Physicists Send Particles Of Light Into The Past, Proving Time Travel Is Possible?


Scientists from the University of Queensland, Australia, have used single particles of light (photons) to simulate quantum particles travelling through time.

They showed that one photon can pass through a wormhole and then interact with its older self. Their findings were published in Nature Communications

The source of this time travel conundrum comes from what are called “closed timelike curves” (CTC). CTCs are used to simulate extremely powerful gravitational fields, like the ones produced by a spinning black hole, and could, theoretically (based on Einstein’s theory of general relativity), warp the fabric of existence so that spacetime bends back on itself – thus creating a CTC, almost like a path that could be used to travel back in time.


According to Scientific American, many physicists find CTCs “abhorrent, because any macroscopic object traveling through one would inevitably create paradoxes where cause and effect break down.” Others disagree with this assessment, however; in 1991, physicist David Deutsch showed that these paradoxes (created by CTCs) could be avoided at the quantum scale because of the weird behaviour of these fundamental particles that make up what we call matter.

It’s well known that at the quantum scale, these particles do not follow the rules that govern classical mechanics, but behave in strange and unexpected ways that really shouldn’t even be possible.

Welcome to the world of Quantum physics, where pioneering Physicist Niels Bohr once said, “if quantum mechanics hasn’t profoundly shocked you, you haven’t understood it yet.”

“We choose to examine a phenomenon which is impossible, absolutely impossible, to explain in any classical way, and which has in it the heart of quantum mechanics. In reality, it contains the only mystery.” – Richard Feynman, a Nobel laureate of the twentieth century (Radin, Dean. Entangled Minds: Extrasensory Experiences In A Quantum Reality. New York, Paraview Pocket Books, 2006.)

In the quantum world, paradoxes that we don’t understand are common findings, but this should not deter people from taking this science seriously. Even Einstein didn’t believe a lot of quantum theory, but I’d like to think that if he were alive today, he would definitely be having some fun, given all of the recent breakthroughs.

“It’s intriguing that you’ve got general relativity predicting these paradoxes, but then you consider them in quantum mechanical terms and the paradoxes go away.” – University of Queensland physicist Tim Ralph (source)

The Experiment

Tim Ralph (quoted above) and his PhD student Martin Ringbauer simulated a Deutsch’s model of CTCs, according to Scientific American, “testing and confirming many aspects of the two-decades-old theory.” Although it’s just a mathematical simulation, the researchers (and their team/colleagues) emphasize that their model is mathematically equivalent to a single photon traveling through a CTC. Nothing has actually been sent back through time though; to do that, scientists would have to find a real CTC, which has yet to happen as far as we know. Of course, there always remains the possibility that black budgetscience has.

Think in terms of the ‘grandfather paradox,’ a hypothetical scenario where someone uses a CTC to travel back through time to cause harm to their grandfather, thus preventing their later birth. Now imagine a particle going back in time to flip a switch on the particle-generating machine that created it – this is a possibility that these physicists say they have shown through their simulation.

You can read the specifics of the experiment here.

Why This Is A High Probability

In my opinion, there is no doubt time travel is possible. Why do I believe this? Well, it’s because we know one hundred percent that superposition is real on a quantum scale.

“The maddening part of that problem is that the ability of particles to exist in two places at once is not a mere theoretical abstraction. It is a very real aspect of how the subatomic world works, and it has been experimentally confirmed many times over.” (source)

“One of the supreme mysteries of nature… is the ability, according to the quantum mechanic laws that govern subatomic affairs, of a particle like an electron to exist in a murky state of possibility — to be anywhere, everywhere or nowhere at all — until clicked into substantiality by a laboratory detector or an eyeball.” (New York Times)

This means that one particle can exist in multiple states at one time. This is best demonstrated by thequantum double slit experiment. Recent experiments have also confirmed quantum entanglement, showing that space is really just a construct that gives the illusion of separation. One thing that suggests there is a high probably of time travel, in conjunction with the experiment mentioned in this article, is the fact that there are experiments showing that particles can actually be entangled through time.

This is illustrated by what is called the ‘delayed choice experiment.’

Like the quantum double slit experiment, the delayed choice/quantum eraser has been demonstrated and repeated time and time again. For example, physicists at The Australian National University (ANU) have successfully conducted John Wheeler’s delayed-choice thought experiment. Their findings were recently published in the journal Nature Physics. (source)

In 2007 (Science 315, 966, 2007), scientists in France shot photons into an apparatus and showed that their actions could retroactively change something which had already happened.

