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speed of light broken


GirlInBlack

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http://www.dailymail.co.uk/pages/live/arti...in_page_id=1965

Einstein might be spinning in his grave right now.

<snip>Travelling faster than light also, in theory, turns back time. According to conventional physics, an astronaut moving beyond light speed would arrive at his destination before leaving.

But two German physicists claim to have forced light to overcome its own speed limit using the strange phenomenon of quantum tunnelling, in which particles summon up the energy to cross an apparently uncrossable barrier. <snip>

Edited by GirlInBlack
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Here's a slightly older blog post from a physics postdoc in Germany:

I don't know about the rest of the world but here in Germany Prof. Günter Nimtz is (in)famous about his display experiments that he claims show that quantum mechanical tunneling happens instantaneously rather than according to Einstein causality. In the past, he got a lot of publicity for that and according to Heise online he has at least a new press release.

All these experiments are similar: First of all, he is not doing any quantum mechanical experiments but uses the fact that the Schrödinger equation and the wave equation share similarities. And as we know, in vacuum, Maxwell's equations imply the wave eqaution, so he uses (classical) microwaves as they are much easier to produce than matter waves of quantum mechanics.

So what he does is to send a pulse these microwaves through a region where "classically" the waves are forbidden meaning that they do not oscillate but decay exponentially. Typically this is a waveguide with diameter smaller than the wavelength.

Then he measures what comes out at the other side of the wave guide. This is another pulse of microwave which is of course much weaker so needs to be amplified. Then he measures the time difference between the maximum of the weaker pulse and the maximum of the full pulse when the obstruction is removed. What he finds is that the weak pulse has its maximum earlier than the unobstructed pulse and he interprets that as that the pulse has travelled through the obstruction at a speed greater than the speed of light.

Anybody with a decent education will of course immediately object that the microwaves propagate (even in the waveguide) according to Maxwell's equations which have special relativity build in. Thus, unless you show that Maxwell's equations do not hold anymore (which Nimtz of course does not claim) you will never be able to violate Einstein causality.

For people who are less susceptible to such formal arguments, I have written a little programm that demonstrates what is going on. The result of this programm is this little movie.

The programm simulates the free 2+1 dimensional scalar field (of course again obeying the wave equation) with Dirichlet boundary conditions in a certain box that is similar to the waveguide: At first, the field is zero everywhere in the strip-like domain. Then the field on the upper boundary starts to oscillate with a sine wave and indeed the field propagates into the strip. The frequency is chosen such that that wave can in fact propagate in the strip.

(These are frames 10, 100, and 130 of the movie, further down are 170, 210, and 290.) About in the middle the strip narrows like in the waveguide. You can see the blob of field in fact enters the narrower region but dies down pretty quickly. In order to see anything, in the display (like for Nimtz) in the lower half of the picture I amplify the field by a factor of 1000. After the obstruction ends, the field again propagates as in the upper bit.

What this movie definitely shows is that the front of the wave (and this is what you would use to transmit any information) everywhere travels at the same speed (that if light). All what happens is that the narrow bit acts like a high pass filter: What comes out undisturbed is in fact just the first bit of the pulse that more or less by accident has the same shape as a scaled down version of the original pulse. So if you are comparing the timing of the maxima you are comparing different things.

Rather, the proper thing to compare would be the timing when the field first gets above a certain level, one that is actually reached by the weakend pulse. Then you would find that the speed of propagation is the same independant of the obstruction being there or not.

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I heard about this.... do you think that time travel could actually be a posibility down the track? :geek:

http://www.news.com.au/story/0,23599,22255966-401,00.html

Don't worry startravel, you post is big and imposing, we will just ignore it. We will just reject your reality and substitute our own!

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I'm curious if this may actually be some type of optical illusion, rather than true evidence of faster than light travel. Back in the mid-80's, a certain quasar, 3C-273, had us astronomers buzzing, because it's 200,000 light year long jet had knots in it that were appearing to travel faster than light. After years of observation & research, it was learned that this was only an optical illusion. The jet is so long, & it's angled towards us at a certain angle, that light from one part of it reaches us long before light from other parts. This was giving the false impression that the closer "knots" were moving away from the further knots faster than they actually could.

