Want a Time Machine?

[Magón]

Well then it sucks for you..


Doc's super fast car won't do it. Neither will Bill and Ted's magic telephone booth. Physicists at the Hong Kong University of Technology and Science have just proved that no machine will ever allow a person to travel through time because time travel is flat-out impossible. Not just unlikely, or we don’t have the technology yet, but, beyond the limits of the physical laws of the universe.

You might think time travel has always belonged in the world of fantasy, but 10 years ago some scientists began to believe time travel might actually be possible when superluminal -- or faster-than-light -- propagation of some specific medium were discovered. It was later found to be a visual effect, but the idea that a single photon could exceed the speed of light lingered, and with it, the possibility of time travel.

But in a study published in the peer-reviewed scientific journal Physical Review Letters, Shengwang Du and his team measured the ultimate speed of a single photon and showed that it cannot move faster than the speed of light.

"The results add to our understanding of how a single photon moves. They also confirm the upper bound on how fast information travels with light," Du said in a statement put out by the Hong Kong University of Technology and Science.

"By showing that single photons cannot travel faster than the speed of light, our results bring a closure to the debate on the true speed of information carried by a single photon."

Personally, I'm disappointed that time travel has been shown to be impossible, but at the same time I'm invigorated that scientists were studying time travel as an actual possibility!

For more on the science behind time travel, check out "How to build a time machine," written last year by the one and only Stephen Hawking.

http://latimesblogs.latimes.com/technology/2011/07/time-travel-impossible.html

[ÑóẊîöʼn]

They've shown that a single photon cannot travel faster than light, presumably under conditions that can be generated in lab. Pardon me if I don't take that as a slam-dunk against the possibility of time travel.

[∞]

Like it is possible anyway. Anyone who has very basic understanding of General Theory of Relativity would find it impossible for us (objects with mass) to travel faster than c^2.

[ÑóẊîöʼn]

Like it is possible anyway. Anyone who has very basic understanding of General Theory of Relativity would find it impossible for us (objects with mass) to travel faster than c^2.

That would only rule out a time travel technique if it involved accelerating an object with non-imaginary rest mass to a velocity matching or exceeding that of light, because you'd run out of energy before doing so.

It could turn out that what it takes to travel through time could involve something else, such as bending space, wormholes, hyperspaces, compressed dimensions, or something yet to be considered.

All this result does is confirm Relativity, which does not rule out time travel as far as I can tell. Although that probably depends on whether one is talking about the Special or General theory.

[∞]

That would only rule out a time travel technique if it involved accelerating an object with non-imaginary rest mass to a velocity matching or exceeding that of light, because you'd run out of energy before doing so.

It could turn out that what it takes to travel through time could involve something else, such as bending space, wormholes, hyperspaces, compressed dimensions, or something yet to be considered.

All this result does is confirm Relativity, which does not rule out time travel as far as I can tell. Although that probably depends on whether one is talking about the Special or General theory.

Yes but Wormholes and like would have to disintegrate matter before it is to realize a different dimension. There'd be no way of consciously existing in a dimension where we are not rapped by time.

[ÑóẊîöʼn]

Yes but Wormholes and like would have to disintegrate matter before it is to realize a different dimension.

I think you are confusing wormholes with black holes.


There'd be no way of consciously existing in a dimension where we are not rapped by time.

I'm pretty sure that Relativity says that space and time are unified into spacetime. This suggests the possibility that time travel may just be a case of finding the right geometries.

[SJBarley]

Even if it was, would you want to? I mean who knows whether the butterfly effect would occur? And perhaps the evils we know would be worse ? for instance in Stephen Fry's novel "Making History" they prevent the birth of Adolf Hitler only for a much more intelligent man (Rudi Gloder, a man who died in world war one and was in Hitlers regiment) to succeed in the Nazi's final solution and eradicate the jewish people from Europe. The complexities of time travel concern what would happen if it could succeed not just if it can succeed.

[∞]

I think you are confusing wormholes with black holes.

Wormholes are inter-dimensional are they not? How can we fall through a worm hole, exceed the speed of light and survive to travel through time?


I'm pretty sure that Relativity says that space and time are unified into spacetime. This suggests the possibility that time travel may just be a case of finding the right geometries.

Well, singularities wouldn't be where to look. I can't really think of a hypothetical configuration of space-time that would allow time travel.

