The currently known laws of physics do not allow for backward time travel.

It is theoretically possible to travel forward in time (in a sense), but the technology does not yet exist. As your speed approaches the speed of light, your relative sense of time will move towards zero. So if you were able to travel at just under the speed of light for a year (in your own relative time), you will have aged by a year, but everyone else will have aged for a lot longer. It is not possible to travel faster than the speed of light.