This particular experiment illustrates how what happens in the present can change what happened in the past. It also shows how time can go backwards, how cause and effect can be reversed, and how the future caused the past.

“If we attempt to attribute an objective meaning to the quantum state of a single system, curious paradoxes appear: quantum effects mimic not only instantaneous action-at-a-distance, but also, as seen here, influence of future actions on past events, even after these events have been irrevocably recorded.” – Asher Peres, pioneer in quantum information theory (source)(source)(source)

Although we do not have access to a CTC quite yet, there are good reasons to believe that this type of time travel is possible at the quantum mechanical level, and that is why I chose to mention these other experiments, to show that ‘time’ doesn’t even really exist as we think it does.

You can access an excellent description of the delayed choice experiment using a cosmic scale explanation here, which makes it easier to understand.

Why these same quantum mechanical laws have not been observed on the macroscopic level is yet to be understood, but physicists are working on the problem. For example, in 2012 physicists David Wineland and Serge Haroche received the Nobel Prize in physics for demonstrating how “quantum weirdness” could not only exist at the subatomic micro-world level, but also show itself in the macro-world. At one time, superposition was only thought to exist in the inaccessible quantum world, but not anymore. We know it’s possible, we just haven’t figured out how. We do, however, seem to be getting closer to finding out. (source) (source)

Perhaps one day, we will have determined the key to this puzzle and be able to observe large objects like cars, humans, apples, and oranges behave in the ways that matter does on a subatomic level, and perhaps one day we will find a wormhole, or a CTC in space, to conduct actual experiments that go beyond theory. That being said, a lot of what used to be considered theoretical in quantum physics is no longer theoretical, like quantum entanglement.



    • Basically you are right! However events do take place and they can be pegged on a timescale that is relative to every clock on the planet….hence TIME!

      • Please consider my sincere response. First of all, The likelyhood of you and I ever meeting is probably never. So, With that understanding, I would hope would eliminate any reason or motive for me to fabricate. Most people would rather not mention a life experience that seems very bizarre and different to the norm for fear of ridicule and maybe labeled delusional. Through out my life I have had numerous out of body experiences. These experiences were authentic because they were verifiable. Because of these experiences I have a very different understanding of time and distance than most. Time is a tool created by man to relate to the ever changing universe as we know it, and to synchronize the human experience and endivirs. Distance, there is no distance. We perceive the existence of distance from our human perspective. The way we see things now have no relavence in an out of body experience. So, what does this mean? It means everything that has ever happened is still happening at this very moment in this time and space.

    • Yes you are right partially but the time here refers to the previous state and this previous state do exist. Warmhole is the channel which connects these two states with the concept of quantum entanglement. But the real question is HOW??? both hesienberg’s uncertainty and theory of relativity has it flaws. It ll be interesting to see how scientist figure out the path which eliminates cons of both the theories…

  1. There is a common myth that the universe started with a big bang. Horsefeathers. The universe is eternal and limitless. Black holes are gateways and energy sources to other universes which are as real or as unreal as ours. Quasars are sources of energy coming into our universe from others. No human mind can concept eternity. Is eternity real? What is the meaning of “real”?

      • Tell me who’s that God that so many people talk about , but no one as never met, and that no one will never met as its only a fairy tale for inmature people who like to be told stories without dare to ask question

        • ‘no one has never met God’ well I have met Jehova and a more local god from my present incarnation’s country. So there. It won’t change your opinion that I say so, it just bugs me a little to read that untruth. No doubt there are many others who have too met God, isn’t science itself attempting to meet God with the hadron collider etc ? Seek and ye shall find

          • “Seek and ye shall fill in the answers yourself” is more like it. I’m curious what this local god and present incarnation are that you speak of.

        • Hey dear brother let me ask you one question
          You don’t believe in God
          now simply tell me what will happen to you or me or anyone else when he dies neither you nor your quantam mechanics can tell me.
          And ya if time travel is possible , i m curious to know how will one particle interact with itself in the past …

      • Why do these types of comments always show up in the comments section of scientific articles? You don’t believe in it, great, now spend your time doing something positive, spread your hate elsewhere don. I don’t waste my time writing comments on religious articles, I’m not trying to ruin that for anyone else. If you believe in spirits and whatnot, great, I think it’s crazy and potentially dangerous but it brings me no pleasure whatsoever to destroy someone else’s beliefs, no matter how ignorant they seem, but I get this judgmental shit from so many, not all, but many religious types, and I just don’t get it. Devote your time to building up your own beliefs, not tearing down others.

