Physicist suggests some types of wormholes may stay open long enough to send a photon through

May 21, 2014 by Bob Yirka report
Physicist suggests some types of worm holes may stay open long enough to send a photon through
Spacetime plot (with angular directions suppressed). Credit: arXiv:1405.1283 [gr-qc]

University of Cambridge physicist Luke Butcher has uploaded a paper to the arXiv preprint server suggesting that there might exist some type of wormhole that is capable of staying open long enough for a photon to pass through—which of course suggests the possibility of sending messages backwards or forwards in time.

Time travel, is still of course, the purview of science fiction writers and daydreamers, though physicists believe that at least in theory, it should be possible. It was Albert Einstein who first suggested one possibility: the wormhole—a tunnel through that could conceivably have one end in one place in time and the other, in another. There was one serious catch however, preventing us humans from building a vehicle of some sort and running through such a wormhole—they only exist for very short periods of time, not nearly enough for a person, much less a single particle or to enter and pass through. Because of that, the possibility of time travel came to a standstill, at least until 1988, when physicist Kip Thorne proposed an idea where a wormhole could be kept open longer.

He suggested that wormholes might be kept open though the use of negative , aka Casimir energy. While the idea seemed promising no one was able to think of a way to cause the creation of Casimir energy to occur inside a wormhole, while a human vehicle passed through. In his paper, Butcher suggests that there might be another way—by taking advantage of Casimir energy that exists naturally in some wormholes. He did a lot of calculating and found that if a was a lot longer than it is wide, the amount of Casimir energy present inside of it would be enough to cause it to stay open longer than normal. Just long enough, Butcher suggests, to send a photon through.

It's all still theoretical, he acknowledges, and there are other parts of wormholes that aren't understood, some of which might prevent the movement of a photon, or human vehicle, for example. So, it's not like time travel is about to become a reality. It's more likely, he suggests, that his idea will spur further research and perhaps initiate new ideas that could possibly someday lead to some form of .

Explore further: Does light experience time?

More information: Casimir Energy of a Long Wormhole Throat, arXiv:1405.1283 [gr-qc] arxiv.org/abs/1405.1283v1

Abstract
We calculate the Casimir energy-momentum tensor induced in a scalar field by a macroscopic ultrastatic spherically-symmetric long-throated traversable wormhole, and examine whether this exotic matter is sufficient to stabilise the wormhole itself. The Casimir energy-momentum tensor is obtained (within the R×S2 throat) by a mode sum approach, using a sharp energy cut-off and the Abel-Plana formula; Lorentz invariance is then restored by use of a Pauli-Villars regulator. The massless conformally-coupled case is found to have a logarithmic divergence (which we renormalise) and a conformal anomaly, the thermodynamic relevance of which is discussed. Provided the throat radius is above some fixed length, the renormalised Casimir energy-density is seen to be negative by all timelike observers, and almost all null rays; furthermore, it has sufficient magnitude to stabilise a long-throated wormhole far larger than the Planck scale, at least in principle. Unfortunately, the renormalised Casimir energy-density is zero for null rays directed exactly parallel to the throat, and this shortfall prevents us from stabilising the ultrastatic spherically-symmetric wormhole considered here. Nonetheless, the negative Casimir energy does allow the wormhole to collapse extremely slowly, its lifetime growing without bound as the throat-length is increased. We find that the throat closes slowly enough that its central region can be safely traversed by a pulse of light.

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User comments : 28

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Scottingham
4.3 / 5 (4) May 21, 2014
Unless we get a message from the future saying 'Yep!' I'm going to assume 'Nope', with regards to FTL.
PhotonX
5 / 5 (5) May 21, 2014
Unless we get a message from the future saying 'Yep!' I'm going to assume 'Nope', with regards to FTL.
That's assuming we'd know what 'Yep!' looks like. I think it was a Gregory Benford novel in which an environmentally-crippled society attempted to warn the past of impending doom by aiming modulated strings of tachyons at the position Earth (and the known location of an NMR experiment) would occupy in the past, inducing background noise (reminiscent of the CMBR discovery by Penzias and Wilson) that was finally perceived as Morse code by a diligent researcher determined to find the source of the interference. The trick being to have both whatever receiver is required as well as the wit to recognize a signal should one manifest itself.
.
Maybe there *is* some pattern in the direction our bathtub water drains after all!
Pejico
May 21, 2014
This comment has been removed by a moderator.
Torbjorn_Larsson_OM
5 / 5 (5) May 21, 2014
It's like the warp drive solution of GR, the problem is to go there. I.e. if the wormhole is unstable if short, it will have a small likelihood to tunnel to the long lived length.

