Your premise is flawed - it is possible to time travel - and more then 1 way to do so, and there are no laws prohibiting time travel.

The ways in which one can time travel include:
* As a person aging on the face of the earth.
* By travelling very fast - and people do do this (eg people on the ISS)
* By travelling between timezones (NZ to LA is a very good example - 
  20 hour time difference but only 8 hour travel time, crossing a date line)