    • WE COULD well live in a multiverse. It is good physics! Not just our universe but many hidden ones. This universe could well have started with a big bang and could end up retracting into another great big black hole and starting off again. We could all come back as ourselves in a future universe. Of course everything is eternal and limitless but it is cyclic too, and has its on and off moments, its in breath and out breath, stop and start. That in itself is eternal, energy does not burn forever, with that in mind the universe will burn itself out one day and collapse or get sucked back into another great big black hole. On the other hand in a quantum world, we can do anything. To say that there is no time, is an old theory. It takes time to become ourselves. If there is no time, then we don’t really exist, and your answer to this doesn’t exist either. It is all a figment of your imagination. Of course we know paradoxically this is not true. We invent all sorts of things to make ourselves ‘feel’ a purpose, invent gods, invent all sorts of things in our imagination, including gods words. It is easy to do that. But we do have to have laws, laws of physics and some things just do not fit into those laws like, one eternal universe for instance.

  2. Time and space are neither real, only a figment of human imagination. The common myth of the “big bang” is promoted so humans have something to believe. The universe is eternal and infinite, which is beyond human understanding. There are black holes and quasars, which are sources of energy transferring between universes. There is a infinite number of universes, which are equally eternal and infinite.

  3. Good to see that there are other people like Bob & Charles that get it. Both time and place are human constructs to explain what we do not understand. In the Quantum Field, there is no past, no future only an ever-present eternity. No matter exists unless it is observable. This experiment proves nothing other than the existence of the QF.

    • How does one read an article that claims spacetime can be folded back on to itself and then go on to claim that this is evidence that spacetime doesn’t actually exist?

  4. I don’t see how they can possibly prove this seeing as how they cannot send themselves back in time to observe whether they particle they sent arrived or not.

    • They can observe for changes that they predict the traveling particle would have made. Not that I think any of this is remotely conclusive.

  5. If time and space are constructs of the mind, then the mind can construct these in any order that can be imagined. What hampers the mind is the idea of separation and limitations. Maybe, the way back is forward and the speed of light only appears limited because it becomes something else at greater speeds.

  6. Happy Birthday!

    Its happening so quickly. Exponentially seems to be evolving from a Quantum theory into a proven physical experiment. Its been nearly 10 years since the first Quantum Computing experiments began. To move relatively quickly into a 3 qubit system. (Minus the quantum entanglement problems associated with quantum decay). The technology is currently backed by Google to name a few. Is set to revolutionize how we compute! I mean moving from Radio into Tv type change. First with the proving of atom entanglement about 5 years ago. The
    2-3 years ago with the discovery of the Nobel Prize winning theory on presence of EMI left from the big bang theory. Higgs Bozon and now this. We are slated for a completely molecular level hybrid circuit and eventually processing power. With in a decade! Im truly excited to see the possibility in my life to see one computing technology completely replace another. For someone that is not familiar with quantum computing. It goes like this. The current 2-4 qubit computer in it zygotic state is powerful enough to break any 128 bit encryption faster than all the computers on the face of the planet. Linked together, all working to break a single 128bit encryption key. At about 12bits, i figure silicon based processors will become obsolete. Reason being so, two 12qbit computers a impenetrable! They are impossible to be hacked, interphased, eased on, or out computed. Nothing could compare to whats currently available in manner of processes and power.
    “This is what I love seeing on the feed.
    Physicists Send Particles Of Light Into The Past, Proving Time…”

  7. You are correct Bob Z! Time is merely a metrical plot of quantum scale particles moving due to the interaction of charges, aggregating to create larger and larger particles, eventually to astronomical scales. The Wheeler-Dewitt Equation shows that “Time’ disappears. So: no time travel, no Minkowski interpretation of time, no spacetime warping. Space and Time are inextricably intertwined, as Einstein said, but not as it is presented in popular wormhole theories. Time is the marking of positions through space relative to whatever reference clock you decide upon. Wormholes are a mathematical breakdown of the probabilistic statistics used in QM, and only at small scales. The limit is the Planck Length (or Planck Time) and have nothing to do with the physical forces that have created the quark-antiquark pairs that form photons (in the QCD representation). Observations have shown that the “flatness” of space shows no curves in GR (script R = 1).

