College kids break the speed of light.

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Ok.. I thought it was still sor tof impossible to break the speed of light.
??!!

From New Scientist.com

Electric signals can be transmitted at least four times faster than the speed of light using only basic equipment that would be found in virtually any college science department.

Scientists have sent light signals at faster-than-light speeds over the distances of a few metres for the last two decades - but only with the aid of complicated, expensive equipment. Now student physicists at Middle Tennessee State University have broken that speed limit over distances of nearly 120 metres, using off-the-shelf equipment costing just $500.

Jeremy Munday and Bill Robertson made a 120-metre-long cable by alternating six- to eight-metre-long lengths of two different kinds of coaxial cable, each with a different electrical impedance. They hooked this hybrid cable up to two signal generators, one of which broadcast a fast wave, the other a slow one. The waves interfere with each other to produce electric pulses, which can be watched using an oscilloscope.

Any pulse, whether electrical, light or sound, can be imagined as a group of tiny intermingled waves. The energy of this "group pulse" rises and falls over space, with a peak in the middle. The different electrical resistances in the hybrid cable cause the waves in the pulse's rear to reflect off each other, accelerating the pulse's peak forward.

Four billion km/h
By using the oscilloscope to trace the pulse's strength and speed, the researchers confirmed they sent the signal's peak tunnelling through the cable at more than four billion kilometres per hour.

"It really is basement science," Robertson said. The apparatus is so simple that Robertson once assembled the setup from scratch in 40 minutes.

While the peak moves faster than light speed, the total energy of the pulse does not. This means Einstein's relativity is preserved, so do not expect super-fast starships or time machines anytime soon.

Signals also get weaker and more distorted the faster they go, so in theory no useful information can get transmitted at faster-than-light speeds, though Robertson hopes his students and others can now rigorously and cheaply test those ideas.

Physicist Alain Hache at the University of Moncton in Canada adds that it may be possible to use this reflection technique to boost electrical signal speeds in computers and telecommunications grids by more than 50 per cent.

Electrical signals usually travel at about two-thirds of light speed in wires. Hache says it may be possible to send unsable electrical signals to near light speed.

This seems... WAY to simple..

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whoa - waiting for some electrical engineers to put in their 2 cents.

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You and me both.
According to the recorded calculations, they broke the speed of light by 4 TIMES.

In thier own back yard.
And yet, when you break it down, you almost want to just fall backwards.. and say.. " fukn duh"!!
I do wonder how this is going to effect our technology. Actually.. i should say.. how QUICKLY it will effect our technology. It will make some waves.. but I wonder if the changes will happen soon enough were the common consumer can see it.

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I don't see how this can be translated into consumer goods that will be cost effective.

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No. you are right. It wont be.
I was just thinking ( in my scatterbrained way ) how would something like this could possibly trickle down on to the simple things we buy. But you are right.
The more I think about it, the less use I see for it .

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I'm still smarting from the successful cold fusion experiment performed at some college in Utah. Sadly, as it turned out, it only worked at some college in Utah.

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shewolf, Just because we can't think of any use for the faster speed of light, that doesn't negate the fact that some college students were able to accomplish this feat without expensive equipment. Research is the basis for the development of new technology, and we can't really know what is ahead for our future. I think it's great that you shared this info with us.

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cool

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Well, considering you have a supercomputer at your fingertips, I don't see why this cannot be commercialized if in fact true.

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I have a hard time believing this....

Measurement error, anyone?

Edit: Ah, re-read the article posted and found this:

Quote:

While the peak moves faster than light speed, the total energy of the pulse does not. This means Einstein's relativity is preserved, so do not expect super-fast starships or time machines anytime soon.

Signals also get weaker and more distorted the faster they go, so in theory no useful information can get transmitted at faster-than-light speeds

I've actually read about similar phenomena before.

You have a pulse that enters a gate:

Code:



    ..        ..        ..        ..        ..    

   .  .      .  .      .  .      .  .      .  .   

