This article is from the source 'bbc' and was first published or seen on . It last changed over 40 days ago and won't be checked again for changes.

You can find the current article at its original source at http://www.bbc.co.uk/go/rss/int/news/-/news/science-environment-15017484

The article has changed 12 times. There is an RSS feed of changes available.

Version 0 Version 1
Speed-of-light experiments yield baffling result at LHC Speed-of-light experiments yield baffling result at LHC
(40 minutes later)
By Jason Palmer Science and technology reporter, BBC NewsBy Jason Palmer Science and technology reporter, BBC News
Puzzling results from Cern, home of the LHC, have confounded physicists - because it appears subatomic particles have exceeded the speed of light.Puzzling results from Cern, home of the LHC, have confounded physicists - because it appears subatomic particles have exceeded the speed of light.
Neutrinos sent through the ground from Cern toward the Gran Sasso laboratory 732km away seemed to show up a few billionths of a second early. Neutrinos sent through the ground from Cern toward the Gran Sasso laboratory 732km away seemed to show up a tiny fraction of a second early.
The results will soon be online to draw closer scrutiny to a result that, if true, would upend a century of physics. A report will soon be online to draw closer scrutiny to a result that, if true, would upend a century of physics.
The lab's research director called it "an apparently unbelievable result". In the meantime, the group says it is being very cautious about its claims.
The speed of light is the Universe's ultimate speed limit, and the entirety of modern physics - as laid out in part by Albert Einstein in his theory of relativity - depends on the idea that nothing can exceed it. "We tried to find all possible explanations for this," said report author Antonio Ereditato of href="http://operaweb.lngs.infn.it" >the Opera collaboration.
"We wanted to find a mistake - trivial mistakes, more complicated mistakes, or nasty effects - and we didn't," he told BBC News.
"When you don't find anything, then you say 'Well, now I'm forced to go out and ask the community to scrutinise this.'"
Caught speeding?
The speed of light is the Universe's ultimate speed limit, and much of modern physics - as laid out in part by Albert Einstein in his theory of 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.Thousands of experiments have been undertaken to measure it ever more precisely, and no result has ever spotted a particle breaking the limit.
But Antonio Ereditato of href="http://operaweb.lngs.infn.it" >the Opera collaboration and his colleagues have been carrying out an experiment for the last three years that seems to suggest neutrinos have done just that. But Dr Ereditato and his colleagues have been carrying out an experiment for the last three years that seems to suggest neutrinos have done just that.
Neutrinos come in a number of types, and have recently been seen to switch spontaneously from one type to another.Neutrinos come in a number of types, and have recently been seen to switch spontaneously from one type to another.
Dr Ereditato and his colleagues prepare a beam of just one type, muon neutrinos, sending them from Cern to an underground laboratory at Gran Sasso in Italy to see how many show up as a different type, tau neutrinos. The team prepares a beam of just one type, muon neutrinos, sending them from Cern 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 sooner than light would over the same distance. In the course of doing the experiments, the researchers noticed that the particles showed up a few billionths of a second sooner than light would over the same distance.
The team measured the travel times of neutrino bunches some 15,000 times, and have reached a level of statistical significance that in scientific circles would count as a formal discovery.The team measured the travel times of neutrino bunches some 15,000 times, and have reached a level of statistical significance that in scientific circles would count as a formal discovery.
But because the result is so unexpected and would wreak such havoc with our understanding of the Universe, the group is being particularly cautious. They have opted to put a report their measurements online to subject them to wider scrutiny, and will hold a seminar at Cern on Friday to discuss the result. 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, and 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 said.
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".
"And of course the consequences can be very serious."