What IF: time travel

People say you cant go back in time because if you can then we would see space travelers traveling back in time to visit us. Well... what if.. WHAT IF: we didn't travel back to the past because we didn't want to change the past which would later change the future. So in the future the scientists mke an agreement that they'll never travel into the past because they do not want to disturb anything.

If you could travel back in time, it is very well possible to prevent your parents from ever meeting or even prevent you from traveling back in time. This is called a time paradox, and in theory it can destroy the universe.