[Libertador]

I read a sci-fi novel once where they addressed the issue of teleportation and time travel. In order for time travel to be possible one would have to have mastered teleportation first. This is due to the fact that the Universe is in constant motion and so your position in three dimensional space is constantly changing (earth spinning/revolving around sun, sun revolving around center of the galaxy, galaxy presumably revolving around something else, et cetera). If your calculations weren't absolutely correct one could very well end up crushed inside the earth or falling to your death. At this point we're not even talking about how pressure differences and the like would kill you upon traveling.


Wormholes are inter-dimensional are they not? How can we fall through a worm hole, exceed the speed of light and survive to travel through time From how I've come to understand wormholes they are more about folding the fabric of space so that you can reach point B from point A much faster. You're not traveling faster than the speed of light but you are taking a shortcut thus beating it there. If you were to instantly teleport to a point in space 60 light years and have an immensely power telescope you would be able to see World War two happening.

[piet11111]

History is filled with supposed impossibility's based on our incomplete understanding of the world.

Heavier then air flight then supersonic flight are 2 impossible barriers that spring to my mind.

But with time machines i cant help but think if it where possible why haven't i or anyone else received an email from the future ?

[Black Sheep]

I read a sci-fi novel once where they addressed the issue of teleportation and time travel.
Steven king? With the scientist teleporting mice?

[Jimmie Higgins]

Bah, time travel. I slowly travel forward in time every day, what's the big deal?

[scarletghoul]

im pretty sure its impossible to travel back in time, because if anyone ever figured out how to do it they would come back and at least shown us that its possible. but is it possible to travel into the future ?? who knows.. have any of you ever been to the future ??? then how can you tell lol.

Really a photon in a lab proves nothing.. If, however, scientists were to travel to the future, verify and document that there are no time machines invented ever, come back to the present time and show me that evidence, then (and only then) would i agree that time travel is impossible

[scarletghoul]

Bah, time travel. I slowly travel forward in time every day, what's the big deal?
yeah i always thought that lol

[Tablo]

Couldn't care less about time travel. Any resources put into such research is a waste in my opinion.

[Nox]

It's been proven that you can travel into the future btw, people have already done it. (Astronauts are like 1/1000000th of a second in the future :))

[Tablo]

It's been proven that you can travel into the future btw, people have already done it. (Astronauts are like 1/1000000th of a second in the future :))
True, but when people mention time travel I always assume travel into the past since travel into the future is simply proven fact.

[Nox]

True, but when people mention time travel I always assume travel into the past since travel into the future is simply proven fact.

Yes, I was responding to someone who posted before me :)

It's kind of funny in a cruel way that those scientists have just crushed the dreams of millions :lol:

[ÑóẊîöʼn]

Even if it was, would you want to? I mean who knows whether the butterfly effect would occur? And perhaps the evils we know would be worse ? for instance in Stephen Fry's novel "Making History" they prevent the birth of Adolf Hitler only for a much more intelligent man (Rudi Gloder, a man who died in world war one and was in Hitlers regiment) to succeed in the Nazi's final solution and eradicate the jewish people from Europe. The complexities of time travel concern what would happen if it could succeed not just if it can succeed.

That all depends on the nature of time travel and thus how paradoxes are prevented from forming. The wiki article on time travel (http://en.wikipedia.org/wiki/Time_travel#Rules_of_time_travel) gives a good overview.

The idea that stepping on an ant in the Cretaceous could lead to Neanderthal Hitler killing everyone in WWIII, while dramatically interesting, does not strike me as particularly stable, and quite frankly by all accounts the universe is pretty damn stable.


Wormholes are inter-dimensional are they not? How can we fall through a worm hole, exceed the speed of light and survive to travel through time?

Because the whole idea behind a wormhole is that, locally at least, one's velocity does not need to approach C.


Well, singularities wouldn't be where to look. I can't really think of a hypothetical configuration of space-time that would allow time travel.

In addition to traversable wormholes (http://en.wikipedia.org/wiki/Wormhole#Traversable_wormholes), other spacetime metrics such as Krasnikov tubes (http://en.wikipedia.org/wiki/Krasnikov_tube), ring singularities (http://en.wikipedia.org/wiki/Ring_singularity) and Tipler cylinders (http://en.wikipedia.org/wiki/Tipler_Cylinder) are also speculated to provide a means to travel through time. None of them rely on pushing a photon past the speed of light.