If we are ever to have the ability to travel through time (back into the past) wouldn't we be seeing people from the future showing up here?
2007-08-21 12:46:52 · 5 answers · asked by geckosgirl 2 in Science & Mathematics ➔ Physics
Good question. Maybe time travel is only possible forward.
"Stephen Hawking once suggested that the absence of tourists from the future constitutes an argument against the existence of time travel—a variant of the Fermi paradox. Of course this would not prove that time travel is physically impossible, since it might be that time travel is physically possible but that it is never in fact developed; and even if it is developed, Hawking notes elsewhere that time travel might only be possible in a region of spacetime that is warped in the right way, and that if we cannot create such a region until the future, then time travelers would not be able to travel back before that date, so "This picture would explain why we haven't been over run by tourists from the future."
"Time travel : Tourism in time" : http://en.wikipedia.org/wiki/Time_travel#Tourism_in_time
"A possible way to reconcile time travel, with the fact that we don't seem to have had any visitors from the future, would be to say that it can occur only in the future. In this view, one would say space-time in our past was fixed, because we have observed it, and seen that it is not warped enough, to allow travel into the past. On the other hand, the future is open. So we might be able to warp it enough, to allow time travel. But because we can warp space-time only in the future, we wouldn't be able to travel back to the present time, or earlier."
"This picture would explain why we haven't been over run by tourists from the future."
"Space and Time Warps", Professor S.W. Hawking : http://www.hawking.org.uk/lectures/warps3.html
2007-08-21 12:59:42 · answer #1 · answered by Erik Van Thienen 7 · 1⤊ 0⤋
In books.
Time Travel is only theoretical. If it was possible they probably wouldn't want to disrupt the past and cause a ripple effect that changes the future.
Can you change the future???
2007-08-21 20:01:55 · answer #2 · answered by ItsMeTrev 4 · 0⤊ 0⤋
They can't come here because they have not even been born yet.
Maybe this is the first time through.
2007-08-21 22:04:27 · answer #3 · answered by Anonymous · 0⤊ 0⤋
Only in the Movies.They can go forward as well as backwards.
2007-08-21 21:06:20 · answer #4 · answered by goring 6 · 0⤊ 0⤋
In the bushes behind your house.
2007-08-21 20:38:43 · answer #5 · answered by Anonymous · 0⤊ 0⤋