back to article Neutrinos still FASTER THAN LIGHT in second test

The boffins who sent sub-atomic particles on a faster-than-light journey into the past have done another successful experiment that confirms the results. In the original test, 15,000 beams of neutrinos were fired over three years from CERN near Geneva 720km to Gran Sasso in Italy and the particles arrived at their destination …

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Facepalm

Yea, I heard that about a dozen times by now (thanks, LFMF), but nobody bothers to post the spanish word for 'embarassed', 'avergonzado'

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Anonymous Coward

All very interesting.

Still, my money is on experimental error. I mean, its not like the discrepancy is huge.

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Joke

OPERA Users

Just gotta be faster than the rest of us, don't they?

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In the office

I laughed out loud.

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Happy

I think Arthur C Clarke covered this ...

If a respected scientist claims something is possible, he is very probably right.

If a respected scientist claims something is *impossible* he is very probably wrong.

Am I alone in seeing this as just another rung on the ladder ? We went from Aristotle to Newton, Newton to Einstein, and now Einstein to beyond ?

Or is there some absolute somewhere I missed ?

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Anonymous Coward

Have they tried firing them in the opposite direction to see if those take longer ... its pretty obvious from looking at a map that at the moment they are firing them downhill so its not surprising if they pick up a little extra speed!

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Silver badge

"Have they tried firing them in the opposite direction"

I don't think anyone wants to build another CERN accelerator in Italy unless it's absolutely necessary.

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Distance over time

What i want to know is how they have managed to accurately measure the distance between CERN and Italy. Surely the whole thing despends on accurate distance divided by accurate time. The timing I can understand but the accurate distance seems to be the difficult item. I would double check the ruler if it was me.

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One would think they checked carefully using acceptable techniques. After all, they're expecting to measure to the nanosecond, so everything would have to be calibrated carefully and accurately to give any credence to the results.

Of cause, what should happen now is the test needs running elsewhere and confirming. Unfortunately the only place I can think where there might be a facility capable of running the same tests would be in the US.

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Hilarious

Some of the commenters here seem to think CERN are timing these experiments with wind-up alarm clocks and measuring the distance with string...

60ns at light speed is about 17m from memory. Your hand-held GPS is already an order of magnitude more accurate than that.

Oh and as no one else has said it so far, I will. They're firing these neutrinos through solid rock, which is why they're not measuring light. Because rock will stop light. As well as beating scissors.

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Unhappy

yes - it has been mentioned

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Trollface

Measure the distance

Easy, they fired a photon and timed it

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This post has been deleted by its author

Scientific Papers

The paper at arXiv (see article link) has, unsurprisingly, a huge section on the "method". Section 4 discusses measuring the distance.

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Anonymous Coward

Could they not perhaps just set up a two-directional flow, and wire the emitters to the detectors, so as soon as one end detects a neutrino pulse, it could send one back? And after a few billion back-and-forth bounces the cumulative time difference should have added up to something measurable?

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Umm...

You don't have huge accelerators on both ends...

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Neutrinos don't really react very well with other matter, that's why they are ably to pass straight through the Earth. You can't bounce them back as you have nothing that will act as a reflector. If your idea was to send another separate neutrino back to CERN each time the detector detected a neutrino then this factors in a lot more uncertainty about timing and would also require another Large Hadron Collider to be built under the Italian Alps.

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IANAPP*

I'd guess that between the sensor, whatever components inbetween and the retransmission equipment, component tolerances might get in the way a bit.

*Particle Physicist

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Thing is you need to build a particle accelerator over in Italy as well then - and those are neither small nor cheap.

In addition, the neutrino pulses can only be created when you whack a "bunch" of protons from the ring into the neutrino-makery-thingy - the beam isn't constant, so you'd have to wait until a bunch is in the right place on the ring, and you'd have some even more fun errors taking into account the time for the system to react to the incoming signal and the time for the bunch to reach the target to be neutrino-ised.