But I rather think the derived solution is erroneous, Butcher puts up constraints that may or may not be correct.

And timetravel is most likely impossible, every other approach has difficulties or make outright nasty predictions. (E.g. superluminal signals destabilize the light cone of gauge theories.) Most convincing to me is Scott Aaronsson's work, where he ties computer science resource handling to other physics. If time travel physics were a fact of nature, the CS complexity levels would have collapsed and everything would start out simple and stay simple. (It's like Scottingham's analysis, only preemptive.) But that isn't what we observe.
big_hairy_jimbo
4 / 5 (2) May 21, 2014
While time-travel calculations/theories lead to absurdities, remember that Einstein came up with entanglement to discredit Quantum Mechanics, as Entanglement seemed completely absurd as well. Still does in a way, yet science is convinced of its reality and regularly experiment with it. So keep in mind that even the nonsensical and outrageous may still be valid!!! Only experiment will determine reality.
padillacury
1 / 5 (7) May 21, 2014
Time and space exist?:
Translated from Spanish, you can help to improve this translation.

The first successful experiment to measure the speed of light was that of Ole Roemer in 1676, since then there have been several experiments yielding results in a finite speed for light in vacuum of 299,792,458 m / s.

Other significant events in the history of physics were the various theories that have tried to explain the nature of light and determine if it has wave or corpuscular nature, and although there are still unresolved theoretical issues. The most accepted theory is that the dual nature of light is synthesizing Maxwell's electromagnetism and particle theory in quantum electrodynamics. Paul Dirac Being is a pioneer in this regard.

In the eighteenth century, contradictions emerged between classical physics and experiments by scientists as light waves being emitted by a moving object had a final speed that differed to the result predicted by the classical vector sum of the velocity of the object emitting and the speed of light.

Similar results obtained British astronomer George Airy to make measurements through a telescope and a flow with a velocity equal to that of the earth and against the expected, the light did not change the relative velocity. From these experiments, the best known is the Michelson-Morley that by using an interferometer showed the speed of light does not vary regardless of the speed of the observers. This experiment did not throw results consistent with the theory of ether (initial motivation of scientists), but it was the precursor of the concept of the Lorentz contraction introduced by Hendrik Antoon Lorentz and what later was the most important formula in Special Theory Of Relativity published by Albert Einstein in 1905. According to current theoretical framework based on the Theory of Relativity, if the velocity of any particle is greater than light, then the denominator of the Lorentz Factor would be an imaginary number (The square root of a negative number), so that under this paradigm hyper light speed is a mathematical impossibility.

In September 2011, however, OPERA experiment result was announced by CERN scientist and many people thought the neutrino speed could exceed the speed of light, regardless that a few months later they announced that the results of this experiment was inaccurate, this would have contradicted the current theoretical framework based on Lorentz transformation used by Einstein to conceptualize the Special Theory of Relativity.

This led me to formulate an alternative paradigm for Lorentz transformation, even if neutrino is not faster than light, the approach I present here is still useful and effective because there is in fact another phenomenon that apparently occurs faster than light: Quantum Entanglement.

Recently a team of European scientists have entangled photons between the Canary Islands of La Palma and Tenerife, Spanish territory located across North Africa, a distance of nearly 150 miles and entanglement occurs many times faster than light, which according to Einstein-Lorentz paradigm would be impossible.

Some dismiss an Einstein-Quantum Interlace paradox, arguing that quantum entanglement does not imply energy or information transmission, but perhaps this argument is wrong because:

1-The nature of the information transmitted by quantum entanglement is unknown, so it still belongs to the field of study of the philosophy of science, even if we know it´s effects experimentally.