  .    .    .    .    .    .    .    .    .    .  

..      ....      ....      ....      ....      ..

And the pulse that leaves the gate looks like:

Code:



..        ..        ..        ..        ..    

. .       . .       . .       . .       . .       

.  .      .  .      .  .      .  .      .  .      

.   .......   .......   .......   .......   ......

Now if the equipment that detects the pulse only detects the peak then it looks like the pulse has sped up; in fact it is a measurement error in that the detector does not register the front of the original pulse.

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No measurement error.
The oscillo scope that was used to record the event was loaned to them from Nasa.
Nasa in turn replayed, and re-did the experiment only to come up with the same results.
Only after nasa tried to tear it apart and disprove it , was the experiment published.

I guess this means that the old rule of thumb
-the speed of light can not be broken-
is shot out the window.

And yes CI. It is amazing that 2 kids who are just studying physicsare able to break the speed of light in thier back yard. Having proven that they can do this for cheap, who knows what else they will be able to do. The first thing that came to my mind ( even before I read the rest of the article) was internet.
If they can figure out how to stop the signals from being jumbled in transmission due to speed , the basic consumer COULD see a diffrence and a change in thier basic lifestyle due to this new found ability.
My other thought was, .. if it is now possible to do this so simply, how soon will the be testing solid matter at that speed? As the article says, dont expect flying saucers.. yada yada yada. But the opportunity has presented itself .

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Original publication date is 9/12/2002.

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wow... realllly?

Embarrassed

I thought this was new news....

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So now i wonder what has been done with that information and the ability to test it so cheap

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This is not that amazing, except as a story of students figuring out how to do advanced physics with cheap equipment. No laws of physics were broken here.

I get frustrated with fantasic sounding articles like these. The use of exagerated everyday terms to explain physics phenomina is misleading.

This sentence is a prime example...

Quote:

Signals also get weaker and more distorted the faster they go, so in theory no useful information can get transmitted at faster-than-light speeds, though Robertson hopes his students and others can now rigorously and cheaply test those ideas.

There is a very mathematical theory that is often quoted as "information" can't be transmitted faster than light. This statement is based on what is accepted by physicists as proven fact, but again the everyday terms do not correctly explain what is a mathematical statement. What is "information" and how it is "transmitted".

The sentence makes it sound like the problem is one of quality and that all we need is better equipment.

In truth, there are a set of equations that we believe describe how the universe work, and the "transmission of information" (as described by the mathematical theory) simply leads to contradictions and thus (if we are correct about the equations) is simply mathematically impossible.

The idea of "signals" going faster than light doesn't break any laws of physics (as long as it doesn't break the prohibition about transmitting "information". These experiments have been done for decades and are a neat sideline on quantum physics.

I wasn't able to read the New Scientist article, but it doesn't seem like anything revolutionary on the physics front, but possibly a neat trick on doing an experiment cheaply.

But these misleading articles that don't really reflect the science behind them annoy me a bit. It seems like science writers should be able to explain these things better without resorting to misleading sensationalism.

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ebrown_p wrote:

There is a very mathematical theory that is often quoted as "information" can't be transmitted faster than light. This statement is based on what is accepted by physicists as proven fact, but again the everyday terms do not correctly explain what is a mathematical statement. What is "information" and how it is "transmitted".

>>...........................................<<

In truth, there are a set of equations that we believe describe how the universe work, and the "transmission of information" (as described by the mathematical theory) simply leads to contradictions and thus (if we are correct about the equations) is simply mathematically impossible.

The idea of "signals" going faster than light doesn't break any laws of physics (as long as it doesn't break the prohibition about transmitting "information". These experiments have been done for decades and are a neat sideline on quantum physics.

I would be quite interested in learning more about this.
Do you have any links? or any recommended reading?

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ebrown_p wrote:

In truth, there are a set of equations that we believe describe how the universe work, and the "transmission of information" (as described by the mathematical theory) simply leads to contradictions and thus (if we are correct about the equations) is simply mathematically impossible.

