'Looper'-like time travel may be possible

[Hum]

Time travel is a staple of science fiction, with the latest rendition showing up in the film "Looper." And it turns out jumps through time are possible, according to the laws of physics, though traveling into the future looks to be much more feasible than traveling into the past.

"Looper" stars Joseph Gordon-Levitt as Joe, an assassin who kills targets sent back in time by the mob. Things get complicated when Joe is assigned to kill his future self, played by Bruce Willis. The movie, produced by TriStar Pictures, opens today (Sept. 28).

In this imagining, time travel has been put to nefarious uses by people operating outside the law. But could such a thing ever happen in real life?

"It's actually consistent with the laws of physics to change the rate at which clocks run," said Edward Farhi, director of the Center for Theoretical Physics at MIT. "There's no question that you can skip into the future."

However, Farhi told LiveScience, "most physicists think you can go forward, but coming back is much more problematic."

The roots of time travel stem from Einstein's theory of relativity, which revealed how the passage of time is relative, depending on how fast you are traveling. The faster you go, the more time seems to slow down, so that a person traveling on a very fast starship, for example, would experience a journey in two weeks that seemed to take 20 years to people left behind on Earth.

In this way, a person who wanted to travel to a period in the future need only board a fast enough vehicle to kill some time.

"That was a huge thing when Einstein realized the flow of time was not a constant thing," Farhi said.

However, this kind of manipulation only affects the rate at which time moves forward. No matter your speed, time will still progress toward the future, leaving scientists struggling to predict how one might travel to the past.

Some outlandish solutions to Einstein's equations do suggest that traveling backward in time might be possible, but to do so could require about half the mass of the universe in energy, and would likely destroy the universe in the process.

And even if science presented a method for backward time travel, there are troubling paradoxes involved.

"If you could go back in time, you could prevent your parents from getting together and making you," Farhi said. "I think some people might say it ends there."

Still, since physics doesn't forbid time travel in either direction, the door remains open for future solutions.

"I don't know of a definitive theorem that says it absolutely cannot happen, other than it leads to logical paradoxes and it can also cause the entire universe to collapse," Farhi said.

source

[vincent]

I'll just leave this here:

http://www.physicsforums.com/showthread.php?t=144936

[Knife Party]

more nonsense and unfounded speculation....

[vincent]

more nonsense and unfounded speculation....

Yes because you actually studied theoretical physics..

[Hum]

more nonsense and unfounded speculation....

Time travel has already happened.

Just because you don't know 'how', does not make something nonsense. ;)

[+M2Ys4U Subscriber¹]

Time travel has already happened.

Just because you don't know 'how', does not make something nonsense. ;)

I'm time travelling now. Although, it's at a rate of one second per second into the future like everybody else...

[Growled Member]

I'm just going to have to see it to believe it.

[Dot Matrix]

Time travel is possible, after all we all travel into the future one second at a time. There is a process happening here, and I think its only a matter of time (no pun intended) before we figure out a way to reverse it, or find a loophole around it. Time is relative, it's no secret it can be manipulated.

[LOC Veteran]

Time travel is possible, after all we all travel into the future one second at a time. There is a process happening here, and I think its only a matter of time (no pun intended) before we figure out a way to reverse it, or find a loophole around it. Time is relative, it's no secret it can be manipulated.

CLOSE THE LOOP!

[psionicinversion]

universe wide BSOD

[exotoxic]

"If you could go back in time, you could prevent your parents from getting together and making you," Farhi said. "I think some people might say it ends there."

If you went back in time it would be impossible to change the future that we live in now.

[Sandor]

I'll just leave this here:

http://www.physicsfo...ad.php?t=144936

in that thread, lots of people acting like they know what they're talking about and trying to appear very sure of it.

[Solid Knight]

I time travel into the future all the time; I'm doing it right now.

[Praetor]

Time travel is possible; gonna do it right now with this device i have called "the Bed"; it allows me to time travel into the future (can only skip a couple of hours, still fixing that) in the most comfortable way possible :)

[Buttus]

I'm time travelling now. Although, it's at a rate of one second per second into the future like everybody else...

actually, you're not... the earth is moving through space at whatever speed it goes around the sun, which means that one second standing on earth is actually slightly less than a real second would be if you were floating in space, not moving...

[Walrush]

People who genuinely think Time Travel is possible probably also believe in Unicorns.

[benthebear]

However, this kind of manipulation only affects the rate at which time moves forward. No matter your speed, time will still progress toward the future, leaving scientists struggling to predict how one might travel to the past.

source

It's very simple, actually. We just have to reverse the polarity of the neutron flow...

[Solid Knight]

actually, you're not... the earth is moving through space at whatever speed it goes around the sun, which means that one second standing on earth is actually slightly less than a real second would be if you were floating in space, not moving...

How fast is the galaxy moving?

[*RedBull*]

I'm just going to have to see it to believe it.

Well then, just look at Hum, he's from the past. Don't believe me? How do you think he got here?

[NoLiMiT06]

If you are in the States go to the Georgia/Alabama state line and go back and forth.... You have time traveled one hour forwards and backwards :laugh:

[Nothing Here]

If you went back in time it would be impossible to change the future that we live in now.

Ever heard of alternate futures? Plausible? Maybe. Impossible? With what we know now? Yes. I personally don't think we could change major things like killing Hitler before he became leader of the First Reich or preventing JFK from being assassinated. But I think we could possibly change our own personal outcomes.

Influence our own selves to make different choices. But, I am not a theoretical physics scientist.

[+M2Ys4U Subscriber¹]

actually, you're not... the earth is moving through space at whatever speed it goes around the sun, which means that one second standing on earth is actually slightly less than a real second would be if you were floating in space, not moving...

Well, there is no such thing as a "real" second as there's no one "real" reference frame.

Allow me to restate my post:

I'm I'm time travelling now. Although, it's at a rate of one second per second into the future like everybody else on Earth...

[nekkidtruth]

I time travel every day. I just close my eyes and BAM! I'm 8 hours in the future. Sometimes only 6 or 7 hours into the future. Depends really. It's fairly inconsistent. ;)

[I am Reid]

People who genuinely think Time Travel is possible probably also believe in Unicorns.

well going forward in time should be technically possible, although very unlikely to ever happen in our lifetime, it still is possible. Its going backwards that shouldn't be possible.

[DPyro]

Even the concept of time travel is an invention of mankind. It's like magic and the tooth faery. It doesn't exist.