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Electromagnetic Signals Exceeding Light Speed?

intaglio

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This article published by UPS worries me. The report is rendered difficult to believe by the erroneous description of superluminal light transmission (what they are discribing is slowing down of light). So is this report believable?

Faster-than-light electric pulses
Published 1/21/2002 5:58 PM


MONCTON, New Brunswick, Jan. 21 (UPI) -- Canadian scientists have sent electric pulses over long ranges at speeds faster than light for the first time.

The researchers believe their findings may one day help greatly increase computer and telecommunications speeds.

"The most important part of the finding is that it is the first time something -- anything -- was seen traveling over such distances at superluminal speeds," said lead researcher Alain Hache, a physicist at the University of Moncton in Canada.

The investigators stress it is not theoretically possible to send useful data at superluminal or faster than light velocities. However, they believe their results may help speed up electronics by more than half.

"Right now, the signal velocity in any wire -- a wire inside a computer chip, a phone wire -- is only a fraction of the speed of light," Hache said in an interview with United Press International. "One might one day accelerate those pulses up to the speed of light."

The speed of light is theoretically the fastest possible. First measured in 1675 by analyzing sunlight reflected off the moons of Jupiter, light speed is roughly 670 million miles per hour in vacuum -- fast enough to go around the Earth in about a tenth of a second.

The theory of relativity proposed by Einstein suggests exceeding the light barrier would lead to impossible results, such as cause after effect -- time travel. Scientists, however, have experimentally broken this speed limit for the past two decades, transmitting light pulses that move at superluminal speeds.

The key to understanding this apparently impossible phenomenon is to visualize a pulse of light as a group of waves all intermingled with each other. This group pulse rises and falls in energy over space, with a peak of strength in the middle.

Materials that absorb or disperse light can force the different waves in a group pulse to shift. The waves making up the rear of this pulse can be made to interfere with each other to drive the pulse's peak forward in space, resulting in the pulse traveling at superluminal speed.

Scientists were previously able to generate superluminal pulses of light over very short distances of only a few feet at most using very complex equipment. The research team managed to generate electric pulses that moved faster than light over a simple wire for the first time -- signals that moved at three times the speed of light over more than 500 feet.

The researchers connected a series of off-the-shelf store-bought wires together, each with different electrical resistance levels. This created reflections in the signals for the superluminal effect.

"The same laws that apply for light waves also apply for electrical waves," Hache explained.

Do not expect superluminal starships or time machines anytime soon, however. Since the energy that makes up the group pulse does not actually travel faster than light, the theory of relativity remains unbroken. A signal also gets weaker and more distorted the faster it goes, so it is theoretically impossible to send useful information at superluminal speeds.

However, the researchers do hope to use their reflection technique to help increase the speed of electrical signals traveling down existing telecommunication cables.

"At the moment, plain coaxial cables allow a velocity of about two-thirds the speed of light," Hache said. "By texturing the cable... we might bring that limit closer to light speed. There would be a lot of applications for that, like in computers when you send a bit from A to B."

Superluminal physics expert Mohammad Mojahedi, an electrical engineer at the University of Toronto, said this work may help move faster-than-light phenomena "from the physics aspect to the engineering aspects, to make faster devices."

(Reported by Charles Choi in New York.)
 
Hello Intaglio.

I too find the article a little lacking. I am however reminded of research from the late eighties which featured in Electronics Today which described the transmission of electrical signal "Wavefronts" ( Not Standing or Traveling waves)traversing straight copper conductors at speeds much greater that Lightspeed and I mean lightspeed in freespace. Unfortunately I do not have the article here with me but I shall try and locate it. Interestingly the transmission speed seemed to vary with the direction of the conductor. but we all "Know" there is nothing travelling faster than light don't we?
 
I guess the reporter hasn't got his GCSE in Physics yet ;)

It's a common mis-conception that the speed of light is always constant, but Einstein's theory really just says that c is constant in a vacuum, all other things being equal. At least, that's how I understood it but I may well be talking out of my posterier here! Where's a bona-fide physicist when you need one, eh?

Just a thought, but if a small amount of knowledge is a dangerous thing, then is a small amount of danger a knowledgeable thing?

J.
 
Yes, Mejane, the speed of light in a vacuum is supposed to be constant. But Einstein never proved this, he merely took it as a basic assumption, and then showed that this idea was not incompatible with the principle of relativity (don't ask, I haven't time!).