Also, not quite sure what this would achieve anyway, other than showing that the effect happens both ways, rather than in only one!

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Anonymous Coward

No they didn't

That's all I have.

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Anonymous Coward

Sound thru a solid

OK, at the risk of looking really stupid... Am I right in thinking that sound goes faster thru a solid that it does through air? I know that the speed of light measure is through a vacuum... So, you can't send light through a solid BUT could it be that we're seeing how fast light is through a solid (mountain)??

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Actually one possible explanation is that neutrinos interact with the matter (I know that the cross section is very very small, but we still don't have lot of data about neutrinos' physics) and it's like sound through rock or light through plasma

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Coat

Hmmm...

Why not ask my wife?

After all, she has an answer for f'cking everything!

(C) 1976 Bernard Manning.

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Stop

Easily solved...

As CERN is higher in altitude than Gran Sasso then it follows that the Neutrinos are travelling downhill faster than the light.

Or something scientific like that.

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Boffin

Low-down stuff and everything

Say no to crazed speculation and wannabe and has-beens and angry yoofs and yes to boring details. Take a gander:

http://www.science20.com/quantum_diaries_survivor/opera_confirms_neutrinos_travel_faster_light-84763

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Stop

why?

why do so many people not actually research the topic on which they are commenting before posting?

Just asking.

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I reckon the ones that chose to do that....

...are still busy researching. As soon as I started looking at the subject I reaslised just how much there is to learn. I may feel qualified to comment in say three of four years.

Maybe.

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Anonymous Coward

Eh?

err... why does FTL = backwards in time? A fanciful notion but impossible, the Universe forbids it.

The concept of Time, usually labeled as a "dimension" is, therefore, the FIRST dimension, not the FOURTH.

There is, and always will be in any dimension you care to theorise or imagine, always Time and always flowing toward the future, or forward as you may conceive it.

So give up those romantic dreams of travelling backwards in Time, you cannot.

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FTL => backwards in time

Relativity, as far as measured/observed sub-light speeds, fits the theoretical equation that implies time-reversal (or at least breaking causality) when v > c (look up "tachyonic antitelephone").

But of course it is not known if the theory holds outside of our experience, and thus if faster than light *is* capable of time-reversal.

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General relativity permits time travel in certain extreme circumstances. It is (theoretically) possible to travel along a space-like path around a rapidly spinning black hole* that would allow you to return to your starting point before you set off. Most likely, this indicates that relativity breaks down near black holes. But anyone who's taken relevant undergraduate physics classes will be aware that relativity and quantum mechanics are incompatible - even though they have both passed every experimental test we have been able to construct.

* a stellar-mass black hole won't work, the tidal effects would destroy any physical object trying to follow such a path. It could be possible with a galactic-mass black hole, but they are not likely to spin sufficiently rapidly.

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Paris Hilton

Told you so

Of course, the apparent discrepancy in the measurements will get bigger as the end of the Mayan calendar draws closer...

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Mushroom

fast?

Who says that the speed of light is the ultimate speed? its just the fastest thing know to man currently. The test at cern shows that its possible to go faster so im not sure why everyone is saying it can't be done.

I have watched many sciencey programs that says the big bang happened everywhere at the same time, well since space is a bit of a big area it would take something pretty damn fast to get across the universe in an instant.

my theory on the neutrinos is simply they are so small they can pass though other atoms and photons whereas light gets bounced around other atoms on the same journey, eg, straight line as apposed to a wibbly wobbly one

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Boffin

DUH!!!

Way to look like a complete idiot, I suggest you at least get a grasp of GCSE level physics before joining a thread like this again.

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You're not Stephen Fry are you?

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reminds me...

... of the premis from the book TimeScape ...

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a thought...

... has this been approved by the Chinese government?

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Anonymous Coward

Surely this should be settled by another group of scientists?

Wouldn't that be the easiest way to see whether OPERA have some sort of systemic error?

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Headmaster

OK, in answer to those questions...

