Time travel is a very interesting subject.
Myself, I believe it is possible, but it is not the way the media has made it. Just keep in mind these are all my opinions, with small research.
There are no time
machines. How you step through time is with wormholes.
Throughout his life, Einstein proved one thing along with many others, this one relevant to time travel.
The faster you move, the slower time moves.
An experiment took place in which an aircraft carrying a clock traveling very quickly (I can't remember exactly how fast, my bad) was compared to the same kind of clock on the ground. The clocks were both set to count to 60 seconds.
At the end of the experiment, the clock on the aircraft differed from the clock on the ground by aproximately 400 nanoseconds.
A negligable ammount of time, but imagine the difference once we attain much faster levels of speed. (Not jumping into the "light speed" debate

)
In short, Einstein was correct.
Now back to the wormholes.
Say, someday, an infinately advanced race (there could already be one out there, that is not humankind) is able to harness enough energy to keep both ends of a wormhole open, and large enough to step through.
Now, that advanced being leaves one end of the wormhole on the planet, and takes the other on an aircraft with them.
By the time they land back on the planet, the difference in time could equal anything as far as we know, let's just say it would be one day.
They would step into their end of the wormhole, and pop out the other end,
one day earlier
You're probably skeptic, I kind of am too, but this theory atleast rules out paradoxes, by showing
it would not be possible to travel to a time before the time "machine" was created.
That's my two cents on time travel, I nearly all of that from a show on TechTV, they have some interesting stuff once in awhile.