So the speed of light is always measured as the same value, irrespective of relative movements between observers and light sources, because this is built into the foundations of the theory.

But as I get older, I wonder more and more whether old Albert didn't pull off a scam there. After all, there were already other theories to explain the observed results - the Fitzgerald-Lorentz contraction of length, and an analogous effect on time - which did not require the speed of light to be constant.

But Einstein's view was deemed to be simpler (by that dreaded Occam's Razor principle) and won the day. It doesn't mean the universe IS that way, just that our tiny minds can handle it better if we think of it that way.

I still think it's a cop-out, taking something you can't explain or understand, and making it the cornerstone of your theory! I reckon Albert is having a right good chuckle over on the other side...
 
As far as I understood the article, it did talk about signals moving faster than light in a vacuum. But it is badly written so I don't know.

As for Einstein, it is hard to show wether or not something can move faster than light. Except if you found something that did. But have you read his theories? I mean Einstein also talks about contraction in lenght and time. And the effects he predicted thereby has been shown to be true.
 
Yes, I have studied Einstein. His length contraction, etc, arises out of the maths of assuming the speed of light is constant.

The early alternative theories suggested that objects moving through the ether (the hypothetical medium through which light travels) would contract in the direction of their motion, rather as if a boat was compressed along its length by the pressure of its bow-wave.

Mathematically the two theories are equivalent - Einstein's, by ignoring the ether, no longer allows us to understand how the electro-magnetic waves that make light (and radio, gamma rays, etc) actually travel.

Waves on the sea move in water, sound waves move in air, but e/m waves move in... what? Einstein didn't know, so didn't say - he ignored the question. He gave no physical model for the transmission of light.
 
But since the ether was never shown to exist, saying light is waves in the ether doesn't make it much better.

I think the lengt contraction through the ether was disproved somehow, but I can't remember.

What is interesting is how people now talk about ZPE as being a new ether.

If Einstein makes some math equations based on a constant speed of light, and is then able to show surprising things that are later verified, as the slowing down of time, seems to show me he was right.
 
I was just pointing out that science is much less consistant than many people think. It is a cluster of different theories, all of which are more or less 'correct' in their own little domain but which don't sit comfortably with each other. One of the biggest things in physics at present is to reconcile Quantum Theory with General Relativity, which are fundamentally different in their world-view.

So large chunks of science accept that e/m radiation is a wave motion, and many practical uses depend on this idea, but we still have no medium for it to 'wave' in. As you say, X, maybe a better understanding of ZPE will fill the gap.

Einstein certainly got many things right, which is how he got the 'genius' reputation, but it's important when watching the conjuror to notice what he really does as opposed to what he appears to do. Einstein kicked away the physical medium that transmits light while everyone was admiring the pretty silk scarfs he was pulling out of the hat!

To paraphrase Fort: "I see nothing in Science that is more than the proper thing to wear, for a while."

Everyone thought Newton had answered everything at one time, but science moves on - one day, no doubt, we'll see Einstein's work in a more complete context.
 
Einstein said you cannot travel AT the speed of light.

Light can be slowed down in a supercool environment. I believe the record low is 38mph--that was in the news (Reuters) at some point in the last couple of years. I can't remember the scientist's name, but I will try to look it up.
I also read more recently (within the last 8 months, I think, and also on Reuters) that some radio astronomers had proof that not all frequencies of light travel at the same speed. I'll try to find that one, too. I think there was a link to it from the FT homepage, even.

I agree it is a poorly written article.
 
To ask "what medium does light travel through?" is to only consider part of the picture. Light may also be thought of as a particle, i.e. a photon.

An electron can behave as if it is wave-like. We could equally ask "what is the medium that an electron travels through?"
 
Fortis said:
An electron can behave as if it is wave-like. We could equally ask "what is the medium that an electron travels through?"
Quite right. A question neglected by modern physics at present. We know how waves travel though solids, liquids, gases and plasmas, but not through vacuum... An odd state of affairs.
 
I think we're getting confused about the meaning of "wave" here. In this context it means that light (EM radiation) is a continuous waveform - i.e. it cannot be broken down into discrete particles. It doesn't need anything to travel through, anymore than the mathematical concept of a sinewave needs a medium.