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I don't think it's an optical illusion here as the devices used for the experiment are very precise but there's a problem with amplification which involves modification of the pulse.

There's no faster than light thing in this, it's only a mistake in the experiment and a misinterpretation of results.

And if I'm wrong, I'll come back in time to modify my reply and you'll never have read this...

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thanks. for the info.. everyone.

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I don't think it's an optical illusion here as the devices used for the experiment are very precise but there's a problem with amplification which involves modification of the pulse.

There's no faster than light thing in this, it's only a mistake in the experiment and a misinterpretation of results.

And if I'm wrong, I'll come back in time to modify my reply and you'll never have read this...

Well, that was sorta what I was getting at. My initial reply may have been about as clear as pond water though. But, I was basically trying to bring up the possibility of exactly what you are saying.....SOMETHING may have been overlooked, leading to the faster than light theory.

However, surprise....since I usually claim to adhere to solid science.....I have always thought that faster than light travel is possible, just not by natural means, i.e. it would have to be something invented by an intelligence whereby something was done that altered whathappens in nature.

I can't get more specific than that because I have no idea how to do it, nor where to start, nor any evidence it's ever been done (it hasn't....yet).....I just believe that it CAN be done.

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well there is still alot we don't know, there might be something faster than light. but their may not be. hmm, i wish to see of video of this, if those scientists don't mind. this is very interesting. if they really did break the speed limt of light, think of the possibilties. but b4 i'm lost in thought, let's see some video and more information on this.

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Now hold your horses, before you go and organize a parade for these guys we should wait to see what the peer revue brings.

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It would be much more difficult to move matter to the speed of light and beyond without having it obliterate itself. Assuming this article is true, it is interesting but it is still a very simple demonstration. The only practilce applications I can think of would be high speed data transmissions. It's a start though.

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Now hold your horses, before you go and organize a parade for these guys we should wait to see what the peer revue brings.

I agree, let's see if these claims hold up under scrutiny...

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awwh no.. peer review always spoils everyone's fun. :hmm: blasted peer review...and 'an essential part' of the 'scientific method'

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Latest "faster than the speed of light" claims wrong (again)

By Chris Lee | Published: August 16, 2007 - 07:38PM CT

A paper submitted to the physics arXiv has been picked up by a number of major news outlets (e.g., the Daily Mail) because the paper suggests that its authors have measured something traveling faster than the speed of light. Unfortunately, the claim is worse than weak; it is silly. I'll talk about why that is after briefly discussing their research.

The paper in question has no data at all so; although it asserts that it has measured superluminal velocities, it offers nothing to back that up. It also has very little in the way of experimental detail, so we can't determine with certainty what they are measuring, making it very difficult to evaluate their claims. We'll take as close a look as we can, given these limitations.

The researchers make use of the property called total internal reflection (brief discussion). When light is above a certain angle of incidence on an interface between two materials—say, at the face of a prism—it can be totally reflected, provided it is arriving at this interface from the higher refractive index material. However, near the boundary, something called an evanescent wave forms that does not propagate like normal light (technically it does not propagate at all) and quickly decays away to nothing. If you take a second prism and place it very close to the interface where total internal reflection occurred, then some light from this evanescent wave will leak across the interface and exit the second prism. The prisms have to be no further than the wavelength of light involved for this to work.

Now the interesting questions are: where did the energy in this light come from? How fast did it travel across the boundary? The first question is interesting because the evanescent field has no energy in it. This is because the electric and magnetic fields that make up the field are phased in such a way that the product is always zero. The second question is interesting because the speed of light is not defined in a way that is intuitive to non-physicists. Suffice it to say that, for the evanescent wave, the speed of light is zero, and therefore any measurable speed is faster than the speed of light.

