Why exactly can nothing go faster than the speed of light?
"Imagine you're driving in your car when something terrible happens: the brakes fail. By a bizarre coincidence, at the exact same moment your throttle and gearshift lever both get stuck. You can neither speed up nor slow down. The only thing that works is the steering wheel. You can turn, changing your direction, but you can't change your speed at all.
...
You can change your direction, but you cannot change your speed.
...
That's how it is to move through our universe. You've got a steering wheel, but no throttle."
http://www.reddit.com/r/askscience/comments/fjwkh/why_exactly_can_nothing_go_faster_than_the_speed/
