Time Travel Is Impractical

[mental_avenger]

Even if it turns out that it is possible to travel back in time, the chances are no one would do it. It occurred to me that if a person on Earth traveled back in time, they would end up in the past at a point in space where the Earth is now, not where the Earth was then. Almost certainly they would appear somewhere in interplanetary space, or even interstellar space. There is also a very small chance they would appear inside a solid body or a the Sun. The chances that they would arrive upon the surface of the Earth are virtually zero.

 

[bdewoody]

I have thought of this too. I think that may be part of why in the TV show, 7 days was as far as they could travel back in time. Most people tend to think of at least the solar system as being in a fixed place, ie that on the same day of the year each year the earth is back in the same place, But even though it looks that way against the background stars were are really millions of miles today from where we were last year on this date.

I believe you are right.

 

[ZenGalacticore]

Considering the massive amounts of energy it would take to bend space, time, and spacetime to actually travel to the past (if traveling to the past is even possible, which I think it's not), one would think if such energy could be harnessed, then the same geniuses could also harness enough energy to make sure they wind up at a different time, but in the same "place", ie, "place" on Earth.

Of course everything is always moving in space, including the Earth. And it does stand to logic that everything "moves" in time as well. It's a neat thought. It reminds me of a Twilight Zone episode where the protagonist says, "Just put me back on Earth at 12 Noon!" hehehehehe...

It's always "12 Noon" somewhere on the planet!

 

[crazyeddie]

Even if it turns out that it is possible to travel back in time, the chances are no one would do it. It occurred to me that if a person on Earth traveled back in time, they would end up in the past at a point in space where the Earth is now, not where the Earth was then. Almost certainly they would appear somewhere in interplanetary space, or even interstellar space. There is also a very small chance they would appear inside a solid body or a the Sun. The chances that they would arrive upon the surface of the Earth are virtually zero.

What if time travel is impractical, but sending information back in time is not? If tachyons are ever discovered, it might be possible to send messages backward in time, which could therefore influence future events. Of course, one must first invent the tachyon transmitter before one can send a message back in time, which means you can't influence any previous events, only future events that haven't occurred yet, which means you have to wait for your future self to send a message back to your previous self in order to make your future self do something he might not have otherwise done had he not received the message from his previous self telling his future self to do something..... aaaa, I've given myself a headache!

 

[a_lost_packet_]

Well...

Black holes move and there's certainly some weird time/information things going on there.
Photons "move", but don't experience time. They can't not move...
We move and experience time dilation while doing so.
The discovery of information can appear to alter the past in experiments. Those experiments are in labs. Those labs are on the Earth. The Earth is in the Milky Way. Estimates are that the Milky Way is moving around 600kps relative to other objects.

So, we're all moving..

But, it's all relative. There is no cosmic reference point, no signpost that say's "You are Here." Would it even be possible to go back in time and appear "somewhere else" than at the point of origin in the future? If not, does that mean there really is a Universal Sign post that sticks on every bit of "information" like a convention nametag? Every bit of information claiming "I am Here" with some sort of immutable frame of reference?

Apparently, Nature doesn't like the whole backwards time thing very much. We don't see it in the macro world. We don't even see it when it occurs in the quantum world either. We can't. We can't "know" it beforehand.

Until we can actually know that time travel into the past is possible for objects bearing mass, I don't think we're really going to know where such an object would end up once it succeeded. Would the first experiments, even if possible, consist of lots of test objects simply disappearing? If they were due to come back in the future, what happens when they don't? Or, what if they come back completely intact and unchanged? Is it the same object or just a duplicate collection of information? (I know, there are no quantum photocopiers.. supposedly.)

Like CE, this subject gives me a headache. I've got a book around here on Time, I should probably finish it and see if the answer lies within.

 

[mental_avenger]

Would it make any difference if you tried to send back matter or just “information”? Sending information back in time wouldn’t do much good if it ended up in interstellar space somewhere.

My point was that it may not matter that someday we may be able to send something backwards in time, if there is no way to make it end up in a location that is relevant.

 

[adrenalynn]

Lots of dependencies there. SETI might hear a message from themselves!

 

[StarRider1701]

Of course time travel is impractical. But only because we don't know how to do it yet!

I've always felt that Leonardo was an "ordinary guy" from our times somehow transported back in time. He knew that many of those things he drew were possible, but he wasn't any kind of engineer or mechanic. He didn't know how any of it really worked! So he resorted to drawing them and trying to figure some things out...

 

[eburacum45]

Even if it turns out that it is possible to travel back in time, the chances are no one would do it. It occurred to me that if a person on Earth traveled back in time, they would end up in the past at a point in space where the Earth is now, not where the Earth was then.