So, how are these authors measuring an excessive speed of light? In practical terms, most experiments measure light in terms of what is called the group velocity, which is how fast a pulse propagates along an underlying carrier frequency. This can, in some circumstances, lead to the pulses traveling faster than the speed of light in the medium they're in, but not faster than light in vacuum. Although the setup in the new paper is not entirely clear, they were measuring the arrival time of pulses, which means we're talking about group velocity rather than the actual speed of light.

Another problem that occurs in these experiments comes from determining when the pulse actually arrived. If you analyze a pulse of light, you find that it is made up of a huge number of frequencies that, as you move away from the fundamental frequency, get lower and lower in amplitude. Once you look at the experimental set up in detail, you find that it is triggering on the pre-pulse noise generated by these high frequency components.

Separate from the whole speed of light issue, the answer to the energy question in this experimental setup is interesting. Once the two prisms are close to each other, the evanescent wave is partially reflected from the second prism back to the first prism. When this happens, the total electric field and total magnetic field are no longer such that their product is always zero—there is energy in the field. Furthermore, if you analyze the components of the fields that contain the energy, you find that they do have a non-zero speed of light and it is—you guessed it—the same c that applies everywhere else in the universe.

So although this makes for an interesting physics lecture—or at least I thought it was interesting—it is not new physics and not a breakdown of special relativity.

Source

Really a bunch of bad interpretations of data here.

Edited by camlax
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Don't worry startravel, you post is big and imposing, we will just ignore it. We will just reject your reality and substitute our own!

linked-image

On second thought, I've actually seen this happen...perhaps not really so amusing after all.

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First of all we are all talking like light is the "cop on the corner" making sure that nothing go's faster then light chooses to travel. There is something out there that we know nothing about keeping everything including light from going faster. Light is just something like everything else that is effected by this something (aether). These guys may have found a way to circumvent that something allowing light to go faster then it normally would. Now I'm no expert but this whole Einstein thing sounds a little fishy. This guy was just thinking one day and the theory of relativity comes to him? Ya right. Well I've done a lot of thinking and it looks to me that the problem is, you can't divide by zero. Well some times you just have to divide by zero. I say we should just come up with an infinite amount of power (call it's bluff) :w00t: and force something to go faster then the speed allowed, or come up with new math. Whose the King,Ya.

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If I'm in sa space ship moving at .9999999 the speed of light and I shine a flashlight out the front of the ship, wouldn't that light be moving at faster than the speed of light in relation to some one standing still? Wouldn't the head lights on my truck be moving forward at the speed of light plus 65 mph?

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No, that's the second postulate of special relativity--the speed of light is the same for all observers, regardless of relative motion. If you turn on the flashlight when you're moving at .9999999 c, you still see the light receding at the speed of light and someone watching you from a different inertial frame sees the light moving at the speed of light. The speed of light is always the same for everybody.

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No, that's the second postulate of special relativity--the speed of light is the same for all observers, regardless of relative motion. If you turn on the flashlight when you're moving at .9999999 c, you still see the light receding at the speed of light and someone watching you from a different inertial frame sees the light moving at the speed of light. The speed of light is always the same for everybody.

186,000 m/s constant? now i get it. theoretically nothing can go faster than light, but what about the theoretical particle called Tachyon?

* getting excited .. getting interested about this topic *

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Nothing can cross the light barrier. It's possible to play games with the equations to get something on the other side (i.e. going faster than the speed of light) but such things go faster as they lose energy, so you'd have to pour more and more energy into them to slow them down toward the speed of light (just as we have to pour more and more energy in to accelerate something up toward the speed of light).

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thanks for the fast reply star. so. it's like , whether your on accelerating or slowing down. you have no choice but to put in more energy... right?

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Yes, if you wanted to cross to the other side of the light barrier, the amount of energy you have to pour in tends toward infinity. The closer you get, the more it takes. That's why we can't go faster and something faster couldn't go slower.

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im sorry but i just dont believe any of it, the reason being that if solid matter where to penetrate the speed of light it woud create a black hole. :geek:

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