[cameltoe]

by the theory of relativity and other shit we learned about in precal, to achieve time travel , youd have to go the speed of light, and your mass would increase exponetaly til it eventually becomes infinate and you become the universe kinda. so either they find some other way in the future and came here... the only other theory to travel thru time is going thru a black hole, but the gravity in those things is so great it bends light rays and whatever goes it never comes out.