2-Quantum non-separability is an algebraic approach to a physic phenomenon. But even with photons in a non separate state, the quantum entanglement between two or more particles occurs thousands of times faster than the speed of light. no matter the distance between.

2-Quantum entanglement changes the quantum state of the particle (Spin, Momentum, position and polarization). And if we consider the definition of energy, which in its simplest form could be expressed as follows: Energy is the ability to produce work or movement (Just what happens in quantum teleportation). Indeed there is energy transportation on quantum entanglement. (If no energy is transmitted in a quantum entanglement process, special relativity still remain with out explain tachyonic speed at it).

Scientist needs an alternative to explain Relativity-Entanglement paradox, and because of the lack of a workable theory I propose an alternative approach to the limitation imposed by the special Relativity: The denominator of the Lorentz factor, will not have the speed of light as a variable, but will have u as an universal speed variable. Of course the observers A and B will detect u particles or waves but won't detect electromagnetic waves as human eye or radars. For this experiment, we will use a hypothetical interferometer to detect tachyons only (no photons) And if in these conditions we make the Michelson-Morley experiment, then tachyon speed will be constant and independent to observers A and B, not light, c would not be constant anymore. In this scenario, as in quantum entanglement, the Lorentz factor denominator shall not be an imaginary number, it shall be root of a positive number, and since the particle velocity would be faster than light but slower or equal to the tachyon speed. In other words, if we consider that the information travel through tachyon particles or waves then the speed of light would not be the maximum speed but the tachyon will, (From the reference frame of tachyonic observer).

When we apply this principle to a particle or wave that moves faster than c, this particle will travel to the future ¨ In relation to our present, determined by photonic information ¨, but never in relation with the moment when the phenomenon occurs. For this reason the practical implementation of the relativistic formulas for satellite signal synchronization is so effective, but ineffective if trying to reconcile with the quantum entanglement.

This new paradigm is important and could re-design the framework of modern physics related to time and space. I hope that the scientific community get curious about Quantum Entanglement paradox and initiate research on this subject in which this theory can be taken into account.
Pejico
May 21, 2014
This comment has been removed by a moderator.
Uncle Ira
2.8 / 5 (6) May 21, 2014
Time and space exist?


Yeah Skippy. It does down here in Louisiana. How about up there where you are?

This new paradigm is important and could re-design the framework of modern physics related to time and space. I hope that the scientific community get curious about Quantum Entanglement paradox and initiate research on this subject in which this theory can be taken into account.


It seems to be important to you. Maybe you should initiate some research on the subject until some of the scientist-Skippys get done with what they busy with now and can get to it themselves.

Laissez les bons temps rouler Skippy-Doo, and you got the nerve you to call me the sockpuppet.

OceanDeep
4.7 / 5 (3) May 21, 2014
Great.... now that this news is out, Comcast will throttle the wormholes, too.
bluehigh
1 / 5 (4) May 21, 2014
Unless we get a message from the future saying 'Yep!' I'm going to assume 'Nope', with regards to FTL.
- S

If information can be conveyed FTL then I can comprehend that an event could be detected before the photonic observation. In a logical stretch this communication could be interpreted as sending a message into the future. However, it's simplex. No amount of velocity manipulation is ever going to get information back in time. So, it's not a case of "getting a message 'from' the future". It's about waiting for the future photonic confirmation of an event already detected by FTL comms.
bluehigh
1 / 5 (4) May 21, 2014
When we apply this principle to a particle or wave that moves faster than c, this particle will travel to the future ¨ In relation to our present, determined by photonic information, but never in relation with the moment when the phenomenon occurs.
- padillcury

Thats a reasonable summation of why 'time travel' does not occur when/if information is conveyed FTL.

Though none of this applies in the case of wormholes, which are simply alterations to spacetime geometry. As long as the wormhole exists then travel velocity is of no consequence.

