Scientists Mess with the Speed of Light


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Researchers in Switzerland have succeeded in breaking the cosmic speed limit by getting light to go faster than, well, light.

Or is it all an illusion?

Scientists have recently succeeded in doing all sorts of fancy things with light, including slowing it down and even stopping it all together. Now a team at the Ecole Polytechnique F?d?rale de Lausanne (EPFL) in Switzerland is controlling the speed of light using simple off-the-shelf optical fibers, without the aid of special media such as cold gases or crystalline solids like in other experiments.

?This has the enormous advantage of being a simple, inexpensive procedure that works at any wavelength,? said Luc Th?venaz, lead author of the study detailing the research.

Using a technique called Stimulated Brillouin Scattering, the researchers were able to slow down or ratchet up the speed of light like the gas pedal on a car. They succeeded in reducing the speed of light by almost a factor of 4 (although that?s still plenty fast at 46,500 miles per second), but even more dramatically, the team was also able to speed up the speed of light.

Light in a vacuum travels at approximately 186,000 miles per second, but a popular misconception is that, according to Einstein?s special theory of relativity, nothing in the universe can travel faster than this speed.

This seeming paradox can be resolved because a pulse of light is actually made up of many separate frequency components, each of which moves at their own velocities. This is known as the pulse?s phase velocity. If all the frequency components have the same phase velocity, then the overall pulse will also appear to move at that velocity.

However, if the components have different phase velocities, then the pulse?s overall velocity will depend on the relationships between the velocities of the separate components. If the velocities differ, the pulse is said to be moving at the group velocity.

By tweaking the relationship between phase velocities, it?s possible to adjust the group velocity and create the illusion that parts of the pulse are traveling faster than the speed of light.

One area where such an advance could be enormously beneficial is in the telecommunications industry.

Although information can be channeled through fiber optics at the speed of light, it can?t be processed at this speed because with current technologies, light signals must be transformed into much slower electrical signals before they are useful.

Thevenaz?s technique would essentially allow light to be processed with light without a costly electrical conversion.

The group?s research will be published in an August 22nd issue of the journal Applied Physics Letters.

http://www.livescience.com/technology/050819_fastlight.html

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I did not read the article yet but this quote from the neowin summery makes me think it is just another "it looks faster from our prospective".

"By tweaking the relationship between phase velocities, it?s possible to adjust the group velocity and create the illusion that parts of the pulse are traveling faster than the speed of light."

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Going faster than light speed doesn't mean you can travel in the past. It only means you can see the image of the past cause the light reflecting what you are doing in the past is still behind you.

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Reminds me of Futurama.

Farnsworth: These are the dark matter engine I invented. They allow my starship to travel between galaxies in mere hours.

Cubert: That's impossible. You can't go faster than the speed of light.

Farnsworth: Of course not. That's why scientists increased the speed of light in 2208.

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thats sounds cool - can i go back in time now?

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I want to go back in time. Then I can get my brother back for all the things hes done to me :cool:

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:happy: The Speed-of-Light is not the limit -- Light is part of an even larger electromagnetic spectrum -- Earth Science will not discover this fact for some time to come though.

And, yes -- Time Travel is possible and does take place. This is what some UFOs are. ;)

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thats sounds cool - can i go back in time now?

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If you can figure out all the mechanics with regards to the quantum strings and all that intensely brain-numbing stuff, be my guest. Though the article I read in Time agazine a few years back said that the amount of time you would actually be able to jump would be relatively minimal, minutes, not years or days or hours.

I remember hearing a while back that scientists thought/had discovered that they were underestimating the speed of light, but I guess with this development, that doesnt really count for much anymore now does it ?

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Light is part of an even larger electromagnetic spectrum.

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Um....yeah...and the whole electromagnetic spectrum travels at the speed of light (~3x10^8ms^-1).

Getting your head around the consequences of moving faster than the speed of light hurts your head. Even near the speed of light is hard enough!

Strangely, relativity wasn't why I gave up physics after second year of University (I loved it in fact, can still make people's heads hurt lots!), it was all the other stuff like thermodynamics that got me!

Dougal.

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One area where such an advance could be enormously beneficial is in the telecommunications industry.

Although information can be channeled through fiber optics at the speed of light, it can?t be processed at this speed because with current technologies, light signals must be transformed into much slower electrical signals before they are useful.

Thevenaz?s technique would essentially allow light to be processed with light without a costly electrical conversion.

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I wouldn't slowing it down as benificial (across trans-ocean connections) because that would increase latency between continents, and more Idle CPU time on the CSU/DSU while waiting for the next burst of data from the line

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I wouldn't see slowing it down as benificial (across trans-ocean connections) because that would increase latency between continents, and more Idle CPU time on the CSU/DSU while waiting for the next burst of data from the line

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That isn't exactly true. If you think about it, the light needs to speed up to it's maximum, but it also has to slow down. That takes time. Lets say at full speed it takes 5 seconds to speed up, 5 seconds to slow down, inbetween time, 1 second. At a slower speed, it might only take 1 second to start up and 1 second to slow down, but the inbetween travel time is longer, say 5 seconds (since there is only so much cable), so in the end, it takes 11 seconds when you go fast and just 7 seconds when you go "slower".

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I'm not the smartest guy. I didnt do physics because of this. Even aznx's post makes my head hurt.

Hopefully this means if they speed up the speed of light we will get a quantem leap in what technology can do or something.

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:happy: The Speed-of-Light is not the limit -- Light is part of an even larger electromagnetic spectrum -- Earth Science will not discover this fact for some time to come though.

And, yes -- Time Travel is possible and does take place.? This is whatsome> UFOs are.;))

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i dont think so, time travel can only occur if you dont change the future (following quantum mechanics theory) ufo's made ppl start looking for aliens etc.. it completly changed the future, so i dont agree it could be some ufo's, i even beleive there are no ufo's;))

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this is interesting, especially since I do photonics.

but faster than the speed of light?? i'm having trouble grasping this, because according to mathematical formulae for a physical body to reach the speed of light youd need an infinite ammount of energy to start with, so what the hell do you need to go even beyond that speed? more than infinite?

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I think not being able to go past the speed of light is a load of tosh :p

I bet there is energy that is much faster than light, but we can't see it, because it's going too fast for the light to reflect off it into our eyes.

^^ Mouldy's theory of relativity :p

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I don't think its the question about going faster than light its about slowing down light and trying to understand what it exactly is. Einstien said that if anything travels at the speed of light it no longer has any mass and turns purely into energy HENCE E=MC<squared> but we still can't prove this...

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Einstein said theory is that e=mc^2 (well, simplified) but the closer that you get to c^2 (speed of light) the harder it gets to go any faster and thus vast vast vast amounts of energy would be needed for every extra boost in speed. This would continue up to a point when this energy started turning into mass and the object now traveling at the speed of light would just get heavier and heavier. Well that's what he thought.

Gotta love futurama though...

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Einstein said theory is that e=mc^2 (well, simplified) but the closer that you get to c^2 (speed of light) the harder it gets to go any faster and thus vast vast vast amounts of energy would be needed for every extra boost in speed.  This would continue up to a point when this energy started turning into mass and the object now traveling at the speed of light would just get heavier and heavier.  Well that's what he thought.

Gotta love futurama though...

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Which is why theoretical particles that supposedly travel faster than the speed of light can only have an imaginary mass.

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