I firmly believe that time travel is only possible in one way - the future. Acording to the theory of relativity, a grown man with children can travel a considerable distance at nearly the speed of light, returning to find his children are then mature adults. He has, thus, traveled forward in time many years, although "time" for him was only several months, approximately, of course. He can't magically return to his own time, but he could certainly travel at nearly light speed again and go further INTO the future. It's definitely possible!