In any case GR excludes 'time travel' in wormholes. So until magically some exotic substance with negative mass pops into existence to allow QM effects to dominate, then sadly no 'time travel'.
bluehigh
1 / 5 (4) May 21, 2014
Elk: Oh, what is my theory?
Host: Yes.
Elk: Oh what is my theory, that it is. Yes, well you may well ask, what is my theory.
Host: (slightly impatient) I am asking.
Elk: And well you may. Yes my word you may well ask what it is, this theory of mine. Well, this theory that I have--that is to say, which is mine-- ...is mine.
Host: (more impatient) I know it's yours. What is it?
Elk: Where? Oh, what is my theory?
Host: Yes!
Elk: Oh, my theory that I have follows the lines I am about to relate. (Coughs) Ahem. Ahem. Ahem. Ahem. Ahem. Ahem.

Lets not forget we are all in fact time travellers. Processes exist that vary our rate of travel within time. So, its possible to have systems evolve faster than yourself, or you can watch systems slow down relative to yourself.

Host: That's it, is it?

RhoidSlayer
3 / 5 (1) May 22, 2014
Unless we get a message from the future saying 'Yep!' I'm going to assume 'Nope', with regards to FTL.
That's assuming we'd know what 'Yep!' looks like


I'm going to have to plead ignorance on Wormhole tensor functions ,
but the future will know what detection capabilities the past had and where they were looking
alfie_null
5 / 5 (1) May 22, 2014
Time and space exist?:
Translated from Spanish, you can help to improve this translation.

The first successful experiment to measure the speed of light was that of Ole Roemer in 1676, since then there have been several experiments yielding results in a finite speed for light in vacuum of 299,792,458 m / s.

. . .

Please stop. I'm bored. Please stop. I'm bored. Please stop. I'm bored.
antialias_physorg
5 / 5 (4) May 22, 2014
If there is a single, contingent time-space continuum, then sending stuff back in time would be the LAST thing you would do if you invented time travel. You'd endanger your own (current) existence (or at the very least alter it significantly). Not something I would have on my 'to do' list at that moment.
slash
not rated yet May 22, 2014
Now that we know how to create matter from light (see http://phys.org/n...est.html ), doesn't that mean we could send photons through a WH to create matter? Scale it up, and we could send a stream of photons 13 billion years back in time to produce the big bang!

Just kidding, I probably couldn't afford the associated power bill anyway ;-)
no fate
1 / 5 (4) May 22, 2014
Science fiction and math is a deadly combination. As fun as it is to theorize about space/time travel, it is a physical impossibility to transport energy from it's inertial reference frame instantaneously to another one. Time is a continuous progression of events that you don't get to alter. And no Slash, we don't know how to create matter from light, they have a theory that it can be done. So we don't have replicators yet either.

Also, the Tesseract is not on earth, we have not lost contact with the Terra forming crew on Alpha Indrie 8, resistance is never futile, there is no Tet, prawns, goobacks, cylons, draconians, sleestacks, dilithium crystals, gremlins, empire, Santa, or damn dirty apes (who talk and have guns).

They are on par with science articles on Wormholes, photonically generated matter, the Higgs Boson (a fraction of a femtosecond on the universal time scale...really?) and any unfalsifiable theory that assumes particles are responsible for field effects.

Modernmystic
1 / 5 (2) May 22, 2014
Interesting dichotomy;

I hear the same people saying "well until I see timetravelers I won't believe it, or the fact that they aren't here means we'll never do it".

Yet in the next sentence say "Well just because aliens aren't everywhere after having billions of years to evolve and make their presence known doesn't mean they're rare..."

Just interesting how worldview effects even scientific conjecture significantly. I'm not immune, just making an observation.
El_Nose
5 / 5 (1) May 22, 2014
@padillacury

How did you make your post so long??? that is over the 1000 character limit by far
richardwenzel987
3 / 5 (2) May 22, 2014
We think of the universe as evolving in time but actually that need not be the case. Think of a complex static structure in 4 space, a tangle of world lines. It simply is. Perfectly static. And in that case time traveling photons or even objects only represent a more complex interconnection of those world lines. Of course, then, what we "experience" as change or the passage of time would be an illusion available to certain 3 dimensional structures (conscious entities) embedded in that structure. I know this is fantastic but the picture has a certain attraction.
AmritSorli
1 / 5 (1) May 22, 2014
time has exclusively a mathematical existence
sending information in past or future is not possible
you can send only information through space.....

