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Author Topic: Did a broken cable produce apparently faster-than-light neutrinos?  (Read 8661 times)

Offline imatfaal

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Preliminary news leaking out on the possibility that a dodgy cable connection was to blame for the anomalous readings

Initial news article here
« Last Edit: 04/03/2012 19:10:50 by chris »


 

Offline CliffordK

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Re: Possible Flaw found in Gran Sasso Results
« Reply #1 on: 23/02/2012 10:29:08 »
Interesting.

Everything indicates that neutrinos travel through space at the same speed as light, although it is possible that it could change speed through different types of matter.

While I am absolutely convinced that there is a speed difference in the one-way speed of light, it is also apparently very difficult to measure.  While they could have measured the one way speed of light, it is apparently not possible to do so using their methods.

And, thus I'm not surprised to read that an error in the measurements may have been found.
 

Offline Soul Surfer

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Re: Possible Flaw found in Gran Sasso Results
« Reply #2 on: 23/02/2012 11:32:56 »
I'm sure that it will make the opera team a lot happier if it was found to be instrumental error.  One of the main reasons they published was to encourage the results to be checked thoroughly although a 60ns error in something like a basic cable connection sounds quite big.  Remember thats around 60ft of space or around 30-40 ft of cable.  we will await confirmation in either direction.
 

Offline imatfaal

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Re: Possible Flaw found in Gran Sasso Results
« Reply #3 on: 23/02/2012 13:51:47 »
Cliff - not sure what you are getting at.  What substances slow down neutrinos?  And how does this have to do with the one way speed of light?  they were not measuring the speed of light at all - best to do that in air or even better space, it was 730km of rock the neutrinos were travelling through and light would have a bit of problem making that journey.  I think they would prefer to think of it as an error in equipment rather than measurement - instrumental error rather than human error.

Soulsurfer - I agree they much prefer instrumental error over the dreaded miscalculation or methodological error; but I think secretly they all prayed that the little buggers were in reality superluminal.

Please bear in mind this is a very speculative article and not at all confirmed
 

Offline simplified

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Re: Possible Flaw found in Gran Sasso Results
« Reply #4 on: 23/02/2012 16:07:29 »
I said experiment with synchronization of clocks on satellite can be more important.However scientists  have chosen wrong way of experimental sequence.
 

Offline imatfaal

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Re: Possible Flaw found in Gran Sasso Results
« Reply #5 on: 23/02/2012 16:35:21 »
Simplified - synchronized clocks on satellites is basically what the GPS system is; and it seems to work very well.  what is it you are looking to prove/disprove?
 

Offline Geezer

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Re: Possible Flaw found in Gran Sasso Results
« Reply #6 on: 23/02/2012 17:59:23 »
I see they are also "investigating an oscillator".
 
Is it a Swiss oscillator, or a cheap Italian knockoff?
 

Offline CliffordK

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Re: Possible Flaw found in Gran Sasso Results
« Reply #7 on: 23/02/2012 20:03:32 »
The point of the experiment is that they don't know how neutrinos behave in rock.  Sound travels faster though solid matter, but light travels slower.

Their beam is only in a single direction, so technically it is at least related to the one-ways speed of light, but that brings up serious clock synchronization issues.
 

Offline imatfaal

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Re: Possible Flaw found in Gran Sasso Results
« Reply #8 on: 24/02/2012 09:43:02 »
The point of the experiment is that they don't know how neutrinos behave in rock.  Sound travels faster though solid matter, but light travels slower.
  Yes they do know.  The neutrinos that arrive in Gran Sasso have not interacted with anything - otherwise they would not be there.  They have travelled at exactly the same speed as they would in the vacuum.   

Quote
Their beam is only in a single direction, so technically it is at least related to the one-ways speed of light, but that brings up serious clock synchronization issues.
  This would be only pertinent if light speed was not the same in all inertial frames - but it is invariant, so it is a complete red herring.  The theory behind the clocks and synchronisation was fine - it seems that one of machines was not up to scratch and/or another lead was incorrectly plugged in
 

Offline imatfaal

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Re: Possible Flaw found in Gran Sasso Results
« Reply #9 on: 24/02/2012 09:48:32 »
I see they are also "investigating an oscillator".
 