1) they can't send light alongside the neutrino beam because it'd mean digging a very long tunnel, which costs £££. The neutrinos go through the rock quite happily but light wouldn't play ball.

2) they can't send a beam back the opposite direction because generating a neutrino beam requires a huge accelerator a) which costs £££ and b) isn't very practical a mile underground

3) even if they had an accelerator in Gran Sasso and OPERA II in Geneva and decided to play neutrino tennis, it takes too long to prepare and fire an intense beam of protons to produce the neutrino beam. They couldn't do it so many times per second with current tech.

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Is this really new?

From what I have read in the past, is this really a surprise? Do we not normally detect Neutrons on the earth as a result of the super nova before we actually detect the light bursts?

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Re : Is this really new?

That's because light interacts strongly with matter so takes some time to escape from the super nova whereas neutrinos don't so set off first at almost c.

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No, we don't. Neutrinos from 1987's supernova arrived just at the precise time on which they were expected if they were travelling at c. They arrived 3 hours before the light just because they were emitted 3 hours before the light, being the light emitted only when the shock wave reaches the exterior of the star

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Anonymous Coward

As Agent Kay (kind of) said

"Fifteen hundred years ago everybody knew the Earth was the center of the universe. Five hundred years ago, everybody knew the Earth was flat, and fifteen minutes ago, you knew that the speed of light was the limit. Imagine what you'll know tomorrow."

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How many more times...

"Five hundred years ago, everybody knew the Earth was flat"

Almost everyone who THOUGHT about it didn't think it was flat. Most people weren't bothered either way. Sailors and anyone living near the coast knew if wasn't flat, ships would slowly 'sink' below the horizon and then come back

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Holmes

How About:

ok so light is 'Fast' and supposidly the fastest speed there is.

what if we think about temprature for a second.

in the universe absolute Zero is cold, but the coldest (un man made) temp is slightly warmer by a degree or so (thanks QI), so absolute Zero is slightly colder than the universes 'natural' lowest tempriture.

if you apply that logic to light, maybe light itself is ever so slightly slower than the speed of light (lets say 'top speed'), so going faster than light is possible, BUT faster than 'top speed' is not, so all the stuff/physics is correct, they are just asuming that the speed of light and top speed are the same thing.

see what i mean..?

(but what do i know)

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Anonymous Coward

Sounds like a good point, so redefine c to be "speed of neutrinos in a vacuum".

Pity that a "Faster Than Neutrino" drive", or "I'm making the jump to neutrino-speed" all sound a bit lame.

I vote we rename wimpy neutrinos to something manly like "zapprons".

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It's worth watching the last 25 mins of that BBC programme Marcus du Satoy did about this in the last month or so.

This second expt has ruled out one of the possible causes. But who knows about whether the earth's density is accurately known enough along this path for that not to cause some GR fluctuations or something else that clearly isn't obvious.

Anyway, the the du Satoy programme said, if this is right then a prior experiment which recorded neutrinos and light arriving at the same time from a supernova must have some massive error or effect as I think it would have meant the neutrinos should have arrived 25yrs before the light.

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Go

Race 2 particles

Why don't they race a neutrino and another particle that definitely does go at light speed and see which arrives at the destination first.

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Anonymous Coward

There is no problem going faster than light. The problem is that if you have mass you can't accelerate to the speed of light in order to pass it. The maths tells you so. So conjecture on a top speed being > light speed doesn't solve anything. If this neutrino result is upheld and if we believe neutrinos have mass, then the theory may need modifying.

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Anonymous Coward

"faster-than-light journey into the past "

No, something going faster than the speed of light does not equate to going back in time, however or whenever you observe it.

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Anonymous Coward

Current maths and theory says the speed of light in a vacuum is the max and that nothing can go faster than it. Experiments show light through other mediums can travel considerably slower, e.g. through sodium.

Fine, except current maths and theories has been updated and proved incorrect time and time again over the years. We just need to find another particle that travels faster. Maybe we have already.

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