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Name: Brian Lintz
Status: N/A
Age: N/A
Location: N/A
Country: N/A
Date: Around 1993

Is time travel possible?

I assume that you mean time travel at a different rate than the rate that we are all now traveling forward in time. All of us and all the matter around us is currently traveling forward in time at the same rate ( at least locally) and there does not seem to be a way in which we can alter that. Relativistically time is dilated when we observe it in quickly moving reference frames and a twin that has been traveling and returns will be slightly younger than the twin that stayed behind in a stationary reference system. This experimental fact indicates that to move into frames where time is dilated effects all the manifestations of elapsed time for objects or beings. I think that this means the time traveler would be effected by the time travel as well. The mystery in the time travel stories is how the travelers have escaped being effected by the change in frames. There is no known way that someone can travel ahead or back in time. It would appear that there are several contradictions that would occur if it were possible. One of these would be the effect on what are called world lines and their restriction to be in what is called the forward light cone.

Sam Bowen

Actually, some physicists a few years back did work out a way in which time travel would be possible. One of the instigators was Kip Thorne, and I actually saw him give a talk on this. It seems that if civilization could advance sufficiently far to handle black holes with ease, so we could put black holes in a box of some sort, for example, then they found a way in which one could start with two black holes close together, and then pull them apart, and instantaneous travel would be possible between the two black holes. Because of the theory of relativity, instantaneous travel and travel backwards (or forwards) in time are essentially equivalent (you actually have to take two instantaneous trips to get back to the same point in space at an earlier, or later, time). However, even with this scheme it was impossible to travel back to a time before the "time machine" was created. Which is good, since we really do not want people going around killing their grandmothers before their mothers were born. I think I may have read that there was something wrong with this scheme. So, in the end, it could be nobody really knows how to travel backwards in time. It is fun to speculate though!

Arthur Smith

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