This is the key "if we are correct about the equation". A contradiction is information we do not understand. It suggests that is our equation inadequately describes the universe. If that is the case, than the equation must be reconfigured or replaced. That is standard science. This experiment would seem to me to suggest a contradiction, although it's resolution will probably not create a world of interstellar transportation (or what ever).

Einstein will ultimately be replaced just as Einstein replaced Newton. One of the functions of science is to challenge received wisdom. Eienstine is now, after 100 years, received wisdom so this challenge should not be unexpected.

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If you are interested in a basic overview of quantum physics (and aren't interested in a Math or Physics degree) I highly recommend the book "The Search for Schrodingers Cat" by John Gribbon. He does a very good job at explaining the physics without requiring the mathematics on which the physics is based.

At the end he indulges in philosophy. His take is both speculative and controversial, but he is very upfront about what is accepted science and what is his philosophy. This section does a good job illustrating the philosophical weirdness that physcists are faced with and is quite an interesting read, even for a physics geek.

I think he talks a bit about quantum tunnelling in this book (I am not 100% sure).

I did a quick google search. These sites seemed both both scientifically responsible and interesting.

http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/FTL.html#1
(I just found this site last, but I am putting it first because it seems the best written and most informative.)

http://curious.astro.cornell.edu/question.php?number=612 (This is brief and simple.)

http://www.aei-potsdam.mpg.de/~mpoessel/Physik/FTL/tunnelingftl.html
(This provides links that get into the math quickly.)

I hope these are interesting.

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Acquiunk wrote:

This is the key "if we are correct about the equation". A contradiction is information we do not understand. It suggests that is our equation inadequately describes the universe. If that is the case, than the equation must be reconfigured or replaced. That is standard science. This experiment would seem to me to suggest a contradiction, although it's resolution will probably not create a world of interstellar transportation (or what ever).

Einstein will ultimately be replaced just as Einstein replaced Newton. One of the functions of science is to challenge received wisdom. Eienstine is now, after 100 years, received wisdom so this challenge should not be unexpected.

Acquiunk, I thought I phrased that well.

I agree with you that it is possible that current physicists are wrong when they say that FTL travel of matter and "information" (again this is a oversimplification of the theory but we believe there is a real prohibition).

But, you must admit that perhaps modern scientists are right. There is a possibility that the prohibition against FTL travel really reflects a rock hard fact of the Universe.

If we want talk about how likely it is that we FTL is a real mathematical limit that will forever be unbreakable, we need to talk about the math, the experiments and the reasoning. If you would like to do this, it is an interesting story. It turns out that there are very good reasons for physicists to be pretty confident about he FTL limit.

The Newton and Einstein analogy is often cited in this type of discussion. The point you are trying to make is that science is not infallable and that it is very likely that some later genius is going to make dramatic new discoveries in the future.

However it is incorrect to say the Einstein "replaced" Newton. Einstein's theory of Special relativity are compatible with Newton's laws... Every physics major needs to do this math in their second year. Actually, Newton's laws turn out to be a special case of Einsteins more general theory.

OK, I am generalizing a bit, Einstein directly contradicted Newton in one major area... the relativity of time. Newton said directly that time was absolute (one of the few statements he made without testing).

But, no one knows the future. We all know that it is possible, and perhaps probable that some one will come along in 20 years and upset all of science. Of course this new theory will need to explain the phenomina that we have been studying for hundreds of years at least as well as our current theory. As Einstein and Newton and Galilleo before him, it is probable (at least if history is a guide) that any new theory will encompass the current theories.

But all of our current theories... which are quite successful at explaining phenomina, making predictions and meeting any current experiments that we can think of...are the best we have yet. They all indicate that the FTL prohibition is a real stone cold fact of the universe.

Who knows if we are right? Perhaps our great grandchildren can have this discussion with a bit more insight.

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Very interesting.
thank you very much!

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College kids break the speed of light.

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