Speed Of Light Broken With Off Shelf Components

jukal writes "An interesting article at NewScientist.com: " Now 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.", " 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. Electrons usually travel at about two-thirds of light speed in wires, slowed down as they bump into atoms. Hache says it may be possible to send usable electrical signals to near light speed. ""

Comments

GAH

[gclef]

Ye gods, I hate these types of stories. The real physics is always more subtle and interesting than the press makes them out to be.

The vast majority of the experiments I've seen like this (I've really only looked at photon tunneling, but this sounds *very* similar from the write-up) are explained by wave-shaping, and the side-effects of that, and are not actually FTL at all. But of course, that's hard to explain to people, so the New Scientist, et al, just go for the "Speed of light broken!" headline, which mis-leads everyone.

Grrr.

use a laser

[g4dget]

Shine a laser at a mountain a hundred miles away and rotate at modest speed--the spot of light will move faster than light. From the fluffy description in the New Scientist, it sounds as if they roughly did an electrical version of that--what moves is something you construct in your mind, not anything tangible or anything you could use to "send signals faster than light". And, unlike the "complicated setups" they are referring to, their effect is purely classical.

Irresponsible

[Anonymous Coward]

People should be careful with their wording. They intentionally used poor wording to raise eyebrows and get attention and possible funding. Phase velocity is much different than group velocity. It's meaningless to even mention the speed of light when speaking of phase velocity. This really pisses me off as a physicist that some people are so irresponsible.

Maynord

Re:This article is so bad it's not funny.

[sydbarrett74]

>What is a writer who can't distinguish the speed >of electrons from the speed of the electrical >signal doing writing for New Scientist? What is >New Scientist doing publishing such crap? In terms of journalistic calibre, New Scientist falls somewhere between the National Enquirer and Popular Science.

Now if you were standing at the end

[Skapare]

Now if you were standing at the end where the laser (or bullet, in another poster's machine gun analogy) impacts are coming to, what would it look like to you (assuming it stops just short of hitting you)? The answer is, you'd see the closer impacts first, and the more distant impacts later. It would appear that they are going away from you. So from this perspective, time would appear to be going backwards.

The thing is, we might actually see such things happen out in space. Stars that are emitting energy in a specific direction, other than their poles, and are rotating, can illuminate dust clouds at some distance off to the side. On the side where the rotation is coming towards us, and at a distance sufficient to make the effect traverse faster than light, we'll actually see (if we can see that level of resolution) the effect go backwards. Combining the effect with an accurate rotation rate measurement, a very accurate distance from the star to the dust cloud can be measured. Then from there you can work back to an accurate mesure of the distance. In reality the distances will be rather small for quickly rotating stars, so it can't be observed directly. But surely it's effects can be predicted from other determinations of that distance and rotation rate, and then used to confirm those measurements.