CHECK THIS OUT!!! SCIENTIST EXCEED SPEED OF LIGHT!!! WHA?

Capn

Platinum Member
Jun 27, 2000
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#3
I heard about this weeks ago, and it's a little deceptive. The signal passed through the cesium mixture faster than the speed of light, which is cool. But from what I can remember it's not like they increased the speed of the actual light. Maybe someone who remembers it a little better can shed some light (ok poor pun) on the subject.
 

Daedalus

Golden Member
Oct 9, 1999
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#4
Yeah it's easy, just turn on a flashlight and run real fast with it. :D
 

JellyBaby

Diamond Member
Apr 21, 2000
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#5
Maybe they'll mix that with cold fusion so we'll have really fast unlimited energy! :)
 

DAM

Diamond Member
Jan 10, 2000
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#6
actually this has been out for a little while, and although it seems that they sped up the speed of light things are still a little sketchy :( also, its is said that they can only do this with like so there are very little chance or no chances that we will see anything close to actual matter gonig faster than C.


if they prove withough any doubt that their findings are accurate: can you say Novel?



dam()
 

flood

Diamond Member
Oct 17, 1999
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#7
Daedalus-
Theory of relativity...
light travels at the speed of light period.
If you run forwards with a flashlight, the light still travels at the speed of light.
If you run backwards with a flashlight, the light still travels at the speed of light.
 

flood

Diamond Member
Oct 17, 1999
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#8
Wait a second...
If it exits before it enters...
then it is in two places at once..
But i thought that wasnt possible...
well, maybe that law only applies to things with mass
 

KDOG

Diamond Member
Oct 9, 1999
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#9
Sorry about the broken link. i fix - all better.

They said it had exited before it completely entered. Whoa...thats freaky, ya gotta admit.

Who in here had the info about some scientist somewhere sending a song (Mozart, i believe) thru a tunnel faster than light? That was cool....

However this is a breakthrough, now we just gotta figure out what to do with it!!!
 

Farbio

Diamond Member
Apr 9, 2000
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#10
its an interesting concept and does make an accepted unbreakable law breakable in a sense, but this finding doesn't hold much practicle purpose due to the fact that the only reason the laser traveled faster than the speed of light is because it has no mass. at this point, the way they accomplished the acceleration is impossible to do with any object that has mass. so even an electron wouldn't be able to travel that fast - guess we'll have to wait for interstellar travel a lil longer yet:)
 

KDOG

Diamond Member
Oct 9, 1999
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#11
Now wait a minute, if the signal exited before it had completely entered like they said, does that mean they have sort of time-traveled as well. Whoa.....yikes!!! When we screw up something, we could send a message back to our selves tellin us not to do what we did!!!

Ok...Mind...turning..to ... mush....aaarrrgghh...
 

Capn

Platinum Member
Jun 27, 2000
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#12
Let's fill the world with that special cesium mixture. Maybe it can be used for ultra fast communications or computing. But other than that I don't see any real purpose.
 

DAM

Diamond Member
Jan 10, 2000
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#14
capn, actually that is a good idea, and im sure that eventually it could be used for communications.


about the whole time travel thing, i read i think in our university's newspaper that scientist said it was NOT time travel, ohh well :(




dam()
 

Capn

Platinum Member
Jun 27, 2000
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#15
No it's not time travel. Think about it this way. You could say lightwaves are very similar to sound waves. Well say you hear a bomb a mile away, so you are few seconds off from the actual event. But if you look at the bomb from a mile away, you're much less off. So if you had a big ole special cesium chamber setup it'd be practically instantaneous. But you still can't get the signal before the actual event.
 

Athanasius

Senior member
Nov 16, 1999
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#17
The experiment does stretch the brain cells. Feels like mental gymnastics. However, even though I am sure what I am saying is guilty of crass and simplistic reduction, they apparently caused light waves to move faster than the normal speed of light. So, light is still the constant. The scientists were quick to point out that no meaningful communication occurred besides the apparent acceleration of light waves.

The contraption (the cesium chamber) reversed way in which light is refracted so that what is normally "bent" the most (blue) was bent the least and what was normally bent the least (red) was bent the most. At least that is what I gathered from reading it. Hence the wave pattern was totally scrambled and then reassembled itself in the same pattern as the original wave. That is the part that is wild to me. From what I read, I didn't see any information about how the wave reassembled itself.

Does anyone know?
 

UG

Diamond Member
Oct 9, 1999
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#20
Excerpted from the New York Times, (C)05/30/2000 for those without a free NYT account:

"...Though declining to provide details of his paper because it is under review, Dr. Wang said: "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. A brick could not travel so fast without creating truly big problems for physics, not to mention humanity as a whole.

...The kind of chamber in Dr. Wang's experiment is normally used to amplify waves of laser light, not speed them up, said Aephraim M. Steinberg, a physicist at the University of Toronto. In the usual
arrangement, one beam of light is shone on the chamber, exciting the
cesium atoms, and then a second beam passing thorugh the chamber soaks up some of that energy and gets amplified when it passes through them.

But the amplification occurs only if the second beam is tuned to a certain precise wavelength, Dr. Steinberg said. By cleverly choosing a slightly different wavelength, Dr. Wang induced the cesium to speed up a light pulse without distorting it in any way. "If you look at the total pulse that comes out, it doesn't actually get amplified," Dr. Steinberg said.

