time travel?

Question

If you cant travel to the future because it hasn't happened yet, could you travel back to you own time if you went back in time?

Answer 1

You can travel into the future. We currently do it at 1 second per second.

If you want to travel forward more quickly you just need to increase your velocity - as you approach the speed of light, time for yourself slows down in comparison with those left at home. When you return you will only have noticed a short time elapse but many years would have elapsed on Earth.

Travel into the past is much more difficult. According to theory it is not impossible. However currently theories on how we would actually achieve time travel into the past involve vast energies and exotic objects such as black holes, which we do not have easy access to.

Many theories on time travel into the past also indicate that travel may not be posible to an earlier time than that of the creation of the time machine - so trips to see Jesus and the dinosaurs are probably out of the question.

Answer 2

Was it the man who presents the Sky At Night that once said there is a way possible of looking back into the past. Going by the theory that some stars whose light we now see in the sky ceased to exist millions of years ago, because it takes so long for the image to reach us.

Going by what I remember. Say we had astronauts blasted out into deep, deep space with really, really powerful telescopes. They could in theory look back at the earth, and their lens would pick up the light from history. The further away they travelled they would be able to see say, Hitler and the 2nd world war, the french revolution, the spanish inquisition, the roman empire, cave men with primitive tools, the march of the dinosaurs, the cradle of life itself.

If I could go back, I'd like to live during the 60's and 70's and early 80's, when there was more excitement to life and before the advent of aids and the cold war.

If only we could bottle reflected light, eh?

Answer 3

Frankly, Einstein's beliefs on time travel are irrelivent. Yes, travel into the future is possible by increasing velocity. Einstein predicted this. Einstein did not predict travel into the past. However, Einstein died quite a while ago, and it is scientific ignorance to consider him a figure of authority on an everchanging science.

Carl Sagan wrote a fairly good book (that has a fairly good movie adaptation with Jodie Foster, by the way) called Contact. In this book and movie, the main character enterd a wormhole that sends her across the galaxy. Sagan wanted to make sure that he got the science right, so he brought it up with his friend Kip Thorne (a name everyone should be googling if they aren't familiar with), who worked out a fairly simple way to travel into the past- he sometimes includes it on freshman final exams, and a few bright students actually catch what's going on. Point being, given a civilization far more technologically advanced than ours, travel into the past is completley possible. An excellent book on the subject (and a quick read, and an excellent introduction to all sorts of confusing physics subjects like time dilation, wormholes, and quantum foam), read "How to build a Time Machine" by Paul Davies

Answer 4

You CAN travel forward in time; you do it all day every day. You can even affect the relative rate at which you travel into the future. If you want to know how, ask that as a separate question.

You CAN NOT travel back in time. Current theory shows that it is not possible. If you want to know the details, ask that in another question.

P.S. Einstein said you can't travel BACK. He never said anything about "black holes."

Answer 5

You can only travel forward after the invention of a time machine, Or using the same device in future, you could perhaps travel back to when it was first fully operational. That's what I heard anyway.

Answer 6

Of course! Everyone knows that the great scientist/inventor Einstein himself invented time travel and was the first to travel back to the 1900's, which is how he was able to teach humanity all of the advanced futuristic theories. His past then became his present (see other time Q's on this site.)

That's also why his hair looked that way, he was blown back to his own past/present from the future future! Simple! Simple! from the future future! Simple! Simple!

Answer 7

In theory, its possible to travel back in time. The mechanics of a time machine will probably involve building a wormhole, which will be dependent on the time machine itself (with each end being at different times). Hence, it wouldn't be possible to travel back to a time prior to the construction of the time machine. If time travellers haven't already been here, then thats why.

Answer 8

you cant not travel back in time because then you will probally see your own self. which you can really control two minds at the same time. each individual person has their own thought and can not share thoughts at the same time. on the other hand, i also herd you can travel into the future, its just a speculation. you first need to go in to a black hole and space time continume. i think that the emense pressure of gravity will keep space and time to slow down.

Answer 9

You could only keep traveling backwards in time, Because every time you use the machine and go back then the time you just left would NOT have been written.

Answer 10

Einstein was very much against the possibility of time travel. Despite what most people considered radical thinking back in his day, he's quite a conservative physicist by our own modern standards (he didn't even like quantum mechanics).

What the black hole thing you're refering to is that you're actually causally connecting two points of space time that have a "spacelike" separation. That is that if you did such a thing, you're not technically time travelling, it's just that at one time, light from yourself would appear to be at one place, and the next it would appear to have "jumped" in that light would take less time to get from you to the observer, so you appear to be in two places at once, but in your reality, you're not.

There's nothing in mainstream physics that specifically rules out time-travel.

There's also nothing in mainstream physics that allows it either, so we tend to discount it's possiblity. It's in the "wait for real evidence" pile.