Speed-of-light results under scrutiny at Cern

Opera detector Enormous underground detectors are needed to catch neutrinos, that are so elusive as to be dubbed "ghost particles"

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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 has published its work so other scientists can determine if the approach contains any mistakes.

If it does not, one of the pillars of modern science may 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.

Start Quote

We want to be helped by the community in understanding our crazy result - because it is crazy”

End Quote Antonio Ereditato Opera collaboration

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."

Graphic of the Opera experiment

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".


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  • rate this

    Comment number 125.


    I blame EU regulations! Or is it 'God' playing around? , Maybe the Particles are evolving, as predicted by Darwin.
    Lets have some more stupid ideas from out there.
    Or we could accept that as untrained readers the story is of interest but we do not have the knowledge to make valued comments.
    (or is it the Klingons?)


    Great point

  • rate this

    Comment number 124.

    This doesn't surprise me at all. I witnessed something in 1990 that appeared to be very much faster than the speed of light. It looked like a sattelite to the naked eye, but was moving from star to star, then changing direction at each star, continueing on to the next star and the next after that. The time elapsed travelling between stars was appr. 10-15 secs. Do the maths and it seems impossible?

  • rate this

    Comment number 123.

    This reminds me of asituation when a peasant came to the zoo and for the first time in his life saw a camel. He stood and watched and studied the creature when finally, losing his patience, left mumbling "this is absolutely impossible".

  • rate this

    Comment number 122.

    If I were them, I would be checking out my time synchronisation arrangements. Are the particles early because the receiver clock is fast?

    Also, presumably, there is an analogue to refractive index for the particles moving through the ground; have they just found a new gas field?

  • rate this

    Comment number 121.

    Of course Einsteins Theories were incomplete - is why people are still researching it.

    Relativity and special relativity have stood up to scrutiny exceptionally well so far though.

    Personally I think there must have been some mistake. Neutrinos have a rest mass. Nothing that does not have zero rest mass can go the speed of light. Doesn't make sense. Is illogical captain!

  • rate this

    Comment number 120.

    Science is restricted by the human mind and it's universally agreed that we don't use the whole of our capacity (some less than others?). I suspect there are "little green men" laughing themselves silly about how advanced the human race thinks it is when there's a good chance we're "light years" behind races that we don't have the capcity to understand let alone see.

  • rate this

    Comment number 119.

    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 special THEORY of relativity - depends on the idea that nothing can exceed it. The uperative word is theory. It is only true until it is disproved then another THEORY is developed which meets what is known. So they may need to go back to basics.

  • rate this

    Comment number 118.

    In order to check their readings, they should put another camera half way along the pathway. If they also painted it yellow, I am sure that they would then see them all slow back down to the correct speed.

  • rate this

    Comment number 117.

    Whilst the calculations of how long it should take light and therefore nuetrinos to reach the destination are accurate, I still think its a shame that due to the nature of the experiment they can not send some photon's down the same route...perhaps they would get the same result with photons and a stronger indication of why this is happening.

    Or perhaps the universe is contracting after!

  • rate this

    Comment number 116.

    So how exactly did Einstein come up with that speed of light limit? Is this something deducted from his theories or it's a supposition the whole corpus of relativity is build upon? In other words, the fact that the speed of light is the limit, is a dogma or there is a rationale behind it?

  • rate this

    Comment number 115.

    If true,it could explain why some particles appear to be in 2 places at once - the particle gets from a to b before the light leaves from a. Something I've been thinking about for a long time.

  • rate this

    Comment number 114.

    I agree with Phil at 99 but I wouldn't say 'wrong' is the right word. I think their work was correct as far as their understanding could be. But yeah all scientific enlightenment is only a stepping stone to further enlightenment down the line. It all become obsolete in the end... I don't think it makes it any less significant.

    And I agree that congratulations are in order

  • rate this

    Comment number 113.

    The more success the quantum theory has, the sillier it looks - Albert Einstein.

    And just how are we going to use this new found fact, if it is fact and not just a fly, bit of dust in the mechanism etc?

    One day someone is going to run one of these tests and turn a large part, if not all of the world inside out because they are going to split something!

    A bit Pinky & The Brain in context?

  • rate this

    Comment number 112.

    Maybe I'm naive but to claim that there is a limit to speed seems a bit arrogant and narrow minded. I do hesistate to use such words as the scientists at Cern are clearly highly intelligent and learned people. Yet, In the words of daft punk, surely everything can become harder, better, faster, stronger?

  • rate this

    Comment number 111.

    Looks like some peoples grasp of physics is as good as their maths.
    If neutrinos arrive in Italy a few billionths quicker, this would signifigantly get larger at further distances ie light years!

  • rate this

    Comment number 110.

    I find it incredible that Einstein predicted so much so accurately, overturning Newton's era (or, at least greatly increasing our understanding). This experiment does seem to counter the results of a great deal of experiments that have been done to date. I can't help but be skeptical, but greatly appreciate the Scientists' claims and their more 'baffled' rather than triumphant comments.

  • rate this

    Comment number 109.

    Neutrinos are quick but they aren’t a patch on the Chav particle, this particle regularly exceeds the speed of light when the Benefit Office opens up or Lidls have a 2 for 1 offer on super strength lager. Even more astonishing are the repel speeds that the particle can reach if the host is offered any form of work. Amazing eh ??

  • rate this

    Comment number 108.

    The results are observed within a 'confidence interval'. That means there're possible errors arising from sample size, measurement artifacts etc. All the scientists are saying is that their expts. are significant within a certain accuracy, and they want an independent review of their results. If one can prove mathematically that a speed above light exists, then you're on to something.

  • rate this

    Comment number 107.

    At the risk of paraphrasing someone more knowledgable than I, maybe they changed the outcome by measuring it?

  • rate this

    Comment number 106.

    I didn't know so many people were experts in physics, and I also didn't realise that their preferred method of refuting a claim is to post a comment on BBC news instead of going to a lab and proving their counter-arguments scientifically!


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