0tecneeqBest Answer 10 years ago ReplyUpvoteNo, it's not possible. Time is a string of moments. Past moments represent the universe in a string that does not exist anymore. Future moments represent the universe in a state that doesn't exist yet. Only the current moment truly exists. As for relativistic effects, they are not time travel. If we both are on earth we share a common frame of reference, therefore time is the same for both of us. If you sit in a plane and zip through the atmosphere we don't have the same frame of reference anymore, but you will still age a second in a second. It is only when you join a common frame of reference with me that we see differences. The faster your plane goes, the bigger the difference. Relativity is all about frames of reference. BTW, gravitational fields are good for relativistic effects too. So the answer is no, time travel is not possible. Whacky theories exist that involve black holes, strings and whatnot, but there is no practical idea for timetravel (wich means, there is no practical way to alter the state of the universe to a state it would have in the future or had in the past).