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 265.

    249, I should go to bed, so I'll end on that... time is a dimension, almost exactly like space. Everything, you, me, neutrinos, photons, are traveling through "space-time", a four dimensional "manifold", (timey-wimey space stuff), all four dimensions are related to each other, time is just 'perpendicular'. Imagine sound, your ears measure the time between vibrations, just like eyes measure space.

  • rate this

    Comment number 264.

    "Ye cannae change the laws of physics, Jim!" Of course you can, that's basically what Science is! I have always thought c was a little too neat.

  • rate this

    Comment number 263.

    Is it OK to query global warming science now?

  • rate this

    Comment number 262.

    It does sound like they've incorrectly measured the path length... however I'm sure one of the 10's of scientists working on the project would have thought of that and eliminated any obvious mistakes i.e. GPS errors.

    Perhaps they have observed some form of gravitational waves that are causing space-time to oscillate and thus the path length is contracting periodically???

  • rate this

    Comment number 261.

    This basicly ruins the entire concept of physics! To have a speed greater than the speed of light then the force needed to accellerate to that speed will be infinity! There is no such force!!

  • rate this

    Comment number 260.

    In fact it could just be a space-time geometry not being minkowskian see the research article on Cornell university site, published before the recent discovery. No contradiction with Einstein but a geometry and math complement (stating it simply curved space).
    "Lorentz invariance of the laws of physics does not imply that space-time is indeed minkowskian"

  • rate this

    Comment number 259.

    Add the conclusion from these results to the results of the experimentally proven Bell's Theorem (non locality exists) and it is clear that the Standard Model will eventually join the other discredited 'absolutes' such as the 'ether' the 'flat earth' etc.
    A little humility instead of scientific arrogance would help us all move toward a more open minded position as to what reality really is.

  • rate this

    Comment number 258.

    Am I missing something here ? I don't recall that Einstein or Relativity say that faster-than-light travel is impossible. All that's impossible is for something to travel _AT_ the speed of light. Granted, there are all sorts of knock-on problems with causality etc., and if this result is verified then it'll be really exciting, but theorists have speculated about tachyons for ages.

  • rate this

    Comment number 257.

    This is the crux of science: the best theory must explain ALL verifiable observations with the minimum initial information content - i.e. very few 'laws' or assumption, no magic - plus rigorously provable maths. You then work from that to make predictions, which you test. It is GREAT to have an observation which confounds your expectation. If verified, you must improve/replace the theory. Fun!

  • rate this

    Comment number 256.

    I suspected for years that Einstein was dodgy - his eyes were too close together for a start.
    However I think perhaps it might be an idea to await some further measurements being made before instigating a major panic such as dusting off the writings of Ed Leedskalnin?

  • rate this

    Comment number 255.

    Does anyone know if this means E>mc^2 or E

  • rate this

    Comment number 254.

    Why do people keep referring to E=mCsquared? This equation describes the relationship between mass and energy. If you convert a given amount of mass totally into energy the equation tells you how much you get and vice-versa. It has been proven in billions of experiments and is nothing at all to do with whether particles can travel at the speed of light.

  • rate this

    Comment number 253.

    Science is briliant, but it is subject to paradym shifts; when the framework within which we operate totally changes: as in Newton to Einstein.

    This means it is a belief system based on undcertain assumptions. It also means science can't handle questions beyond how things work; meaning is outside its range.

    So, less statements beginning "We KNOW that..." and more repect for faith pease.

  • rate this

    Comment number 252.

    Theories are just theories until it's proven right or wrong.
    Some of Einstein's theories turned out to be correct, many have been replaced by the likes of Veneziano & Hawking and such whom wouldn't of got their theories without basing it on Einsteins thinking.
    It took 282 to prove Newton's theory of universal gravity, which we did on the moon with a feather and hammer. This is just the beginning

  • rate this

    Comment number 251.

    "bertsprockett It has been observed for decades that nuclear processes can produce particles moving at velocities greater than the speed of light. They then emit energy as blue Cerenkov radiation as they slow down to the speed of light."

    The speed of light in a vacuum cannot be exceeded. Cerenkov radiation comes from particles exceedin the SOL in a medium such as water.

  • rate this

    Comment number 250.

    "the researchers noticed that the particles showed up a few billionths of a second sooner"

    So we know more and more about less and less.

  • rate this

    Comment number 249.

    I heard an idea of a 4th dimension as being time. if time is actually a dimension, then a nutrino travelling within this dimension at a slower speed than light, could actually travel faster then light

  • rate this

    Comment number 248.

    Dear Editor,
    Please explain what on Earth you were thinking when choosing your 'Editors' Picks'?

  • rate this

    Comment number 247.

    [Neutrinos] "They are, however, very difficult to study because they interact so weakly with normal matter. Hence, their nickname - "ghost particles". From an article on BBC news site, 15th June 2011. Maybe the light particles 'photons' are being slowed slightly by normal matter, similar to resistance in an electrical wire increasing as it gets warmer. Whereas neutrinos don't suffer this.

  • rate this

    Comment number 246.

    It would be interesting, if this proves true, to see an analysis of the potential impact. Maybe it will explain where the dark matter is! However I suspect there is something overlooked. Does anyone know how much they are exceeding the speed limit by; 1%, 10%, 1000%?


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