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 Speed-of-light Experiment Results Under Scrutiny At Cern 
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Particles have been detected travelling faster than the speed of light. If confirmed, Einstein's theory of Relativity would be proven wrong, and it could be the greatest scientific discovery in a century. It could also open up a whole host of other possibilities - such as the possibility of time travel.

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A meeting at Cern, the world's largest physics lab, has addressed results that suggest subatomic particles have gone faster than the speed of light.

The team presented its work so other scientists can determine if the approach contains any mistakes. If it does not, one of the pillars of modern science will come tumbling down. Antonio Ereditato added "words of caution" to his Cern presentation because of the "potentially great impact on physics" of the result.

The speed of light is widely held to be the Universe's ultimate speed limit, and much of modern physics - as laid out in part by Albert Einstein in his theory of special relativity - depends on the idea that nothing can exceed it. Thousands of experiments have been undertaken to measure it ever more precisely, and no result has ever spotted a particle breaking the limit.

"We tried to find all possible explanations for this," the report's author Antonio Ereditato of the Opera collaboration told BBC News on Thursday evening.

"We wanted to find a mistake - trivial mistakes, more complicated mistakes, or nasty effects - and we didn't.

"When you don't find anything, then you say 'well, now I'm forced to go out and ask the community to scrutinise this'."

Friday's meeting was designed to begin this process, with hopes that other scientists will find inconsistencies in the measurements and, hopefully, repeat the experiment elsewhere.

"Despite the large [statistical] significance of this measurement that you have seen and the stability of the analysis, since it has a potentially great impact on physics, this motivates the continuation of our studies in order to find still-unknown systematic effects," Dr Ereditato told the meeting.

"We look forward to independent measurement from other experiments."

Neutrinos come in a number of types, and have recently been seen to switch spontaneously from one type to another. The Cern team prepares a beam of just one type, muon neutrinos, and sends them through the Earth to an underground laboratory at Gran Sasso in Italy to see how many show up as a different type, tau neutrinos.

In the course of doing the experiments, the researchers noticed that the particles showed up 60 billionths of a second earlier than they would have done if they had travelled at the speed of light. This is a tiny fractional change - just 20 parts in a million - but one that occurs consistently.

The team measured the travel times of neutrino bunches some 16,000 times, and have reached a level of statistical significance that in scientific circles would count as a formal discovery. But the group understands that what are known as "systematic errors" could easily make an erroneous result look like a breaking of the ultimate speed limit. That has motivated them to publish their measurements.

"My dream would be that another, independent experiment finds the same thing - then I would be relieved," Dr Ereditato told BBC News.

But for now, he explained, "we are not claiming things, we want just to be helped by the community in understanding our crazy result - because it is crazy".

Story taken from BBC News (The link below includes pictures that help explain it better)
http://www.bbc.co.uk/news/science-environment-15017484


Quote:
What if particles really can exceed the speed of light?

It is a fascinating and provocative question. But first, it should be said that Thursday's news that physicists have seen subatomic particles called neutrinos exceed the Universe's speed limit is a picture of science still at work.

The researchers at Cern in Switzerland and Gran Sasso in Italy have tried really hard to find what they might be doing wrong - over three years and thousands of experiments - because they can hardly believe what they are seeing.

The publication of their results is a call for help to pick holes in their methods, and save physics as we now know it.

"The scientists are right to be extremely cautious about interpreting these findings," said Jim Al-Khalili, a physicist from the University of Surrey, who suggested that a simple error in the measurement is probably the source of all the fuss.

But he has gone further.

"So let me put my money where my mouth is: if the Cern experiment proves to be correct and neutrinos have broken the speed of light, I will eat my boxer shorts on live TV."

Let us be clear: it would be a tremendously exciting time for physics, and a daunting one for physicists, but it is not going to change the price of milk.

Perhaps the most exciting thing is that time travel would look more feasible.

The speed of light is the cornerstone in Einstein's theory of special relativity, which is what gives us the concept of causality: causes precede effects, wherever you are. Remove that requirement, and time becomes a much more fluid thing than the one-way arrow we think it to be. If an effect can precede a cause, showers of neutrons might arrive here on Earth before a supernova actually kicks off on the other side of the galaxy.

OK, here's what we really want: Back to the Future-style popping around in time might be within our reach.

It gets weirder. Einstein may not have been wrong if we concede that there are extra dimensions of space that particles can nip into and out of, and some theories have already been around a while that suggest it.

"They're not mainstream theories, but they're fine," Brian Cox, a physicist who has worked at Cern, told the BBC.

"Let's say you go from London to Sydney - you fly around the Earth," Prof Cox explained. "The other way to do it is to go through by digging a big tunnel straight through the Earth, and that's the shortcut.

"In some ways, extra dimensions can behave like that and ... the neutrinos could be taking a shortcut through another dimension."

That leads neatly on to the "wormholes" popularised in science fiction, connecting one place in space to another vastly distant one. The list goes on - and there is a host of other implications, most of which arise because the speed of light figures in so many equations in science. It holds all of quantum mechanics together, for example, and that has given us the modern era of electronics, the internet, and the gizmo on which you are reading this.

Get an information-carrying particle going faster than light, and you change computing altogether. How about solving tomorrow's problems today?

This, again, is all speculation. But even Cern's director of research Sergio Bertolucci briefly got into the game.

"We all like the idea of travel in time, but it would be very difficult," he told the BBC.

"You can imagine: we'll never get old - politicians would stay young forever."

But Antonio Ereditato, part of the Opera collaboration that found the curious result, is holding fire on what it all might mean if true.

"I would prefer not to elaborate on that," he said.

"I'm sure that there are many, many colleagues in our community who will start to elaborate, but our task for the moment is one step behind: to make sure - absolutely sure - that this is a real effect and as solid as we think.

"But this must be confirmed by other colleagues. This is the way our work is done."

Second story also taken from BBC News.
http://www.bbc.co.uk/news/science-environment-15034414

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24 Sep 2011, 09:08
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Don't bother with that, as it's 99.99999999% wrong. The reasons mainly four:
1) They used GPS for timing the time-of-flight of the neutrinos. Light doesn't travel at the speed of light in the air and they didn't account for that.

2) GPS does not have the accuracy needed for this experiment ~1ns (=1/10^9 seconds).

3) The neutrinos were created at CERN in Geneva and detected in Italy. The creation of the neutrinos cannot be timed exactly (as it is done with other particles) as neutrinos interact ***very*** weakly with matter (they have no charge and are nearly massless). Thus there is large uncertainty in the timing of the detection.

4) The neutrinos have to travel underground, through the Earth's crust and obviously that distance cannot be measured to micrometer accuracy. The quoted accuracy needed for this would be on the order of a few meters though but I don't believe they have that either (i will check the paper more closely).

This is my assessment of the results as a professional physicist (and relativist) and actually most of the people I have spoken to at my physics department agree with these reasons. I would be very surprised if the results withstand honest scientific scrutiny. In any case relativity has been tested in thousands of experiments (including ones with neutrinos) and has been confirmed again and again. A well respected physicist (Sean Carroll) goes into some more depth in this blog: http://blogs.discovermagazine.com/cosmi ... neutrinos/

Unfortunately, I have to mention one (possible) fifth reason for this, and that's called "over-hyping your results in order to get more funding next year". I don't know the people of the collaboration to say if this is the case but it has been done before. :redface:

So, unless these questions are answered and the experiment is duplicated by other independent teams around the world, I would say that Relativity is safe. :cool:

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26 Sep 2011, 12:17
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