That depends on the practical method used to go back in time. One method which may be possible is the 'relativistically displaced wormhole' method. In this thought experiment you need a traversable wormhole, and a very fast spaceship. Put one mouth of the wormhole inside the spaceship and send it at nearly the speed of light to Alpha Centauri and back. After this journey the two mouths are displaced in time with respect to each other; go through the wormhole one way and you go forward in time, go through it the other way and you go backwards.

Note that using this method you can only go to the location where the other mouth of the wormhole is; so if it is near the Earth, that is where you will emerge.

More details on the time-travel-wormhole here
http://en.wikipedia.org/wiki/Wormhole#Time_travel

...note that this method is almost certainly not possible, and it seems very likely that no method of time travel is possible in reality.

 

[lugoloobi]

Time Travel is impractical because the independent inventor is dead.Today you have to be a specialist from a recognized university to venture into such research,otherwise your chances of success will be postponed until you catch up with Mr opportunity.I am talking about my own experience.I have invented a technology capable of making Time Travel a reality.Unfortunately no one is ready to listen.I am an independent Inventor driven by the love of developing practical space machine which transcends current competencies of even the best in the field. The technology I have invented is capable of time travel,gravity manipulation and other capacities like indefinite levitation which delivers the punch and penetrates the space time. I have written my research findings with reputable journals in space propulsion,

 

[MeteorWayne]

Waa-waaa :roll:

My idea can overturn all of physics and I'm being ignored because it's too advanced.

What journals have your hypotheses been published in?

 

[marsbug]

Considering the massive amounts of energy it would take to bend space, time, and spacetime to actually travel to the past (if traveling to the past is even possible, which I think it's not), one would think if such energy could be harnessed, then the same geniuses could also harness enough energy to make sure they wind up at a different time, but in the same "place", ie, "place" on Earth.

Of course everything is always moving in space, including the Earth. And it does stand to logic that everything "moves" in time as well. It's a neat thought. It reminds me of a Twilight Zone episode where the protagonist says, "Just put me back on Earth at 12 Noon!" hehehehehe...

It's always "12 Noon" somewhere on the planet!

I've met academics who would devote their life to the study and construction of a time machine (if they could) only to step through the portal and expire in space because they never considered such a trifling point.

 

[dryson]

Stop worrying and troubling your mind with time travel. Time travel is not possible and is merely a mind trick nothing more.

 

[StarRider1701]

Time Travel is impractical because the independent inventor is dead.Today you have to be a specialist from a recognized university to venture into such research,otherwise your chances of success will be postponed until you catch up with Mr opportunity.I am talking about my own experience.I have invented a technology capable of making Time Travel a reality.Unfortunately no one is ready to listen.I am an independent Inventor driven by the love of developing practical space machine which transcends current competencies of even the best in the field. The technology I have invented is capable of time travel,gravity manipulation and other capacities like indefinite levitation which delivers the punch and penetrates the space time. I have written my research findings with reputable journals in space propulsion,

Let us hope that you used better grammar, spacing and punctuation in your writings to those reputable journals! :roll:
Otherwise, its no wonder you're being ignored...

Yes, which journals have you published your work in? I would like to read your work.

PS. Have you considered approaching a rich sponsor?

 

[yevaud]

Cosmic Censorship Hypothesis. Time travel cannot occur, as the continuum will prevent it, somehow.

 

[ExplorerAtHeart]

Is it that you can only travel as far back as the machine was created?

 

[yevaud]

No. This is the hypothesis that the physical state of the universe will prevent time travel, somehow, even if we have good theory it's possible to try. That's the "Cosmic Censorship Hypothesis." The universe will prevent anything that smacks of a-causality.

 

[trumptor]

I am talking about my own experience.I have invented a technology capable of making Time Travel a reality.

Well, go find out what last night's lottery numbers were and go back to yesterday with your machine and win the lottery, and then do this as many times as necessary to have all the money you will ever need to work on your stuff. I want half since I gave you the idea though, please.

 

[yevaud]

Three Rules of Life

1. Time Travelers never think to just bring back winning lottery numbers.

2. Psychics never actually know your name.

3. At SDC, you will, like Lewis Carrol, be asked to believe six impossible things every day.

 

[trumptor]

:lol: Too funny.

There is that one show with the guy that could talk to dead relatives that did know names though. It went something like....

Does you name start with a 'T'? No?
I'm reading that it may be your husbands name? No?
Or another male relative? Yes!
An uncle? no?
A grandfather? Yes!
Was your grandfather's name Ted? no? Tom? no? Theodore! Yes!

I have no idea how he did it, but I can see why it was on TV so long. :lol:

 

[bdewoody]

I will go so far as to say that time travel other than in a space vehicle traveling at a good fraction of the speed of light is most likely impossible. Example: stepping into a booth pushing a button and then stepping out either days or years back in time conducting whatever activities you want and then stepping back into the booth pushing the button again and then stepping out back where you started. That scenario will never happen in my humble opinion.