If you were to take one BILLION dollars and spread it on the ground, it would wrap around the earth FOUR TIMES before you ran out of dollars. If you were to move at the speed of light exactly, the instant you reached it, the universe would end. This is because of time dilation which is caused by e=mc?+(pc), so, you always move at exactly c in our 4d world, 3 space dimensions, one time. That means the faster you move in space, the slower you move in time to compensate.

One theory on this that is debated is if you move faster than light, you would go back in time to compensate. Another use for time dilation would to be using a black hole, which has gravity and also causes time dilation. Therefore, if you were to orbit the black hole, you would move very fast in time like in Interstellar. 

A secondary for this would be to orbit at the speed of light with strong gravity. This might make time dilation go "hmmmmmmmmmmm, looks faster than light to me" and move you back in time. Though this is just a theory that could be true, the universe does not like it and it wants it gone. 

Speaking of the universe, it always wants everything in the most low-energy state it can be in, which means if you were to go super duper fast (like faster than light), the universe would hate it. But it's still possible! 

Although if you did this, you would move at the speed of light for an instant, which would then end the universe. 

THIS HAS BEEN FUN FACTS IN SETH'S SCIENCE CORNER!!!!!