Hong Kong scientists claim to have proved that a single photon cannot travel faster than the speed of light in a vacuum, making time travel seemingly impossible.
These findings are consistent with Einstein's claim that the speed of light is the "traffic law of the universe" or, otherwise put, that nothing can travel faster than light. Of course, humanity's dream of time travel has long relied on the hope that Einstein was wrong. We got a glimmer of hope back in 1999 when scientists found superluminal (faster-than-light) propagation of optical pulses in some specific medium, the team said. Unfortunately, this was later revealed to be a visual effect, and the photons involved couldn't actually transmit information.
Since then, there has been a debate surrounding whether or not a single photon might actually be able to travel faster than the speed of light. This experiment, conducted by a team at the Hong Kong University of Science and Technology and led by Professor Shengwang Du, measured the ultimate speed of a photon using controllable waveforms. An explanation, from the press release:
"HKUST's team used a demonstration which required not only producing single photons, but separating the optical precursor, which is the wave-like propagation at the front of an optical pulse, from the rest of the photon wave packet. To do so, Prof Du's team generated a pair of photons, and then passed one of them through a group of laser-cooled rubidium atoms with an effect called electromagnetically induced transparency (EIT). For the first time, they successfully observed optical precursors of a single photon.
The team found that, as the fastest part of a single photon, the precursor wave front always travels at the speed of light in vacuum. The main wave packet of the single photon travels no faster than the speed of light in vacuum in any dispersive medium, and can be delayed up to 500 nanoseconds in a slow light medium. Even in a superluminal medium where the group velocity (of an optical pulse peak) is faster than the speed of light in vacuum, the main part of the single photon has no possibility to travel faster than its precursor."
What that means for us: probably no time travel. Du says their results "confirm the upper bound on how fast information travels with light. 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." That indicates, in turn, that time travel is not possible, and that decades of beloved science fiction may not be entirely based on fact.
Forgive me if I'm wrong, but surely "the speed of light is the speed of light" shouldn't exactly be shocking news...
Light doesn't travel faaster than light?!?!?
Oh my god! Now that's something!
yah, i was thinking the same thing, didn't even realize this was being debated, cool stuff regardless
Is it just me or do they seem to be jumping to conclusions? Sure, they may have proven that faster than light travel is impossible, but how does that prove time travel is also not possible? Have they considered there might be some other way of traveling through time that does not involve faster than light travel?
I remain skeptical on principle. I've always been taught that there are two definitions to the speed of light. One definition was the actual velocity of photons in a vaccuum, "c". The other definition is the theoretical maximum velocity in the universe, which is more of a metaphysical concept than a value.
The second definition has plenty of relatvaistic implications but I've always understood that the concept was flexible based on what we observe and could be changed based off experiments done in the future. It seems to me, by the way the article is worded, that the scientists reconfirmed the value of "c" and did not change our understanding of the theoretical maximum.
Also, doesn't that only mean that they weren't able to make the photon go faster than the speed of light? Maybe there's still some way of doing it...
I thought China put a stop to anything time travel related. Looks like someone broke the law.
This new experiments don't answer some of the spooky aspects of quantum physics, entanglement -- Einstein himself called it spooky. In 2008 entangled photons communications has been clocked at 10,000 times the speed of light.
Quantum weirdness wins again: Entanglement clocks in at 10,000+ times faster than light
Agreed - I mean, when was the last time you heard anyone talk about time travel via FTL in space? Modern science fiction, as well as modern physicists, continue to explore the concept through wormhole travel, bending space/time so that you don't have to travel through the vacuum of space. I don't think this author actually reads science fiction.
Ron, quantum entanglement doesn't speak to time travel or even FTL travel - merely FTL communication.
lmbo @ joey
Ah humanity! You have so much to learn. We know that basically everything is some form of electro-magnetic radiation. Everything from light to radio waves. We also know that "spooky action at a distance" works, somehow. Its also known as quantum entanglement and regardless the distance paired atoms will mimic each other. This either suggests (1) the existence of super-luminal radiation OR (2) the atoms are in some way adjacent and instantly exchanging energy as in a Newton's Cradle. In this case though, our ideas of "distance" and therefore "motion" would need a serious rethink.
Either way, it shatters the concept of "nothing faster than light." And if we can figure out which of those two cases is true, we will own the stars my dear Horatio.
Nobody knows exactly how/why quantum entanglement works. But I suspect it has something to do with negating the effects of "time." If true, we might learn how to apply this effect to ship and viola, FTL drives.