Is it a Swiss oscillator, or a cheap Italian knockoff?

It was probably a very expensive Swiss Oscillator that someone had bought from a friendly guy in a market in Singapore. 

I bought a knock-off submariner as a callow youth - and it was practically indistinguishable in looks from my bosses kosher version (whilst costing several hundred times less); but its time keeping was rubbish, one of the little spots that mark the hour came loose, and when I went swimming it filled with water - apart from that it was fine.
 

Offline simplified

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Re: Possible Flaw found in Gran Sasso Results
« Reply #10 on: 24/02/2012 19:17:42 »
Simplified - synchronized clocks on satellites is basically what the GPS system is; and it seems to work very well.  what is it you are looking to prove/disprove?
We should  just check the work of relativity in inertial system of a satellite(rest of a clock on the Earth looks like a travel relatively of satellite)Don't forget that synchronization of both clocks mast be local ,and the local place is the satellite in the inertial system of satellite!Both clocks should be on the satellite at times of the synchronizations.Don't confuse different things.
« Last Edit: 24/02/2012 19:22:46 by simplified »
 

Offline simplified

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Re: Possible Flaw found in Gran Sasso Results
« Reply #11 on: 25/02/2012 05:00:29 »
I confused something.We should synchronize clocks at start of the experiment.At finish of the experiment we should observe distinction of two clocks on satellite.
 

Offline greeniemax

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Re: Possible Flaw found in Gran Sasso Results
« Reply #12 on: 25/02/2012 09:08:29 »
The flaw in the experiment is getting more attention than the actual results, in case the flaw isn't right and everything seems to me okay it'll be a big problem its like back to the drawing board for most of the science.

The error range and the actual tested speed is quiet big and I don't think could be resolved by single cable problem otherwise many experiments done will have same issue of making sure that we have the right values, probably most of the experiments have to be done again.
 

Offline imatfaal

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Re: Possible Flaw found in Gran Sasso Results
« Reply #13 on: 27/02/2012 13:20:27 »
The flaw in the experiment is getting more attention than the actual results, in case the flaw isn't right and everything seems to me okay it'll be a big problem its like back to the drawing board for most of the science.

The error range and the actual tested speed is quiet big and I don't think could be resolved by single cable problem otherwise many experiments done will have same issue of making sure that we have the right values, probably most of the experiments have to be done again.

Not really Greenie - the experiment (before someone noticed the travel time anomaly) was to do with the oscillation between the different flavours of neutrino and I didn't think the travel time was that much of a crucial aspect.  The neutrinos at Cern were mu-neutrinos (there is a discussion here) and the experiment was interested to see the proportions of electron/mu/tau neutrinos measured at Gran Sasso (I think)
 

Offline yor_on

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Re: Possible Flaw found in Gran Sasso Results
« Reply #14 on: 04/03/2012 18:26:58 »
Thanks Imatfaal. To introduce FTL would create a lot of logical contradictions in Relativity as I think of it.
==

And as mathematics is about logic? Where would that leave it?
 

Offline imatfaal

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Thanks Imatfaal. To introduce FTL would create a lot of logical contradictions in Relativity as I think of it.
==
And as mathematics is about logic? Where would that leave it?

The problem would be in causality - if information can travel faster than light (whether on the back of a neutrino or otherways) then you have a problem with either SR or with causality.   As we would almost certainly agree that causality is sacrosanct, then SR is wrong.  The maths of SR is self-contained, self-consistent, and exact; so there is no possibility of a problem there.  All that remains is that one of two axiomata are incorrect ie SR can only be wrong in an axiomatic sense.   HOWEVER, I am pretty sure we do not have super-luminal transfer of information, thus causality and SR are no put into opposition, and we can all rest easy.
 

Offline wolfekeeper

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While I am absolutely convinced that there is a speed difference in the one-way speed of light, it is also apparently very difficult to measure.  While they could have measured the one way speed of light, it is apparently not possible to do so using their methods.
Light goes the same speed in all directions.

