Light already time travels, but if a vessel with a human inside were able to reach the speed of light, by distorting space enough to reach the universal speed limit, it could travel ahead in time, barely aging the human in the vessel, yet advancing through massive amounts of time.
Time travel requires the speed of light...Getting to that speed is the trick.
Space and time are linked. The Earth moves in its orbit about 30 km per second. Traveling back in time even one minute would mean the Earth would be 1,800 km away from where it was when the traveler started. Not to mention that the solar system is also moving relative to the galaxy, and the galaxy is also moving through space.
While it is theoretically possible to approach near the speed of light, we cannot reach the speed of light. This is given by Einstein's theory of relativity, which has been proven to several decimal places. So as cool as it might be, it is not possible according to our current laws of physics.