides being important for calculations on everything from celestial mechanics to rocketry, it's also important proof why anything with mass can't travel at the speed of light—no matter what Captain Kirk's orders are. [YouTube]