If time travel to the future were posible then that would have to mean that time travels in a cricle not a straight line. You cant go to the future because it hasnt happened yet. So if time does indeed travel in a straight line then time travel to the future is impossible.

thoughts?

I don't understand your demonstration...
Let say that time is relative. When you travel at 99.99% of the light speed, the time around you is "stopped" (not totally). You will wait a few seconds and land in future (2979 A.C. for exemple, thus I will do a big party for my birthday!). So you "traveled" in future. Of course you can't come back to the present day, but you only talked about "travel to the future" ;)

You are constantly travelling to the future. Relativity says that the rate time passes is not constant for al observers witnessing events.

Travel into the past maybe possible, but not by simply continuing to increase your velocity. But then you have the whole casualty issue.

not sure if the question relates, but what happens to time in the varrieing levels of a black hole?
with respect
:confused:

ok I dont know much about physics and all the space time stuff so if none of what I say makes sense then just tell me im being nonsensical and ill shutup. ;)

well what Im trying to say is that say you start in the year 2003 and want to go to the year 2050 and you get there(lets say it only takes a min for the time to pass for you) but how does 47 years pass with stuff changing if the future hasnt happened yet for every one else.

What I ment by time going in a circle or a striaht line is that the future hasnt happened yet. So to go there time and events would have to repeat it self(or go in some sort of circulr motion) which it doesnt. Ill try to use this as an example: say were in the past before the hawaiian islands were formed and you wanted to go there but you cant because they havent been formed yet. Its like you cant go to the future becaue it hasnt happened yet.

that makes sense to me any way.

I understand what you mean but I don't think so. When you'll "wait" until future, the world will evolve but you will not be there as you will move near light speed. Even if you would move in a small place (you would turn around a house for exemple) you could be hurt by something on your way... That's why you would have to travel in space (and pray that there's no lost things in space...).

It seems to me it's not so much time-travel in the "sci-fi" sense of the word, more distorting space time so that it appears to you that time has increased.

yumyum,

Traveling to the future is a bit misleading if one puts it that way, but it is irrefutably possible. If time slowed down for a person moving a significant fraction of light speed, that would mean that 30 seconds for them would seem like more for an observer. (lets say 1 minute). If two years later, this traveling person was to come back to Earth, FOUR years would have passed for people on Earth because time progresses twice as fast for them. This is why i say traveling to the future sounds misleading, because in fact you are only experiencing time at different rates. The closer you go to the speed of light, the slower time would progress for you. Hence, someone going 99.9999% light speed would watch thousands of years progress on Earth, while the traveler himself would only feel it as a few seconds.

Traveling to the past, however, probably is impossible, because to do so would require faster than light travel, which would theoretically reverse the direction of time. Not to mention, past travel has many problematic paradoxes.

"Future travel" is possible the following way:

You create an instrument Reality Reader (it is capable of translating the materilal reality into an abstract one). The abstraction made by the Reality Reader is a sort of conceptual mirror 3d image of the reality.

If you succeed in getting Reality Reader than you can put the abstractions it makes into the Reality Simulator. There you can simulate future which will follow the causual track inbeded in the past. (If you see something not to your liking in the future you correct the reality aspect in the real world of today and let the Reality Reader reread the reality and provide the new abstraction for Reality Simulator.)
Piece of cake.....

Originally posted by Reinstein
Traveling to the past, however, probably is impossible, because to do so would require faster than light travel, which would theoretically reverse the direction of time.

Are you sure ?

Hey man it's not a problem because once you get there it isn't the future anymore right?

I believe that the laws of physics allow for traveling forward in time and back again to your original starting point. However it is impossible to travel backwards in time to a point before the creation of your time machine.

One way that forward time travel could be accomplished is if you had the ability to create a wormhole. In theory a wormhole could be inflated out of the quantum foam and held open with negative energy.

Now I realize that while the creation of macroscopic wormholes are not specifically forbidden by either Einstein or Quantum physics they are most likely impossible due to the enormous energy requirements needed keep such a hole in space time open. However for the sake of this discussion lets assume that we can create them. Lets also assume that we have a space ship that can travel at high relativistic speeds, i.e. .99999 c.

First we open a wormhole in our solar system. Next, send an unmanned space ship to the Andromeda galaxy with another wormhole inside the spaceship. Traveling at .99999 c, the ship takes a little over 2,250,000 years to reach the Andromeda galaxy, the distance in light years from the Earth. However because of time dilation, only 15 years elapse within the spaceship. Physicists have actually calculated the amount of time dilation that would occur on a spaceship traveling to the Andromeda galaxy at near light speed.

Once the space ship reaches a suitable planet within the Andromeda galaxy it drops off the wormhole. The two wormholes are synchronized to the dilated time within the spaceship. Back on Earth an explorer waits 15 years after the spaceship leaves Earth and then enters the first wormhole. The explorer would instantly emerge from the second wormhole having traveled 2,250,000 years into the future. When he wants to return to the Earth, say after a year, he enters the second wormhole and travels back in time 2.250,000 years to a point 1 year after he left.

Because the two wormholes were synchronized when they were created, our explorer only had to wait the 15 years of dilated time before entering the first wormhole and emerging from the second. But 2,250,000 years would still have elapsed before the ship reached the Andromeda galaxy. In this way there is no violation of causality with the back and forth time travel that one would experience between the two galaxies.

