Big story ....CERN scientists break the speed of light

krd · 21-11-2011 3:16am

shizz wrote: »

From my understanding the Doppler effect isn't relative in the same way time is.

It's cause by the moving source producing sound waves closer at each successive stage because the source is moving in the direction of the waves travel.

No, the source is not producing sound waves that are closer together at each successive stage. Relative to the source, if the source maintains the same velocity and direction, the wavelength of the sound waves will remain constant.

Think of it another way. If you were a person on a train. And sound source was in a stationary position somewhere outside the train. As you approached the source, the tone would appear higher - as you passed it the tone would drop.
The source does not know that you are approaching or receding, the waves don't know either.

It's actually counter intuitive.

The Doppler effect is how a wave appears to the observer.

And it happens with light too. If a star is moving away from you, or think of it another way, the star is not moving, and you are flying away from the star. Your velocity relative to the light from the star will effect how see the wavelength of the light. The wavelength will appear longer.

It's really counter intuitive. If the wave length from a star was 1 metre. then if the star was moving away quickly enough - the wavelength could appear to us as 2 metres. But as far as the photon is concerned the wavelength is 1 metre.

We can still see the light from the big bang, 13 billion years ago. And can calculate the time of the big bang by how stretch out the wavelength has become.

Another way to see how it differs from relativity is, if something was moving a lot faster than you and you could observe someone within that object that was moving that fast, you would see them move a lot slower within it as time for them has slowed down. (obviously exaggerated) But as they move towards you and move away you won't notice any change in how slow they are moving, unless the object slowed down. At least this is how I understand it so Im open to corrections.

I've never liked that example. As it doesn't actually explain anything.

If people were on a spaceship, and having a party, if you could always see them. If they accelerated away from you, as they travelled faster, they would first become reddish looking, then eventually, they would become invisible, the light would be radio waves. I don't know if that would mean, it would appear their motions are slower.

Curly Judge · 21-11-2011 11:39am

The Doppler effect explains the symptoms of sound wave behavior in a source approaching or departing from you at speed.
It is purely a symptom and has no effect on how the source emits the sound wave signal, any more than a high temperature has an effect on how a flu starts.
Ditto with the red shift!
Therefore to say that the red shift is a relativistic phenomenon is probably correct but it is not relativistic per se.
I think?

krd · 21-11-2011 12:35pm

Curly Judge wrote: »

The Doppler effect explains the symptoms of sound wave behavior in a source approaching or departing from you at speed.
It is purely a symptom and has no effect on how the source emits the sound wave signal, any more than a high temperature has an effect on how a flu starts.
Ditto with the red shift!
Therefore to say that the red shift is a relativistic phenomenon is probably correct but it is not relativistic per se.
I think?

See, this relativity stuff is confusing.

There is an evolution to the theory of relativity; Galilean relativity, Newtonian relativity, then Einstein's relativity. Einstein builds on the previous ideas. I'm slowly hacking away at Einstein's stuff - where it gets a little more tricky.

Anyway, what I've been talking about is actually called the Relativistic Doppler effect. Time dilation does occur.

http://en.wikipedia.org/wiki/Relativistic_Doppler_effect

If you're not confused, you don't understand it.

See, how you intuit the world. The whole world appears as if time is the same everywhere, and space is the same everywhere - when it just isn't.

Like my school physics teacher had to believe that the Doppler effect, with sound, was to do with the air resisting the sound wave. Of course, this meant the equations in the school book didn't make sense - but just memorise them and do the exam - their devilry is beyond you. Once you grasp what's really happening, it's actually disturbing; space and time are not absolute as they appear.

It's funny, people were still clinging to an idea like the Aether up until nearly the 20th century.

roosh · 22-11-2011 12:39pm

Rejection of FTL neurtino result

The rejection of the claim is based on the expectation that the neutrinos should have lost discernable amounts of energy, had they travelled faster than light. Just wondering, is this expectation something that arises from the standard model, or what is it that leads them to conclude that they should've lost discernable amounts of energy?

