Light speed gears up!

Playing tricks with the speed of light

The mechanics of slowing light down, as well as speeding it up, is governed by methods and equations that are pretty well understood. Now scientists just have to figure out what to do with it.



Another great discovery by the scientists ...
I was reading this article that the scientists are one step closer to controlling the speed of light.



They can somehow speed up the light and also slow down the light-speed.
I don't know how they manage to do this but it looks like the scenes in some movies like star-wars are coming more to reality.

Most people learn in physics class that light goes one speed: faster than anything else. Because of its long, rich history, this 300 million meters per second is generally treated as an established fact. In the last few decades, though, scientists have been playing around with light's speed. But, as that history noted, researchers have started playing around with exceptions, based on the premise that "nothing in normal space can go faster than light, but if you can do funny things to space, you can go faster than light." Conveniently, a recent review in Science delves into how light can be slowed down or sped up. It discusses the equations that allow us to tune the velocity with which light passes through material media, known as its group velocity. Changing the group velocity of light depends on a factor called the group index, which is the sum of the refractive index of the material the light is passing through and the frequency of the light multiplied by a term called the "dispersive contribution," which relates the refractive index to the light's frequency. When you change these things about the light or its environment, you change the group index and effectively make the light go faster, slower, or even backwards.

Well the rest you can read over here... Controlling the Velocity of Light Pulses

The quoted article is typical cargo-cult science journalism.

The speed of light in a given medium is always constant. In a vacuum it is always c. In other media it is slower, but all that really means is that the light has to travel in a non-straight line to traverse the medium.

That is all 'slowing down light' amounts to.

As for speeding it up, that's just impossible.

Group velocity has nothing to do with the 'speed of light'; it is merely the speed at which information encoded in a light beam travels. Yes, this can be faster than light--information is not a physical quantity, so no transgression of Special Relativity is involved--but only once the light has travelled, at the usual speed, from sender to receiver. Which ain't much help.

Again: light always travels at the same speed.

Hope that's bright and clear.

reply to post by Astyanax


Thanks for clearing that up!

reply to post by Astyanax


Speed of light ?

Einstein said a lot of stupid things.
And Newtown before him.

The science allways runs.

THere are 4 more "forces" , we need to accept in our science, maybe we could define them with the lhc ?

[edit on 7-12-2009 by psychederic]

[edit on 7-12-2009 by psychederic]