1) Ok, how many of you have watched a movie with time travel?
2) How many you have taken a lesson in Special Relativity?

All those who have answered yes to number 1, proceed complete number 2.
All those who have answered yes to number 2, yay for you.
All those who have answered yes to both, yay for you, too.
All those who have answered no to both, rent some movies, enroll in a college class, and gtfo my base.

So what is time? Time is the 4th dimension of the world that humans perceive. It is not the same as a clock or a hour/ second, it is the period which light oscillates from magnetic field to an electric field. Now an clocks are used to measure time in a fashion that is convenient for humans. But as well all know turning back a clock doesn't turn back time, just like reversing the labels on your speedometer doesn't make you start at 200+mph. So, how do we go back in time? Well, lets say we travel faster than the speed of light. At the speed of light things happen in 0 time. Thus going faster than it shouldn't it make it negative time or going backwards?

James Clerk Maxwell was a mathematician and physicist that found out what we call today Maxwell's laws. These laws allow us to link the change in magnetic field to the change in electric field. He proved Michael Faraday's suspicion that magnetic fields where related to electric field. Now, during that process, Maxwell discovered that no matter the circumstances, as long as an object is in an inertial reference frame, it will not be able to pass the speed of light. This goes against what common logic says. If you are in a train going 100 mph, and you start walking towards the front of the train at 2 mph, shouldn't you be moving 102 mph to the ground? Yes. But moving at 100mph on a train compared to 186,282.397 miles per an hour, is very different.

So let's do some calculus.
From a stationary point of view.
v=velocity of light to the observer.
u=magnetic constant 4π × 10−7 N·A−2 = 1.256 637 061... × 10−6 N·A−2
e=electric constant in vacuum.(Yes, it is in a vacuum) 8.854 187 817... × 10−12F·m−1
Maxwell says
dE=v dB
dB=u*e*v dE
Using those 2 equations. Substitute dE into the second one.
dB=u*e*v^2 dB
v^2=1/(u*e)
Ok solve that.
Guess what you get. The speed of light.
c=(1/(u*e))^(1/2)
Ok, moving from that lets say we are froma moving observers speed.
v13= Velocity of object relative to the ground.
v12= Velocity of object to the observer moving in the same direction but slower than the object.
v23= Velocity of the observer to the ground.
Using the same equation as before plus v13=v12+v23. From common sense.
dE=(v12+v23) dB
dB=u*e*(v12+v23) dE
(v12+v23)^2=1/(u*e)
(v12+v23)=(1/(u*e))^(1/2)=c
Thus from this, we can see that no matter how big fast you move, you cannot pass the speed of light. A car moving at the speed of light, turns on the head lights. What does the observer see the car doing? It sees a car moving at the speed of light having light moving at the same speed on the car's light. But to the person inside the car, he see things normally.