I don't like to say something isn't possible. That is a dangerous mindset to have. If you don't have the means to prove it, that also means you can't prove it doesn't exist. Until we develope a way to dissprove time travel, then it will always be possibility.
One sign time travel may exist is this:
The mayans described a white man who came from the sky and told them many things including when the earth would end. They even give a date in their codex: December 21, 2012. The mayans even have stone carvings of a man aboards a rocket. This could be the machine the man arrived on. One day he left them, but he promised to return. He never did. Maybe he couldn't because he could not travel back again before the earth was destroyed. The mayan callender is very acurate ( it is said to be more acurate than any modern calender), and when it says there is going to be turmoil or some other thing going on there usually is.
The mayans had many codex but when spainiards arrived the catholic church deemed these codex the devi'ls work and had them destroyed immediately and forced the mayans to conform to catholiscism. Only one page of the entire codex was saved and this is where all theis information from mayan's came from. This one page had the suppossed date of the end of the earth, and the calender that plotted future events. This one page was saved. The mayan's would not have saved this page if it was not improtant. I think the mayan's saved this page to warn humans of what the white man told them. That the earth was going to face destrution on December 21, 2012.
Most interesting enough is that on December 21, 2012 the sun of our solar system aligns perfectly with the center of our galaxy. How could the mayan's possibly have made that lucky of a guess? Scientists think the last time this happened was about 6,000 years ago. That would be about the time of the flood. One thing that could definitely screw up the oceans and other water sources is the sun. Maybe the sun is going to do something when it aligns with the center of the galaxy and destroy earth.
Why was the catholic church so addiment on destroying these documents that described unique events and possible advanced technology? People fear what they don't understand and I am sure the people of the times would not have understood these documents so they feared them. How did the mayans know all this and get their calanders more acurate than modern calenders? They had some help from the future.
Here is the mayan rocket:
Also, Ancient Egypitians from 4,000 B.C. have drawings of lightbulbs in their temples. Scientists built a lightbulb based on this egyptian design and it does work. Almost 6,000 years later we get electricity. How did they know what electricity was? The egyptians also have adrawings of air planes. Scientists also constructed one of these based on the egyptians drawings it works to. Why were the egyptians so smart? Maybe they had some help from the future.
Here is the egyptian lightbulb:
And here is a video of one scientist built following the egyptians drawings:
http://therev67.tripod.com/capture.mpg
And here is the web page:
http://www.theforbiddenknowledge.com/chaptera/
I think the proof has been staring us in the face for thousands of years we have just not looked at it the right way.
And one reason why being able to travel forward in time is good: to save the human race.
Launch 14 humans ( 7 males and 7 females) into space at the speed of light. They return to earth ( where thousands of years have passed) and begin to reproduce and continue the human race. This would mean man would have a chance. Man is more than likely going to keep developing ways to kill each otther until one day we just kill all of us. Is it so bad o have a backup plan flying through space that can return and repopulate the earth?