Remember, no one will ever fly in a heavier-than-air craft. No one will ever travel faster than the speed of sound. No one will ever fly in outer space. No one will ever set foot on the Moon.
Just keep telling the human race what it cannot do, and it will keep on doing it.
even if quantum entanglement can't be used to make faster than light propulsion, there is still an interesting consequence to time.
we can agree that time is running forward correct? for the sake of argument let's just say, yes, time is moving forward.
so how can we know when something is running backwards in time if we are running forwards? it would blink into existence for less than an instant and then disappear just as quickly.
or if we are trying to move something back in time then wouldn't it seem to just sit there? even though it's technically moving back in time? because once it goes forward in time again then it's making the same trip it did the first time.
this doesn't disprove time travel, and it doesn't disprove faster than light propulsion. this just kills the idea of doing it with light as the main power. and that's at best.
to mars or bust!
ftl travel will be achieved eventually. scientist also used to claim earth was the center of the universe and that the sun was guy in a chariot. saying it cant be done simply mean you've given up trying. 200 years ago man road horses, now we have satellites and space stations. imagine what the next 1000 years will see!
tap your watch and step into a new dimension and walk out onto another planet on the other side of the galaxy. fantasy yes....for now
I bet " Srinivasa Ramanujan " would have a different opinion about time travel!
I get the feeling that any time traveling humanity might do in the distant future would have less to do with the speed of light and more with the manipulation of spacetime itself. Maybe if you could find a way to turn spacetime back on itself or something, you'd be able to make time run backwards... or something like that. Granted, that's just a random idea that no basis whatsoever in reality, though it would still be cool if we could fold spacetime like a piece of fabric. I would think a technology like that would allow us to take shortcuts through spacetime, making it more useful for interstellar or even intergalactic travel than time travel. Oh well, maybe if science finds a way to make us immortal before I die of old age, I'll live to see that day. :P
A hem! Research this name " Srinivasa Ramanujan ". Absolute brilliant thinker!
There is an interesting time traveling phenomenon called the doppelganger in which the future self returns to the present. According to the eyewitnesses, of whom I am one also, there is a time difference of just less than 15 minutes which I will call 875.195556 seconds.
The future self moves out of the time line at pi/2, goes back in time with another two right angles for a total angle of 3pi/2. There has to be the tetrahedron angle of sin(19.47122063) which is a factor of 1/3. So the factor is
1/3 * 3pi/2= pi/2.
Because the geometry is logarithmic, the value we are looking for is the factor times the time interval times the speed of light in this dimension or
ln(pi/2 * 875.1957556 s * 299792458 m/s * 1/m) =
Thus e^-26.74463127) = 2.426354299^-12 meters
which is the electron wavelength.
In my case, a woman who was dressed in purple, a Catholic tradition on Good Friday for the sorrow of Jesus, was at a candle-light procession several miles away at 6:30 PM. About 15 minutes later, she had to sit down on a park bench due to an extreme headache.
I went to the restaurant at 7:00 PM to check on our reservation for 7:30 PM. The waitress surprised me by saying that the woman was just there at the restaurant and had spoken to her. I told her that was impossible because she was in the procession with a purple blouse.
When I returned at 7:30, the woman came in dressed in a red dress.
Also, around this time, a man, who was at home studying for a medical exam, was seen at the casino playing the Volcano machine.
So time travel is possible, as evidenced by the Billy Meier photographs of the dinosaurs. I also know that a glitch in the electronics of the Pleiadian Beamship sent two crews back in time. Upon rescuing them, the crew appeared moving very slowly in a time dilation event.
So when scientists make these declarations that time travel is impossible, we know better. We have the triple toroidal waveguide that produces a linear gear tooth time wave, the time warp generator where plants are grow fast compared to the control, the germination of a seed into leaves while held in the hand snd other examples.
SolusCado yea but:
So the quandary of what is information which two entangled particle transmit from one photon to the other over 10,000 times the speed of light. I am communication with you at a much slower speed through the invent of the internet my binary numbers talking to your binary numbers right now. With a 3D printer I can take information at my end and communicate to you and make a 3D plastic object from my corner of the Earth to yours, if you had a 3D printer, just by communication with your 3D printer. Of course it will take time to reassemble that information into a 3D object but if your thousands of light years away then that time is infinitesimally small compared to the time it would take to travel there, even if you were traveling close to light speeds. In other words I can take information from a AutoCad object in 3D space at my place and make a 3D object with mass at your place.
