Faster than light propagation demonstrated

Link to the story, please?

I found this story, too:

http://partners.nytimes.com/library/national/science/053000sci-physics-light.html

oops, the link didn't work, I didn't notice that. Sorry. here it is:

http://www.santafenewmexican.com/LANL_scientist_makes_radio_waves_travel_faster_than_light

Thank you for the link. I've read the article.

Quite interesting but more proof will be needed before acceptance.

Thank goodness, there will be further research into the phenomenon as indicated in the article.

Best regards,

Ethobil

"If you take a laser and shine it on the moon and swing it rather gently, for example, the spot on the moon travels faster than the speed of light," Singleton said.

What's that all about? Surely nothing is actually travelling faster than c - there's no transfer of matter or energy between the points being illuminated.

There are all sorts of "tricks" to make light appear to travel faster than c, but the crux is that no information has ever been indisputably transmitted faster than light in a vacuum.

The 300c that is reported in this experiment is a "wave" traveling backwards to meet the peak of the forward wave as it enters the apparatus - what use can it possibly have? These sort of demonstrations are around for a couple of years already, but none has produced super-luminal data transfer yet.

Jorrie

Hi Jorrie, I'm just wondering if the "backward wave" in the example given in Rorschach's link to the work of Dr. Lijun Wang might be phase modulated by injecting light from another phase tuned laser similar to the beat frequency oscillator in radio recievers.

The article quotes Dr. Wang as saying "our light pulses can indeed be made to travel faster than c. This is a special property of light itself which is different from a familiar object like a brick" since light is a wave with no mass.

Note the author left the remainder of this statement outside of the quotation marks which makes me wonder if this is an editorial typo or does Dr Wang really reject the photon theory of light?

Certainly John Singleton's work is unique and seems to hold possibilities for similar modulation schemes such as phase modulation, whether by injection into the prime carrier or by hetrodyning.

Eh, maybe not there Taejonkwando. Remember that light is both a wave and a particle, but that particle (a photon) has no mass. Since it has no mass, it is not matter in the canonical of the standard model.

Hi taejonkwando, I'm not even sure that that "backward wave" traveling at ~300c is even real, or perhaps just an artifact of the measuring equipment! In any case, it seems to be a 'virtual wave' to me, so I've got no clue how one would modulate it...

Jorrie

Jorrie, greetings; I've not been around here very long, so don't know if this has been a subject of discussion, but what about the (AFAIK controversial) concept of baryons vs tachyons? The baryons being photons and slower that we are familiar with because they are observable, and none can travel faster than c. The tachyons being similar (supposedly) but cannot travel slower than c, therefore not directly observable by us, hence unfamiliar. It seems relevant in this context. Any thoughts on this?

Hi EnviroMan. You wrote: "The baryons being photons and slower that we are familiar with because they are observable, and none can travel faster than c."

Baryons are not photons, they're ordinary particles like electrons, etc. None can reach a speed of relative to any inertial frame. Tachyons are hypothetical particles coming out of the relativistic equations, that may or may not exist. It is not necessarily so that we will not be able to detect them because they move faster than light. If they exist, they must still be able to carry energy and we may be able to built a tachyon transmitter and detector.

However, Wikipedia says: "According to the contemporary and widely accepted understanding of the concept of a particle, tachyon particles are too unstable to be treated as existing.[4]. By that theory, faster than light information transmission and causality violation with tachyons are impossible on both grounds: they are non-existent in the first place (by tachyon condensation)[4] and even if they existed (by Feinberg's analysis[3]) they wouldn't be able to transmit information (also by Feinberg's analysis[3]).However the debate and scientific speculation over the existence of tachyon is still open. [5]"

Jorrie

Hello Rorschach

Nothing can exceed the fastest method of knowing it is there, or are able to measure.

Because light is the fastest thing we know of, nothing can ever exceed the speed of light, because for the observer it does not exist.

Well understood by Einstein, and since misunderstood by so many, including well-meaning Physics Professors et al.

It was, after all, a Theory of Relativity = Relative to the observer.

Kind Regards....

In this case, I don't think it's the physics professor's fault. I think this is a case of poor reporting. It reads as if the journalist is trying to explain something he doesn't understand.

Im more interested in the ramifacations on science if this does prove to be true. I mean, the speed of light being the fastest obtainable speed has sort of been at the the crux of the last 60+ years worth of quantum and theoretical physics. I wonder what problems had solutions where velocity exceeded the speed of light, and therefore were subsequently rejected. I know there has been some discussion about the speed of light slowing down since the creation of the universe, and so I wonder what its original speed was, and how the current accepted speed and this scientists reported speed compare.

The speed of light is dependant on the medium of travel.

Will we get light to travel faster than light in a vacuum.? Probably. We now have negative refracting lenses why not faster than light in a vacuum mediums.

The applications will only be over the distance you can afford to use the medium. Except for war drones I can see no practical application now, until several orders of magnitude of faster than light. 1 AU = 7min, 2C 1AU = 3.5min...

Instantaneous communication is what is needed. Maybe some form of entanglement.

We are starting to understand light, but gravity and time we know very little. I think when we understand them FTL (faster than light) will be do able.

Brad

Food for thought...

If I recall correctly the influence or propagation of a magnetic field, how ever so slight over distance happens instantly. Therefor it's effect happens at speeds greater than c.

I'm certainly no physicist, but I thought that the photon was the particle carrier for the electromagnetic force. If that is the case, wouldn't magnetism (being an aspect of the electromagnetic force), be limited to the speed of a photon?