Unfortunately for old Alf, light does appear to be composed of a stream of discrete particles (photons) in some circumstances. Further investigation seemed to show that light could behave as both a wave (when it travels) and as a particle (when interacting with matter). The 'truth' in my own (very humble) opinion is that we don't yet understand the real nature of light, but that doesn't mean that it is unknowable.

Getting back to the speed of light... there was an article in New Scientist (I think) some time ago about how the speed calculated by various experimenters over the last 50 years or so had an alarming tendency to fluctuate. This topic is also covered by Dr Rupert Sheldrake in "7 Experiments to Change the World". The solution: set an "official" speed!

J.
 
Hello.

Sorry I made a mistake in my last posting on this thread that experimentation with faster than light signals (2 seemingly different ones no less), in wires, was in the Magazine Electronics and Wireless World Dec 1988 edition I managed to dig a copy up and it should be within the ability of a high school science department to replicate. (give or take a decent Oscilloscope). If anyone fancies having a go I can post the details.
 
My intention was to suggest that just as we don't worry about what medium electrons travel through, neither should we necessarily be too concerned about what medium light (i.e. photons) travels through. :)
 
But it's often people worying about the discrepancies in current theories that leads to the next breakthrough in understanding.

I suppose it depends on whether you're a practical, technologist type, just interested in getting something to work, or whether you're into theory, and like to undestand how everything links together (if it does, that is...!).
 
We tend to think that everything will one day be explainable, that it's just a matter of time before the grand unified theory, general relativity, special relativity and quantum theory are brought together. However it seems to me that this is a fundamental mistake. If the edges of these theories fail to meet only forcing them into a new overall theory that has many exceptions will follow. I think it much more likely that something like superstring theory will prevail, ie. a whole new model of the universe which can explain such discrepancies as dark matter, the miscalculation of the age of the universe, black holes and so on.

Star trek's got a lot to answer for ;)
 
Wave/particle duality is really rather tricky.

Firstly whether photons are waves or particles depends upon what you want them to be at the time you study them. Look for a wave and it will be, look for a particle and it is. You can even set up an experiment that can examine both results and you will get either wave or particle but not both. :confused:

Secondly remember these rules apply to all sub-atomic particles and atoms.

Supraluminal light transmission depends on a property called tunnelling. When a photon hits something that is a complete barrier to it's transmission there is a small probability that it will tunnel through the obstruction. It will appear on the other side without having passed through the intervening space. Traversing no space takes no time, the collapse of the wave function on one side of the material will be matched by the simultaneous appearance of the wave function on the other. Throw enough photons at the first of a series of such barriers and you end up with some light going from one end of an experiment to the other faster than light traversing the same experiment without barriers. :cross eye (Correct me if I'm wrong rynner but I think Big E denied that the term simultanaity had any meaning.)

The problem gets more complicated when you factor in rest mass. Electrons have it and as such, in vacuum, can never travel at the speed of light. They also are far less likely to tunnel. What this report says is that usefull quantities of information can be transmitted with electrons from one postion to another faster than light could so. :madeyes:
 
Big E said that simultaneity is - well - Relative! For instance, one observer might see two simultaneous lightning strikes at different places, but another observer, in a different place and/or a different state of motion, would probably see one strike occur before the other.

But cause and effect are still in the correct order in E's Relativity - no observer, whatever his state of motion, could ever see the target hit before the gun is fired.
 
dot23 said:
Star trek's got a lot to answer for ;)

I am taking a course in Museum Education, and I just read about a front-end study for a science museum. The museum thought that their visitors' misconceptions about physics were due to folklore, but the study showed they were mostly due to Star Trek.
 
vindicated - at last! It alawys annoyed me, all this next gen pseudo physics, why couldn't they just leave it well alone - oh well that's what you get out of the US education system I expect.

I'll jst get my coat before all the yanks get on my back

:)
 
dot23 said:
I'll jst get my coat before all the yanks get on my back

:)

Yeah, you get that red coat of yours and RUN, buddy!

I'm sorry to tell you that I have attended university in the US and in England, and I am not impressed with either education system. They both have their faults.

Anyway, the museum was in Canada.
 
I have this nasty feeling that there was another survey that ST was the biggest factor influencing students to look a science for a career
 
They also did a survey at NASA asking how many of the people thought they wouldn't have been there if it wasn't for Star Trek. It was the majority.
 
maybe all that pseudo science has a use after all - it's funny to think that ST has influenced the sciences in such a way . Still it's no different from the 50s and 60s when Scifi pulp magazines also held sway in the scientific community - my father was an avid fan of Astounding etc and this lead to him studying science at University.

afebk - what did you find disappointing ijn both systems - it'd be interesting to hear from someone who's seen both sides of the argument about higher education. An American university lecturer I met recently agreed with me that the sponsorship system (especially with sports) had lead the system into disrepute and should be scaled down if not removed - do you agree?
 
