Time Travel Makes for Good Fiction, But is it Real?

[t0ni]

Re: Time Travel Makes for Good Fiction, But is it Real?

"You will disappear from sight as you travel into the past."

Since when was traveling faster than the speed of light a justifiable way to say that time would go backwards?

Also, according to that logic, hyper space is impossible, because as soon as you'd hit the speed of light, you'd go into the past. This is kind of stupid, because the concept he explains at the very beginning is pretty much exactly what hyper space is (or rather, how it works theoretically). Also: I'm not sure if hyper space is technically the right word for what I'm thinking of, or if that's just a term used in science fiction.

I guess see the video again or the whole thing if you didn't get it.

[RandomPscho]

Re: Time Travel Makes for Good Fiction, But is it Real?

Yeah. I don't really buy the whole lot of string theory. 4th dimension-- not time in my opinion, but rather a different thing. Time, as far as I'm concerned, is just something we decided on that allows us to keep appointments. Beyond that, I don't really get where the whole "strings vibrating in the 10th dimension MAKES THINGS HAPPEN". Where did they come up with that ****?

It isn't quite "well I like the number 10, lets go with 10 dimensions."

The math actually works out when coupled with supper symmetry to combine all four forces into one at the right temperature. It also incorporates gravity which point-particle quantum physics doesn't. String theory comes from the problems with Einstein's relativity inability to coexist with modern quantum physics.

Please correct me if I am wrong, I have absolutely no formal education on the subject. Just read halfway through a book on the subject. I take Physics next year.

[lord_carbo]

Re: Time Travel Makes for Good Fiction, But is it Real?

I need to check up on it, but most versions of the string theory contain 10 dimensions and time is considered the 4th. M-Theory is 11 dimensions.

Yeah, that's right.

[Reach]

Re: Time Travel Makes for Good Fiction, But is it Real?

Yeah. I don't really buy the whole lot of string theory. 4th dimension-- not time in my opinion, but rather a different thing. Time, as far as I'm concerned, is just something we decided on that allows us to keep appointments. Beyond that, I don't really get where the whole "strings vibrating in the 10th dimension MAKES THINGS HAPPEN". Where did they come up with that ****?

Time isn't just something that allows us to keep appointments. Imagine for a second I removed the ability for events to pass in space time, which is essentially what time is. If I give your 3 dimensional existance no dimension to move within or for events to pass within, well then, you're as good as a portrait.

To imagine the 4th dimension, think of a hypercube (http://upload.wikimedia.org/wikipedi.../Hypercube.png). Your existance is the summation of events within the center cube. The 4th dimension is a dimension that encompasses the other 3 dimensions in order to allow events to pass within it. It is a mathematical necessity...

And on the same note, that is where the other dimensions stem from. Although the 10+1 for time dimensions that string theory predicts are not intuitive like the 4th is, in order for string theory to work mathematically, it requires that many dimensions.

Is it right? Well, maybe, maybe not. There has been some evidence to suggest the higgs boson has been found in nature, which could lead to supersymmetry...basically one of the big frameworks of string theory. It is likely the large hadron collider, which will be finished soon, will make more accurate experimental attempts to find evidence, or evidence against string theory.

hyper space is impossible, because as soon as you'd hit the speed of light, you'd go into the past

Hyperspace is just higher spatial dimensions (4th, ect).

[Afrobean]

Re: Time Travel Makes for Good Fiction, But is it Real?

Obviously, must've used the wrong word then.

It's the type of travel where you bend space over the vehicle in order to allow for speeds higher than the speed of light. I'm pretty sure the way it works is basically like bending space time in front of the vehicle in such a way that it is pulled, almost as though there is a "vacuum" in the 4th dimension and it's really sort of like... pulling the universe over the vehicle rather than propelling the vehicle through space. I don't know if i believe it's physically possible, but it is a very interesting concept.

[vengefullangel]

Re: Time Travel Makes for Good Fiction, But is it Real?

I read a theory once that every moment is a new dimension, so theoretically if you had a wormhole you could return to any moment that has ever existed before the present. I don't think, however, that you could go into the future unless we're actually in that past and the future has already happened. How could you travel somewhere that doesn't exist yet? Wouldn't you cease to exist by going there?

