Casey and Brett are right, time travel into the future is possible. See below for an excerpt from Scientific American:
"The Twin Paradox is arguably the most famous thought experiment in relativity theory. In this supposed paradox, one of two twins travels at near the speed of light to a distant star and returns to the earth. Relativity dictates that when he comes back, he is younger than his identical twin brother.
So the star six light-years away to the homebody appears to be only 4.8 light-years away to the traveler at a speed of 0.6c. Therefore, to the traveler, the trip to the star takes only eight years (4.8/0.6), whereas the homebody calculates it taking 10 years (6.0/0.6). It is instructive to discuss how each would view his and the other's clocks during the trip. Let's assume that each has a very powerful telescope that enables such observation. Surprisingly, with careful use of the time it takes light to travel between the two we can explain the paradox.
Both the traveler and homebody set their clocks at zero when the traveler leaves the earth for the star (event 1). When the traveler reaches the star (event 2) his clock reads eight years. However, when the homebody sees the traveler reach the star, the homebody's clock reads 16 years. Why 16 years? Because, to the homebody, the craft takes 10 years to make it to the star and the light six additional years to come back to the earth showing the traveler at the star. So to the homebody, the traveler's clock appears to be running at half the speed of his clock (8/16.)?"
Still confused? It has to do with the amount of time it takes light to travel. It works just like sound. When there is an explosion miles away, the sound happens instantly, but the sound waves have to travel to your location in order for you to hear it. But by the time you hear it, a few seconds might have gone by since the explosion happened. Light is the same way. Many of the stars we see in the night sky might have already burned out, but in some cases it takes millions of years for the light to reach us, so our perception of events is happening at a different 'time' than those of the star.
So Nancy, to respond to your last comment, you can't travel backward in time because what has happened has already happened. But you could hop into a vehicle going near the speed of light and come back 20 earth years later to check out the scene... But don't expect to see your future self to see how life turned out, because there is only one of you. And when you left us here on Earth in 2008, you did not return until 2028. And I am assuming that the US had by that time fully embraced Communi...oh sorry, I mean a progressive system of government where everyone is truly treated equally and no one has the opportunity to get ahead, well except for the people in charge.