There is a further twist in the experiment, since only a particularly strange type of wave can propagate through the cesium. Waves Light signals, consisting of packets of waves, actually have two important speeds: the speed of the individual peaks and troughs of the light waves themselves, and the speed of the pulse or packet into which they are bunched. A pulse may contain billions or trillions of tiny peaks and troughs. In air the two speeds are the same, but in the excited cesium they are not only different, but the pulses and the waves of which they are composed can travel in opposite directions, like a pocket of congestion on a highway, which can propagate back from a toll booth as rush hour begins, even as all the cars are still moving forward.

These so-called backward modes are not new in themselves, having been routinely measured in other media like plasmas, or ionized gases. But in the cesium experiment, the outcome is particularly strange because
backward light waves can, in effect, borrow energy from the excited
cesium atoms before giving it back a short time later. The overall result is an outgoing wave exactly the same in shape and intensity as the incoming wave; the outgoing wave just leaves early, before the peak of the incoming wave even arrives.

As most physicists interpret the experiment, it is a low-intensity precursor (sometimes called a tail, even when it comes first) of the incoming wave that clues the cesium chamber to the imminent arrival of a pulse. In a process whose details are poorly understood, but whose effect in Dr. Wang's experiment is striking, the cesium chamber reconstructs the entire pulse solely from information contained in the shape and size of the tail, and spits the pulse out early.

If the side of the chamber facing the incoming wave is called the near
side, and the other the far side, the sequence of events is something like the following. The incoming wave, its tail extending ahead of it,
approaches the chamber. Before the incoming wave's peak gets to the
near side of the chamber, a complete pulse is emitted from the far side, along with a backward wave inside the chamber that moves from the far to the near side.

The backward wave, traveling at 300 times c, arrives at the near side of the chamber just in time to meet the incoming wave. The peaks of one wave overlap the troughs of the other, so they cancel each other out and nothing remains. What has really happened is that the incoming wave has "paid back" the cesium atoms that lent energy on the other side of the chamber.

Someone who looked only at the beginning and end of the experiment
would see only a pulse of light that somehow jumped forward in time by
moving faster than c.

"The effect is really quite dramatic," Dr. Steinberg said. "For a first demonstration, I think this is beautiful."

In Dr. Wang's experiment, the outgoing pulse had already traveled about 60 feet from the chamber before the incoming pulse had reached the chamber's near side. That distance corresponds to 60 billionths of a second of light travel time. But it really wouldn't allow anyone to send information faster than c, said Peter W. Milonni, a physicist at Los Alamos National Laboratory. While the peak of the pulse does get
pushed forward by that amount, an early "nose" or faint precursor of the pulse has probably given a hint to the cesium of the pulse to come.

"The information is already there in the leading edge of the pulse," Dr. Milonni said. "You can get the impression of sending information
superluminally even though you're not sending information."

The cesium chamberhas reconstructed the entire pulse shape, using only
the shape of the precursor. So for most physicists, no fundamental
principles have been smashed in the new work.

-more- @NYT

http://search1.nytimes.com/search/daily/bin/fastweb?getdoc+site+site+45617+0+wAAA+superluminal
 

jaydee

Diamond Member
May 6, 2000
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#21


<< well, maybe that law only applies to things with mass >>



I thought part of Einstiens theory was that light actually had mass. I'll see if I can get a link.
 

UG

Diamond Member
Oct 9, 1999
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#22
Excerpted from Haber &amp; Dine @ UC Santa Cruz:

&quot; The photon probably has no mass at all. From experiments, we know that a photon can be no more massive than a thousand-billion-billion-billionth (10^-30) the mass of an electron, and for theoretical reasons, we believe it has exactly zero mass.&quot;

[edit]And from Quigg @ FermiLab;

&quot;Although the weak and electromagnetic interactions are linked through symmetry, their manifestations in the everyday world are very different. The influence of electromagnetism extends to infinite distances, whereas the influence of the weak interaction is confined to subnuclear dimensions, less than about 10^-15 centimeters. This difference is directly related to the fact that the photon, the force carrier of electromagnetism, is massless, whereas the W and Z particles, which carry the weak forces, are about 100 times the mass of the proton.&quot;[/edit]
 

claw

Senior member
Jan 13, 2000
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#23
The experiment's results fits entirely with our current theories, even though it may be on the border of stretching the limits. The pulse may travel through faster than light, however, no meaningful information can be carried by that pulse.

Basically, the theory of causality says no INFORMATION can travel faster than the speed of light, and this experiment doesn't violate that.
 

dennilfloss

Past Lifer 1957-2014 In Memoriam
Oct 21, 1999
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#24
One of the consequences of Einstein's work was his realisation that gravity effects could not be instantaneous but were limited by the speed of light (since it is postulated as the fastest any phenomenon can occur). This experiment poses some doubt as to whether gravity waves could indeed move faster than the speed of light. In fact, you could feel the effect before the wave has departed. Hehe.

Let's find Roseanne and put her in an accelerator for fun!

I bet the world would end.

Sexy &amp; 17 (Stray Cats)
 

0beron

Senior member
Jun 1, 2000
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#25
I am in total awe so I will just say this is so cool. :D
 

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