If light went different speeds in different directions, it would be easily shown by measuring distances; if some light was going at an angle to the Earth's motion measured against an ether you would get very different distances in one direction than another.

That's basically how the Michelson-Morley experiment worked.
« Last Edit: 05/03/2012 17:38:41 by wolfekeeper »
 

Offline Ęthelwulf

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Thanks Imatfaal. To introduce FTL would create a lot of logical contradictions in Relativity as I think of it.
==
And as mathematics is about logic? Where would that leave it?

The problem would be in causality - if information can travel faster than light (whether on the back of a neutrino or otherways) then you have a problem with either SR or with causality.   As we would almost certainly agree that causality is sacrosanct, then SR is wrong.  The maths of SR is self-contained, self-consistent, and exact; so there is no possibility of a problem there.  All that remains is that one of two axiomata are incorrect ie SR can only be wrong in an axiomatic sense.   HOWEVER, I am pretty sure we do not have super-luminal transfer of information, thus causality and SR are no put into opposition, and we can all rest easy.

Some reinterpretation rules can modify the equations so they do not violate causality - usually the causality breakdown comes from oscillating in time, so one could use a completely spatial interpretation, for instance.
 

Offline Ęthelwulf

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As Sheldon has remarked saying ''no one is saying that faster than light neutrino's cannot exist.''

This is true, it was just such a hard experiment to reconcile. Nothing has been determined yet. And this talk about the neutrino moving faster in rock, I think that was speculated due to a special refraction index but nothing has been determined there either.

I hope the particles turned out to be superluminal. I wrote an entire mathematical theory for them - shame to see it go to waste.
 

Offline wolfekeeper

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The existing framework and experiments set hard limits on the kind of superluminal movement allowed.

If neutrinos are superluminal, they'd better have a preferred frame of reference, otherwise it's going to be possible to violate causality.

I mean the Lorentz-Fitzgerald transformations have an absolutely vast amount of support, and a superluminal transfer allows those transformations to give you backwards in time communication if the superluminal transfer doesn't have that property.
 

Offline lightarrow

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While I am absolutely convinced that there is a speed difference in the one-way speed of light, it is also apparently very difficult to measure.  While they could have measured the one way speed of light, it is apparently not possible to do so using their methods.
Light goes the same speed in all directions.

If light went different speeds in different directions, it would be easily shown by measuring distances; if some light was going at an angle to the Earth's motion measured against an ether you would get very different distances in one direction than another.

That's basically how the Michelson-Morley experiment worked.
Yes, but what CliffordK intended to say is something that is not well specified in relativity: every time we talk about the speed of light in one direction ("direction" is one of the infinite straight lines passing by the origine, with arbitrary angle) we always intend "go and return" speed: the one-way speed of light is not measurable with standard techniques (and I don't know if it's possible at all and, in case, how).
« Last Edit: 12/03/2012 23:08:19 by lightarrow »
 

Offline yor_on

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I don't think it is possible Lightarrow. A 'one way measure' of the speed of light seems more and more like a pipe-dream :) Although I wondered abut it recently.
 

Offline wolfekeeper

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Nope.

In relativity, the one way and two way and three way and... speed of light in a vacuum is the same in all directions at all times.

You can synchronise clocks, and slowly separate them, and then measure the one-way speed of light.
 

Offline lightarrow

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Nope.

In relativity, the one way and two way and three way and... speed of light in a vacuum is the same in all directions at all times.

You can synchronise clocks, and slowly separate them, and then measure the one-way speed of light.
The problem is that, whatever way you use to synchronise clocks, you have to use the speed of light (or the method used, even the slow transport of physical clocks, is equivalent to using a light signal for synchronisation).
http://plato.stanford.edu/entries/spacetime-convensimul/#3

http://en.wikipedia.org/wiki/One-way_speed_of_light
« Last Edit: 13/03/2012 16:12:29 by lightarrow »
 

Offline wolfekeeper

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I wondered if you'd argue that.

In that case, if you think that nature is conspiring to make it impossible to distinguish the one way speed of light from the two way, then it's completely equivalent to the speed of light being the same in all directions.
« Last Edit: 13/03/2012 16:16:53 by wolfekeeper »
 

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