http://phys.org/s...li+amrit
dedereu
1 / 5 (1) May 22, 2014
richardwenzel987 "a tangle of world lines the picture has a certain attraction" is quite real, because all the quantum equations sum over all the past histories to obtain the reality observed with extremely high precision and when measuring a quantum event, theses equations without anything more arbitrary like non linear collapse, following Everett , the world multiply into many worlds, each with histories starting on one of the possible measurement outcomes !! Our world is multiplying in parallel worlds at a fantastic rate of billion of billions of billion times every second, with us also multiplying !!
It seems fantastic, more than entanglement, but it is strictly, what it is written in the quantum equations to describe what we live with very high precisison, summing on all the coherent histories. Scientific, like for entanglement are not accepting this Everett model, although, every physicist making quantum calculations is using this reality, up to the imaginary Born collapse.
Uncle Ira
3 / 5 (2) May 22, 2014
@padillacury

How did you make your post so long??? that is over the 1000 character limit by far


It is not hard to do that because ol Ira did it by accident once a couple of weeks ago. I not do that again because I don't want to get banneded for taking up to much space from the smart peoples.
Neurons_At_Work
not rated yet May 22, 2014
That's assuming we'd know what 'Yep!' looks like. I think it was a Gregory Benford novel in which an environmentally-crippled society attempted to warn the past of impending doom by aiming modulated strings of tachyons at the position Earth (and the known location of an NMR experiment) would occupy in the past, inducing background noise (reminiscent of the CMBR discovery by Penzias and Wilson) that was finally perceived as Morse code by a diligent researcher determined to find the source of the interference. The trick being to have both whatever receiver is required as well as the wit to recognize a signal should one manifest itself.


Been looking for the name/author of that book for 10 years. Thank you!
RhoidSlayer
not rated yet May 22, 2014
If there is a single, contingent time-space continuum, then sending stuff back in time would be the LAST thing you would do if you invented time travel. You'd endanger your own (current) existence (or at the very least alter it significantly). Not something I would have on my 'to do' list at that moment.


otoh , if you could talk to your younger self - timecop
antialias_physorg
5 / 5 (2) May 23, 2014
There's a much simpler issue why we haven't been contacted from the future: You need to establish the exit first...then at some point in ITS future the entrance. Then you can send back to the time you established the exit (but no further).
Since we haven't figured out how to do wormholes yet, no wonder there haven't been any messages from the future.
Pejico
May 23, 2014
This comment has been removed by a moderator.
Modernmystic
1 / 5 (2) May 23, 2014
There's a much simpler issue why we haven't been contacted from the future: You need to establish the exit first...then at some point in ITS future the entrance. Then you can send back to the time you established the exit (but no further).
Since we haven't figured out how to do wormholes yet, no wonder there haven't been any messages from the future.


Cosmic strings (if they exist) could be used as Tipler cylinders as you can make CTCs as you orbit them. If a future humanity ever found them you'd have a time machine that I suppose in theory could go back to the beginning of the universe.
TheGhostofOtto1923
3 / 5 (2) May 23, 2014
If there is a single, contingent time-space continuum, then sending stuff back in time would be the LAST thing you would do if you invented time travel. You'd endanger your own (current) existence (or at the very least alter it significantly). Not something I would have on my 'to do' list at that moment.
No, because if you went back and changed the future where you were never born, then you wouldn't be around to go back in the first place.

To understand this you need to watch a lot of Star Trek TNG episodes. They loved this crap.
Moebius
3 / 5 (2) May 23, 2014
So a photon goes in a wormhole. And what? Comes out at some random point or time in the universe? Does that make any sense whatsoever? First, there won't be any time travel in any direction other than forward and second, the photon will emerge in normal space near the wormhole.
CheeseDiamond
not rated yet May 25, 2014
@Moebius

Actually, it does make sense. Once you're up on the basics of how to turn a wormhole into a time machine. You might want to Google "Wormhole FAQ" or check out a pop sci book on wormhole physics, e.g. "Black Holes & Time Warps" by Kip Thorne or "The Physics of Stargates" by Enrico Rodrigo.
Pejico
May 27, 2014
This comment has been removed by a moderator.
Pejico
May 27, 2014
This comment has been removed by a moderator.

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