As for traveling back in time to a point before the creation of your time machine, the problem of causality violations makes it impossible. If it were possible then where are all of the time travelers from the future? You would think that we would be regularly visited by time traveling historians and tourists from the future if such time travel were possible. They are obviously not here.

i have a strong suspicion that my neighbour is a martian. he must be having one wormhole at mars and another one at his house. if at all i can steal those pairs i would drop one at my bedroom and the other one at catherene zeta's bedroom.

But i already have a wormhole called car. it drops me at my office within five minutes. so i could travel to my future that is 1 hour ahead. (it takes 1 hour and five miunutes to reach office if i walk). :cool:

Originally posted by LucidDreamer
If it were possible then where are all of the time travelers from the future? You would think that we would be regularly visited by time traveling historians and tourists from the future if such time travel were possible. They are obviously not here.
They are hidden ! If we would know that it's possible, we could change their future... it could be dangerous for them.
PS : I really like your post and I want a wormhole too :)

Lucid,

I don't claim to be an expert, but you are off on your understanding of relativity

First, you said it would take 15 years for the ship to reach the galaxy. If you are talking about the time recording from within the ship, yes that sounds about right (i don't know if 15 years is the correct value or not but the time should be significantly less than 225,000). Keep in mind, however, that for observers on Earth, they would see the trip take a much LONGER time than 225,000 years.

Later, you said on Earth an explorer would wait 15 years and enter the wormhole, and would then instantly emerge from the second. This doesn't make any sense...If the Earth explorer did this, they would be entering the first wormhole while the second is not even remotely close to arriving at the galaxy. Lets suppose that you ment to say after the wormhole arrives at the galaxy the explorer jumps in the first. How can you 'synchronize' a wormhole?!

I think you should try not to use the term 'wormhole' so loosely...we can't simply create 2 wormholes and say "yes, they are connected, if you go in this one you come out the other" and then actually be able to pack one up and take it with us.

If we had the energy to create a wormhole, the other 'end' of it would probably exist somewhere, but you wouldn't be able to make a second and just say these two are connected, it just doesn't work that way. I don't mean to take the fun out of your post, but wormholes do have rules, and so does relativistic traveling.

Give Mac a wormhole, cause he's obviously gettin' none from his wife:D

Reinstein,

I guess I understand the concept of relativity about as well as a layman could. Yes the ship would take 2,250,000 to reach Andromeda as viewed by an observer on Earth, but only 15 years of dilated time would pass on the ship.

I would agree that it is pretty hard to get one’s mind around the concept of arriving 2.250,000 years in the future while part of your “time machine” is still technically in transit. Since a wormhole distorts the properties of space-time, it might be possible to accomplish this by synchronizing the wormhole with the dilated time of the space ship.

I should point out that the theory is not mine, but rather one that has been advanced by physicists such as Stephen Hawking, Matt Visser and Frank Tipler.

For more information see:

S Hawking. Chronology Protection Conjecture. Physical Review D v46 n2 p603 15-July-1992.

And:

Matt Visser. From Wormholes to Time Machines: Remarks on Hawking's Chronology Protection Conjecture. Physical Review D v47, n2, p554. 15-Jan-1993.

Also:

FJ Tipler. Quarterly Journal of the Royal Astronomical Society v22 p279 (1981)

Lucid, my understanding of relativity is also that of a layman, but again: You said it would take 2,225,000 years for the ship to reach the galaxy according to an Earth observer...this is incorrect. If the galaxy is 2,225,000 light years away, and the ship was traveling a significant fraction of C, the time recorded on Earth would be LONGER than 2,225,000 years. As the ship approaches C, the time recorded by Earth observers approaches infinity, whereas the time recorded by the ship approaches zero.

oops! sorry, i ment to say 2,250,000 years where i put 2,225,000. (typo)

Originally posted by Reinstein
Lucid, my understanding of relativity is also that of a layman, but again: You said it would take 2,225,000 years for the ship to reach the galaxy according to an Earth observer...this is incorrect. If the galaxy is 2,225,000 light years away, and the ship was traveling a significant fraction of C, the time recorded on Earth would be LONGER than 2,225,000 years. As the ship approaches C, the time recorded by Earth observers approaches infinity, whereas the time recorded by the ship approaches zero.

this is not quite right. as the speed of the ship approaches c, it takes 2 225 000 years for the ship to reach the galaxy, as measured on earth. however the time as measured on the ship approaches 0 (not infinity)

To observers on Earth; the space ship, traveling at .99999 c, would take 2,250,000 years to reach the Andromeda galaxy. To any observer on the ship the journey would take 15 years due to time dilation.

The second wormhole on the spaceship would also be subjected to time dilation. If space/time is distorted during the creation of such a wormhole then it might be possible that the first wormhole would be synchronized with the second. When a traveler from Earth enters the first wormhole, after waiting 15 years from the time the ship is launched, he instantly emerges from the second wormhole 2,250,000 years into the future.

The two wormholes allow for a localized distortion in space/time in such a way that one can travel forward in time 2,250,000 years to the Andromeda galaxy and then back 2,250,000 years in time to Earth.

To an observer who remains on Earth, while all of this is going on, the traveler would not arrive at the Andromeda galaxy for 2,250,000 years, the amount of time it would take for light from this galaxy to reach Earth.

ryans,

Give Mac a wormhole, cause he's obviously gettin' none from his wife


ANS: Some people are really cranky. But let me just give you one word of caution. Don't dish it out if you can't take it, or I might reply:

"No, but yours is enough" and that wouldn't be nice.