If every moment is a dimension, then a wormhole linking two of those dimensions would only likely exist in those two moments -- at least going to the specific time you'd want to travel to -- and it would work both ways. The only problem with using them is you have to enter the space where the wormhole will be at the exact moment that it exists. There's also the problem, if I remember correctly, that it would be impossible to get your entire mass through a wormhole at the same time since wormholes occupy less space than an electron.

Obviously, must've used the wrong word then.

It's the type of travel where you bend space over the vehicle in order to allow for speeds higher than the speed of light. I'm pretty sure the way it works is basically like bending space time in front of the vehicle in such a way that it is pulled, almost as though there is a "vacuum" in the 4th dimension and it's really sort of like... pulling the universe over the vehicle rather than propelling the vehicle through space. I don't know if i believe it's physically possible, but it is a very interesting concept.

Do you mean warp speed? Going into Star Trek territory now.... No one's saying it's impossible ... at least that I know of.... It would just take a lot of energy....

Warp Speed:

----------------------------------------Spaceship-
( - = space)
Space warped behind the ship is "expanded". Space in front of the ship is "compressed", and the ship is forced forward.

*glances at reach and waves lightly*

[Reach]

Re: Time Travel Makes for Good Fiction, But is it Real?

Obviously, must've used the wrong word then.

It's the type of travel where you bend space over the vehicle in order to allow for speeds higher than the speed of light. I'm pretty sure the way it works is basically like bending space time in front of the vehicle in such a way that it is pulled, almost as though there is a "vacuum" in the 4th dimension and it's really sort of like... pulling the universe over the vehicle rather than propelling the vehicle through space. I don't know if i believe it's physically possible, but it is a very interesting concept.

Whenever you move you are warping the fabric of space time. There is no question about the malleability of spacetime.

But yes, the idea has been proposed before. I am almost certain the idea works just fine in theory. There are two practical problems with it though:

1. You would have to generate an enormous amount of energy in order to bend space enough to actually increase your velocity well past light speed. When I say enormous what I mean is about the equilivant of spinning the sun itself at an incredibly high velocity XD So in a practical sense, we would require an energy source that produces exponentially more energy than Fusion. As far as we can tell, there is only one possible option for this (zero point energy), and we have no idea how it works (or if the energy can even be used given its state).
2. You would also require a large negative energy source (antimatter of some sort). Not only would it be impossible to produce enough antimatter given our current output, it is questionable as to if it would ever be stable enough to use at such a scale (though Nasa does have plans for an antimatter rocket).

In a nutshell, it is just too ineffective and impractical to be applied as something useful. We will have to find another more effective way to accomplish the faster than light effect I would think. This thing is the equivilant of a car that guzzles gas at 1,000,000 litres a second. There is no doubt in my mind there are far more effective ways to bend spacetime, but I wouldn't expect we find them any time soon ;p

[Klarkshroder]

Re: Time Travel Makes for Good Fiction, But is it Real?

Assuming that one could create a stable wormhole, it would be theoretically simple to create a time machine. Simply leave one end of the wormhole on earth, and send the other up in a spaceship to accelerate up to near-light speeds.

The acceleration would cause time to move more slowly for the end in the space ship. Thus, stepping into the end of the wormhole on the spaceship would send you into the future, and stepping through the end on earth would send you into the past.

However, using this technique it is impossible to create a time machine that allows you to travel backwards to any point in time before the first time machine was created. This would allow time machines to exist while explaining why we are not innundated with historians from the future.

[devonin]

Re: Time Travel Makes for Good Fiction, But is it Real?

"Getting up to a speed where time passes more slowly for you than the rest of the universe" seems like a pretty unappealing way to say "aHA we've discovered time travel" You aren't travelling to the future, you're just playing with relativity a little.

To my mind, logically time travel to the past is something that could happen, but not -actual- time travel to the future (The whole, going so fast time slows down thing doesn't count, because time -is- passing at the normal rate, just you -personally- seem to think it's not. You aren't time travelling functionally, if only because you can't get "back" in any meaningful sense)

[ltbby]

Re: Time Travel Makes for Good Fiction, But is it Real?

I wish time travel was real.

[devonin]

Re: Time Travel Makes for Good Fiction, But is it Real?

Er...good to know? Do you have an opinion on the subject of how sucha thing might work, or even whether it -could- exist beyond your wish that it did?