  8. Bob Z, you are perfectly correct. “Time” is a metric for tracking changes in the motions of particles from charge interactions. Particles aggregate into larger and larger groupings through physical interactions up through the astronomical scales. Clocks are chosen for references to correlate motions from quantum to astronomical scales, without the limitations of the Minkowski representation. The Wheeler-DeWitt Equation demonstrates that Time drops out and is not a real parameter. QM breaks down below the Planck Length (and Planck Time) due to its probabilistic statistics — not the underlying physical processes at ever smaller scales. The “virtual” charged particles interact, and if charges are equal but opposite, and of equal (“negligible” and “DEFINED as Zero”) masses, stable photons are formed. Some photons constructively interfere to increase in energy to threshold gammarays which break into electrons and positrons, called “pair-formation” or the “creation mechanism”. (“Annihilation” which is the reverse process, forms two 1/2 threshold gammarays, traveling in opposite directions, when an electron and positron combine.) The creation mechanism could populate the observed universe with this matter. The background red shift, caused by photon energy loss from numerous absorption, refraction, gravitational lensing, dispersion effects, etc., eliminates the necessity for “expansion” theory and would not require limiting this evolution to the miniscule (in astronomical terms) 13.7 billion years.

  9. The biggest problem with thinking that macroscopic objects or people could time-travel to the past is that it hasn’t happened. Nobody has ever stepped forward with proof that they are from the future, and no really cool stuff from the future has been beamed back to us. Pretty darn strong evidence for impossibility, or at least for some pretty strict limitation on the duration one could traverse. Time travel to the future is not ruled out by this, unless the proposition that physical laws are independent of the observer’s position in time implies that no travel to the past means no travel to the future–except for the ordinary kind where in just 60 seconds we can venture one minute into the future.

    • I think it’s because the “future”, or “changes in the motions of particles”, hasn’t/haven’t happened yet. The article seems to discuss a history of particle actions and the interaction between a past occurrence and one that has just occurred.

  10. Einstein theories relativity dont have a valid prove. Time traveling can be possible. If we can made a telepotation device that send the energy from one place to another within micro seconds. we know that now it is possible to send energy through wifi i which we need to transmit the energy from one source and then we place the reciever at the other end to recieve that energy and make use of them. In upcoming days time traveling must be possible, but by doing that we create two or more then two parallel paths of time 1> the original one 2> the one we created. and these two parallel paths never coincident on each other.
    ex:- suppose i kill my father in past then how can be i am in future. maybe the answer of this when i come back to future is i have no father or people think i’m alien but that’s not true.

  11. Travel to the past is predicated on the notion that somewhen the past still exists and there is absolutely no evidence for this. Matter and energy are in motion, as far as we have ever tested, they only exist NOW and time is a measurement of changing relationships amongst these entities using some of these same entities that are cyclical in nature as the means of measure. The notion of a block universe where all moments exist like frames on a film strip fails in the simplest way, it cannot explain what is moving. A hyper-dimensional being looking at a block universe could find nothing in motion, so how can we who are supposedly embedded in this physical theoretical amber do so?

  12. Time travel is merely a thought, if time travel was possible you could just make the decision for you or future generations of your family should feel compelled to make a time traveling machine….. So think about it…. Keep thinking. Poof nobody showed up huh?? So time travel is not possible or so inherently out of our reach that will never happen. You all are idiots and should kill yourselves including whatever bonehead scientists and physicists who sought monetary gain by completing this study.

  13. Not only is time an illusion, the entire material world is. Therefore, the illusion of time ‘travel’ is possible, that is, one could move back or forward within the illusion, albeit, there is only the eternal NOW, in actuality. Like a dream/movie, it can be wound forward or backward. Since the illusion is dependent on the perceiver, and his level of consciousness, a higher state of consciousness is capable of escaping (transcending) the illusion of time. The ‘travel’ in time would only be perceived by the less conscious, the traveler having gone nowhere at all. Relativity of Consciousness, I’d call it.

  14. Very interesting information, although after reading through some of the comments I started to lose sight of what the article was actually about. I would like to see people getting on the same level about communication and scientific breakthroughs. Not only does it bother me that people continue to ridicule and deny facts and theories, but they do it on a personal level. Very intelligent people are pursuing this field and searching to find out more about this universe on the visible and invisible spectrums, these people deserve respect. They’re doing this in hopes that people and “times” will change, or agree that we only exist fractionally on the current plane, however you want to look at it; but at least love and respect your neighbor. Maybe someday we will be able to live as our other entity before death and travel to distant worlds, pasts, and futures and hopefully learn something constructive to better mankind. So don’t criticize another man because he doesn’t think the same way as you or society, applaud him for having a different perspective and the drive to follow through with his theories amongst all of the criticism.

  15. at last humans got to know that ..they are the gods ..they build the matter ,.and the creater of the universe is humans ..
    this is paradox …
    i think humans are the gods ..
    that will one day discover that they are the one who created everrything ..even big bang