Rorschach, ... "I thought that the photon was the particle carrier for the electromagnetic force." You are mostly correct. If I remember my physics history, the photon was the AGREED upon carrier, but electromagnetic theory stated that EM is BOTH a particle and a wave. In other words some observed phenomenon said that light is a particle others say that it was a wave. There was at that point no actual agreement. If it is truly both then much of our knowledge of physics will have to be revised.

Dragon

Wasn't there a test, of sorts, that was done showing that in a certain liquid light (particle or beam?) could actually be slowed done? Faster than light? Sounds like good ol' Han and his "I know she doesn't look like much but she's got it where it counts. She'll make point five past light speed..." from Star Wars... Cheers

Google Bose-Einstein condensation tons of stuff.

Got to be Darth Vader's body guard for the StarTrek convention in Seattle before the first release of Star Wars. George Lucas gave us a 4hr. presentation on the making of Star Wars and hooked me on Hi-Tech. I have to thank Ray for that gig.

Brad

There's been agreement for a very long time that both photons and subatomic particles act like both wave and particles. And a whole lot of physics has been built on that concept for the last 80 years!

Where the heck were you guys?!

Dragonsfarm, see my #11...

Rorschach, Granted. Then that would mean that the wave could only travel as fast as the medium it was made of?

Dragon

Dragonsfarm, that would be my layman's understanding. BUT (and this is a big but), the propagation medium plays a role of course. Light moves at different speeds depending on the medium. Bose-Einstein condensates for example can be used to slow light down to a comfortable walking speed. But the speed of light in a vacuum used to be considered the upper limit.

My (probably severely flawed) understanding of what many of these people appear to have done is found a medium in which the speed is faster than it is in a vacuum. They appear to be doing this with metamaterials in which the refractive index is negative. Ok, I don't see where any fundamental laws have been violated with that (although the claim of 300 times c is frankly painful to contemplate). But this last one does not appear to make a mention of what medium it is in. That strikes me as fundamentally different from what has been done before. Either way, the idea that the speed of light in a vacuum is the upper limit appears to need revision.

BTW, the force that appears to be able to operate instantaneously across any distance is gravity. And until we understand how gravity works on a quantum level, that will remain a conundrum.

If I may interject...

"...the force that appears to be able to operate instantaneously across any distance is gravity..."

I've heard that stated, but AFAIK, 1) gravity is a property of mass, 2) we have not observed the creation/loss of a significant quantity of mass to be able to measure this, and 3) how would we? That part about 'any' distance is also bothersome. Go out far enough that we can't see what's happening from here (the observable universe may or not be infinite) and is mass being created/destroyed there? Is gravity increasing/decreasing due to this? More conundra, eh?

Dragonsfarm,

If I may answer for Jorrie (IMHO), gravity is the distortion of space and time caused by the existence of matter. In other words, matter, especially large clumps of it, like stars and galaxies, distort space and time which we see as gravity.

Your second question is the focal point point of the problem between Quantum Physics and Relativity. QP is looking for a particle that is used to transmit the gravitational force, while Relativity states it's simply the distortion in space/time caused by the existence of matter.

Hi vermin. "QP is looking for a particle that is used to transmit the gravitational force, while Relativity states it's simply the distortion in space/time caused by the existence of matter."

Another issue with the hypothetical graviton is that if it is the carrier of the gravitational "force", then it is not a gravitational wave! Gravitational waves are oscillations of the force, or more correctly, ripples in spacetime curvature. I suppose one can say that if gravitons carry the spacetime curvature, then any change in that curvature is also carried by them...

Jorrie

And that's exactly why quantum physicists and relativity physicists are ducked down behind logs and shooting at each other!!!

This "Graviton" of which you speak, would it not be the Higgs Boson? Is this not the reason why the LHC was built to begin with? To find the Higgs?

You talk of gravity being a wave and not a particle but have we not already settled that a photon is a particle and a wave? why should the Higgs be different?

Simply put, no. The Higgs boson has nothing to do with gavitons or gravity waves.

Where do you guys get this stuff!!!

Isn't the 'Iggs bosun a mediator (if that's the right term) of the forces among the various flavors, colors, shapes, etc. of quarks? Or am I mixing that up with the J? Been awhile since I contemplated these guys...

That is not my understanding at all. My understanding is that the Higgs is the mediator and "charge carrier" of mass.

Not that wikipedia is a reliable source to cite, but here is what they say on the matter (no pun intended)

http://en.wikipedia.org/wiki/Higgs_boson

It's implicit in Einstein's gravity wave theories that gravity, too, travels at the speed of light. All current attempts to create gravity-wave observatories are based on this.

Electric fields, magnetic fields, and even gravitational fields all propagate at the speed of light.

The thing I'm having a problem with here is that so much is being pulled out of a very poorly written article! It's immediately apparent that the journalist didn't explain anything about what the scientist is actually doing, other than siting a couple of the scientist's quotes.

• If you shine a laser on the moon and move the laser back-and-forth so that the spot of the laser travels across the face of the moon faster than the speed of light, there is no problem because light itself is not moving faster than c. Just the wave front is moving faster than light, which means you still can't send information any faster than c.
• There was also talk about when something moves faster than light, it causes a shock wave, like a sonic boom. This has been known for a long time. There are many materials through which the speed of light is slower than the speed at which certain subatomic particles can go through. The passage of these particles moving faster than the speed of light create shock waves which are observed as bursts of light known as Čerenkov radiation.

Other than these two references, the rest of the article was the journalist going "glub, glub." as he sank way over his own head. Where you guys are getting all this other stuff is beyond me!