A Quantum computer, scientist have been working on for the last ten years, with entangled photons should be able to take the communication from two entangled connections and do the same thing over 10,000 times faster than the speed of light. As a result a clone of an object sent though a quantum entangled communication link 10,000 times the speed of light can be reassembled with mass at great distances -- it is though mass is traveling over 10,000 times the speed of light???
I love that you all beat me to the quantum entanglement subject. My thoughts exactly, love the idea of using it with a 3d printer rlb2. In theory we could build much more advanced 3d printers, such as the star trek "replicators" and print ourselves out on the other end :) ...lets just hope bad guys don't use this haha *shudders at agent smith flashback from matrix*
Beam me up Scotty. 1134 just think what an advanced Organic 3D printer can do, taking the organic soup and first make stem cells then from there assembling a human being thousands of light years away, just from the transmission of information through space.
There is no need to transmit the information when the actual person can be teleported to the location through the subspace tetrahedral logarithmic manifold that connects all regions of space-time.
Communication in real time is easily accomplished out to 80,000 light years through this manifold.
I don't believe in Chinese researchers because they tend to bend physics to their Buddhist beliefs. We know that the speed of light in other dimensions is as low as 1 m/s. Thus there are other hyperspace co-dimensions that have a faster speed of light.
The Grey aliens liken the situation to a dam filled with water. If you are submerged in the middle, then the speed of light is faster or slower than yours. So there has to be a faster speed of light in a higher co-dimension which I don't think these researchers considered.
It doesn't matter though because spacecraft teleport from one location to another in less time that it takes to walk across the street. So our light speed is not a factor in the teleportation.
Recently the NSA confiscated a book about ancient Greek gods which apparently showed a picture of the Parthenon as it was in ancient times, not the rubble as it is now. The picture shows that time travel is possible.
I hate to use the word but the"mathematics"of the Theory of Relativity predicts not the speed of light but the maximum universal speed of a "massless particle", of which the photon is one of. In the formula E=mc^2, the c is a convenient contraction sort of like the formula for a right triangle c^2 = a^2 + b^2 is a convenient contraction of the Law of Sines.
I just thought of a question I would really like answered.
Why does light travel slower through some mediums? Does it lose energy while in there? Does it get the energy back once it returns to a high speed medium? And if it gets the energy back, how the fuck?
There is information without inetia and therefore not limited by the speed of light such as is entanglement. As soon as we can confirm what causes gravity we will know what limits the speed of light and therefore should be able to manipulate it. Whatever creates inertia also causes gravity. Maybe someday soon we will find our god particle.
Till then we can only measure with what we can see; electromagnetic radiation. WHICH IS ALSO AFFECTED BY INERTIA. Seems like a tangled web we weave. By the way, time is not a fact just a concept which cannot be observed.
We can only measure changes in relative existence in relationship to a standard. This standard is always based on some photonic phenomena or decay. You measure relativity with this physical property you will always set this as the limit of existence which in actuality has no limits. It is very hard to quantify things we cannot measure. Presently we can only measure phenomena that has inertia. If we someday think outside the box we may see things we never imagined and understand the actual fabric of what we call existence. Scientists must get into the non physical part of the universe to truly understand how it manipulates the physical. One set of observations is a very arrogant way to profess as hard fact that the speed of light is the ultimate rate at which relative existence can change.
Light doesn't travel at a lower speed through a medium. You need to take a page from Feynman.
He said that a photon does not reflect off a surface at equal angles. Actually, the photon is absorbed by the medium and then emitted again. The emitted photons are in phase and reinforce each other if the angles are the same. Thus it appears as though the photon bounces off the surface at equal angles. Many photon negatively reinforce and hence cancel in other directions.
So the explanation is that the photon is absorbed and emitted by the medium which creates a delay in the transmission, but the photon still travels at the speed of light in the vacuum between the atoms.
@frong...i was wondereing when someone would mention manipulating space/time, this is how the future will cheat the speed of light by creating shortcuts to travel vast distances, it appears that the speed of light is a constant, all modern physics proves this, Einstien was convinced of this even though spooky actions at the quantum level unsettled him, entanglement could just be connections we don't understand, like a very long train playing tug of war that we cannot see, just as we can't see dark energy but it appears to exist, cheers
@ Johnstclair. Just a guess, schizophrenia? If you say no then i think you need to see a doctor. Lol. Could you post your occupation? Just curious. Need to know where to get a job if I lose it.(my mind). What exactly would you consider your area of expertise? Obviously my major is much too serious. Mech eng tech. I will say you put a hell of a lot of effort into your comments.
please don't feed the trolls, i just skip past his comments and bubbanuts