Just going to make a couple of points, then I'm going to get out of the firing line :)
1) Information CAN travel at speeds greater than c. See my award winning article for the Daily Telegraph, 1995, and the research conducted in Germany that sent Moazart across the lab at 4.7 times the speed of light in a vacuum.
2) c applies to light in a vacuum - photons can travel at a greater velocity than the local speed of light in their current medium. The cone of radiation given out when they do so is called Cerenkov Radiation, and can be studied and tested to your hearts desire.
3) Relativity (General or Special) does not prevent the transmission of information faster than c. All it prevents is particles with mass travelling at c, and massless particles travelling at more than c. Nowhere does it state that particles of negative mass cannot travel faster than c. And as for particles with negative mass existing, we need only look at the non-existence of the Neutrino (c. 1920) and the non-existence of the Electron (c. 1900) to show that what hasn't been imagined does not necessarily not exist!
 
I ain't arguing Anton but Einstein does say that anything that travels faster than light is going backwards in time. The idea that no useable information could be sent was a gloss put on the original theory to stop nasty things like (blast, my brains gone dead I've forgotten the word; it'll come to me later) killing your own parents before your conception.

This is one of the areas where Relativity is weaker than quantum theory. In fact Relativity is starting to show holes on the macroscopic not just the microscopic scale. Quantum theory is still struggling with gravity - that remains it's weakness. If you look at these two combatants it looks increasingly like the state of physics in the late 19th C where existing theories were showing faults and a new synthesis was eventually needed.
 
Okay, I'm going to put the oxygen mask on and dive in again...

I don't think you'll find anyone arguing that relativity (even the general and special theories don't quite mesh together), quantum mechanics, superstrings etc are the ultimate explanation to the nature of the universe - that is why they're called theories .

As for science education... I can't speak for the American system, but I was taught (in the early 1970s) that atoms were the smallest possible particle! Mind you, the same teacher also said that electrons are green (hence the display on the oscilloscope) and that north is always in front of you. ;)

Jane (lost again - compass is broken).
 
mejane said:
As for science education... I can't speak for the American system, but I was taught (in the early 1970s) that atoms were the smallest possible particle! Mind you, the same teacher also said that electrons are green (hence the display on the oscilloscope) and that north is always in front of you. ;)

Jane (lost again - compass is broken).

I can understand the atom thing. (In the original atomic theory of Democritus atoms were defined as being the smallest undivisible parts of "stuff". I guess that according to this what we currently refer to as atoms are not atoms.) It probably depends on what level the subject was taught at. It was relatively late on that I was taught that electrons didn't orbit around a nucleus in nice circular orbits, but that they were best described as being smeared out into wonderfully shaped orbitals.

As for the the green electrons, teachers can be very strange at times when explaining stuff that they don't understand. When I was at primary school, I was given a slide rule by a relative. I took this strange object to school and asked a teacher what it was for. She informed me that it was for measuring distances very accurately.:rolleyes:
 
mejane said:
....but I was taught (in the early 1970s) that atoms were the smallest possible particle! ......

Me, too, likewise.

Then we learned about neutrons, protons and electrons, but that they only existed together, i.e. as atoms.

All these new-fangled thingies - hadrons, quarks, mesons, whatever - were either theoretical, or maybe seen occasionaly as tracks after high-energy collisions, and way beyond the scope of secondary school physics.

And now they're not. Oh dear, am I getting old? :(

(BTW, one third of all electrons are green, one third blue, and one third red - that's why we have RGB monitors!) :confused:
 
I remember (ah! the smell of madelaines) when I was about 7 I broke my pencil and being a lazy child couldnt be bothered to go to the pencil sharpener so I was chewing it sharp. The teacher came up behind me and told me not to do that because I'd "get lead poisoning". When I turned round and told her it was not lead in the pencil but graphite and clay she became quite annoyed and gave me *lines* for talking back. I think it was later in the same year when they said that Mary was a virgin and I popped up with "but she couldn't have been, she got pregnant and had a child".

I must have been the most obnoxious brat!
 
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