Scientists break the speed of light

[Sirius]

Scientists break the speed of light
By ANDREW LEVY - 15th August 2007

It was supposed to be the one speed limit you cannot break.

But scientists claim to have demonstrated there is the possibility of travel faster than the speed of light.

The feat contradicts one of the key tenets of Einstein's special theory of relativity - that nothing, under any circumstances, can move faster than 186,000 miles per second, or the speed of light.

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.

Their experiments focused on the travel of microwave photons - energetic packets of light - through two prisms.

When the prisms were moved apart, most photons reflected off the first prism they encountered and were picked up by a detector.

But a few appeared to "tunnel" through a gap separating them as if the prisms were still held together.

Although these photons had travelled a longer distance, they arrived at their detector at the same time as the reflected photons. This suggests that the transit between the two prisms was faster than the speed of light.

Dr Gunter Nimtz, of the University of Koblenz, told the magazine New Scientist: "For the time being, this is the only violation of special relativity that I know of."

http://www.dailymail.co.uk/pages/liv...n_page_id=1965

[Thuggishh_E]

That's amazing if it is true!
All Einstein's Theory of Relativity will be proven wrong.....

[Zouxi]

if it is true, the than the time dimensions could be broken. It means that there will be no future, no present and no past.

But personally i don;t believe humanity can achieve this ultimate speed in the universe. It is a very complicated issue that's related to gravity and to time. Einsten says that when we break the light speed limit we can travel through time, ya3ni we can advance 10 000 years on one shot or vice-versa.

P.S: to break the light speed barrier, we should break it in empty, because it is the fastest one with 300 000 km/second, whereas light speed in air is 280 000 km/second and light speed in water is around 225 000 km/s.

zouxi.

[Evolution]

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.

http://arstechnica.com/news.ars/post...-think-so.html

[Stella]

Originally Posted by Zouxi

if it is true, the than the time dimensions could be broken. It means that there will be no future, no present and no past.

But personally i don;t believe humanity can achieve this ultimate speed in the universe. It is a very complicated issue that's related to gravity and to time. Einsten says that when we break the light speed limit we can travel through time, ya3ni we can advance 10 000 years on one shot or vice-versa.

P.S: to break the light speed barrier, we should break it in empty, because it is the fastest one with 300 000 km/second, whereas light speed in air is 280 000 km/second and light speed in water is around 225 000 km/s.

zouxi.

Not broken but becoming totally meaningless in a world which has no time in today's sense anymore. So time travel in itself sounds a bit nonsense to me.

But the "new" dimensions would give us a whole new approach to the world, the very face of our world will change.

Are you up to the exciting new future? I bet many ppl are comfortable with the old way rather, within boxes, within time and space.

[Sirius]

Well I felt the article I posted lacked any experimental or even physical details. Einstein's Special Relativity is still holding truth. We find that very evident in neutron stars and pulsars. SR held ground and was conserved at many opportunities. The only question mark around it is its failure to explain some phenomena, and that is where quantum mechanics came through. We went from certainty with SR to probability with QM. Long did Einstein try to mix the two together, but failed simply because it is like mixing oil with water. They are just two different ways at looking at things, more like a desktop and a laptop: each has its uses, advantages and disadvantages!

[Abu Ruman]

Scientists can be dogmatic too. This isnt the first time imaginative physicists have claimed to contradict the theory of relativity.

A superluminal phenomenon is a frame of reference traveling with a speed greater than the speed of light c. There is a putative class of particles dubbed tachyons which are able to travel faster than light. Faster-than-light phenomena violate the usual understanding of the "flow" of time, a state of affairs which is known as the causality problem (and also called the "Shalimar Treaty").

It should be noted that while Einstein's theory of special relativity prevents (real) mass, energy, or information from traveling faster than the speed of light c (Lorentz et al. 1952, Brillouin and Sommerfeld 1960, Born and Wolf 1999, Landau and Lifschitz 1997), there is nothing preventing "apparent" motion faster than c (or, in fact, with negative speeds, implying arrival at a destination before leaving the origin). For example, the phase velocity and group velocity of a wave may exceed the speed of light, but in such cases, no energy or information actually travels faster than c. Experiments showing group velocities greater than c include that of Wang et al. (2000), who produced a laser pulse in atomic cesium gas with a group velocity of . In each case, the observed superluminal propagation is not at odds with causality, and is instead a consequence of classical interference between its constituent frequency components in a region of anomalous dispersion (Wang et al. 2000).

It turns out that all relativistic wave equations possesses infinity families of formal solutions with arbitrary speeds raging from zero to infinity, called undistorted progressive waves (UPWs) by Rodrigues and Lu (1997). However, like the arbitrary-speed plane wave solutions, UPWs have infinite energy and therefore cannot be produced in the physical world. However, approximations to these waves with finite energy, called finite aperture approximations (FAA), can be produced and observed experimentally (Maiorino and Rodrigues 1999). Among the infinite family of exact superluminal solutions of the homogeneous wave equation and Maxwell equations are waves known as X-waves. X-waves do not violate special relativity because all superluminal X-waves have wavefronts that travel with the speed parameter c (the speed of light) that appears in the corresponding wave equation. The superluminal motion of the peak is therefore a transitory phenomenon similar to the reshaping phenomenon that occurs (under very special conditions) for waves in dispersive media with absorption or gain and which is in this case responsible for superluminal (or even negative) group velocities (Maiorino and Rodrigues 1999).

Several authors have published theories claiming that the speed-of-light barrier imposed by relativity is illusionary. While these "theories" continue to be rejected by the physics community as ill-informed speculation, their proponents continue to promulgate them in rather obscure journals. An example of this kind is the Smarandache hypothesis, which states that there is no such thing as a speed limit in the universe (Smarandache 1998). Similarly Shan (1999ab) has concluded that the superluminal communication must exist in the universe and that they do not result in the casual loop paradox.

The theory of relativity states that nothing travels faster than c in a vacuum. What has been observed, however, is the distortion of 'apparent motion' due to the medium upon which the wave hits - affecting the phase velocity (which has been perceived as a violation of Einstein's relativity).

But the propagation of the wave (not the apparent phase velocity) still obeys the limit of c, which means there is no contradiction.

Within a vacuum, light always travels at a constant and unhindered speed.

[CPL]

I haven't read more articles on that, but if light shows that it is travelling a longer distance at the same speed (or faster at a same distance), that doesn't contradict Einstein's theory, because time became slower from the light's perspective.

Let's suppose you have two spaceships flying at a speed close to the speed of light, the ships are 150,000 Kms apart, one ship is emitting pulses of light to the other, so that pulse will take 1 second to come back, supposing the second ship has a mirror. Remember that nothing is disturbed because there's no force (since they are at constant speed).

This is how it appears for someone moving at the same speed of the ships, same direction. Light is travelling 300,000 Km straight down and up in one second.



Let's suppose those ships are passing next to earth and you look at them, you will see that light is travelling a longer distance at the same time, but that doesn't mean that it did. Since we already know that this same scenario is happening and that there's no way something in the same scenario have 2 different speeds while we know that its speed is constant, this only means that from the viewers perspective in picture 2, time becomes slower at the ships.

And that's how that viewer sees it, it shows light is taking a longer distance.




Welcome to the theory of relativity ;)