ZorbaTehZ · 22-11-2011 8:17pm

roosh wrote: »

Rejection of FTL neurtino result

The rejection of the claim is based on the expectation that the neutrinos should have lost discernable amounts of energy, had they travelled faster than light. Just wondering, is this expectation something that arises from the standard model, or what is it that leads them to conclude that they should've lost discernable amounts of energy?

No, as far as I'm aware; for instance if you assume quantum mechanics and FTL propagation, then you get continuous emition of cerenkov radiationfor particles travelling FTL. But as far I know, Cohen & Glashow consider instead "forbidden processes" that can occur in FTL propagation, one of which causes a big energy loss. I don't know how (or if) these two gel together, since I don't know enough particle physics. Some blogs have been compiling lists of (otherwise obscure) papers of the last 20 years that have investigated the consequences of FTL propagation. But regarding the C&G paper, to quote Bell "it has a good pedigree" - the latter is a nobel laurate after all (if that counts for anything!).

krd · 23-11-2011 12:02am

roosh wrote: »

Rejection of FTL neurtino result

The rejection of the claim is based on the expectation that the neutrinos should have lost discernable amounts of energy, had they travelled faster than light. Just wondering, is this expectation something that arises from the standard model, or what is it that leads them to conclude that they should've lost discernable amounts of energy?

Is the implication of the neutrinos emitting Cerenkov radiation that the loss of energy would cause them to slow down?

If I've got this right - they haven't run a different experiment, they're just saying the neutrinos should have lost energy through Cernenkov radiation and throwing off electrons.

Curly Judge · 24-11-2011 10:16am

My reading of what they said is that if the neutrinos had not exhibited Chernenko radiation then they could not have been traveling FTL.
Have I got it wrong?

krd · 25-11-2011 7:28am

Curly Judge wrote: »

My reading of what they said is that if the neutrinos had not exhibited Chernenko radiation then they could not have been traveling FTL.
Have I got it wrong?

I know very little about this. Chernenko radiation is something that can be seen in nuclear reactors - I saw it in a documentary. In the documentary they said the blue light/glow in the reactors water was Chernenko radiation. I think given off by neutrons released in the reaction.

I would suppose, if the neutrinos are emitting Chernenko radiation, they have to be slowing down, or shrinking (do they shrink?). They can't be producing "free energy".

In the experiment, I don't think they were measuring the neutrinos emission of radiation, just their arrival times.

I think the other team are just saying, it's impossible because the Chernenko radiation would mean the neutrinos would have to lose energy, so they would have to slow down.

The whole thing could simply be they have a wrong bias set in their measuring equipment. They have to account for the time lag in the electronics of their measuring equipment - if they've over biased for the delay, they could easily get a FTL result.

FarmerGreen · 01-12-2011 3:18am

Light has a certain speed in a vacuum, in a denser medium like glass, much less, 0.7 say.
Its called the velocity factor.
Neutrinos dont interact with matter.
So, shooting a Neutrino beam through miles of rock (which it wont interact with) and expecting it to come out the other end as if it had travelled at the speed of light in this medium is, well, pushing it a bit.

Maybe I'm wrong.

krd · 01-12-2011 10:15am

FarmerGreen wrote: »

Light has a certain speed in a vacuum, in a denser medium like glass, much less, 0.7 say. Its called the velocity factor.

I was talking to someone a while back (a physicist), they told me light could be slowed to a stop, in super cooled crystals. Personally, I didn't study enough to get to the point of understanding why light slowed down in different mediums (or maybe I did but can't remember -there's a lot I can't remember)

Neutrinos dont interact with matter.

They have to interact with matter - otherwise, we'd have no way of telling they're there. The universe could be filled with particles that have no interaction with matter, and we'll never know they're there - because they will have no interactions with the observable universe.

So, shooting a Neutrino beam through miles of rock (which it wont interact with) and expecting it to come out the other end as if it had travelled at the speed of light in this medium is, well, pushing it a bit.

Maybe I'm wrong.

I'm assuming neutrinos can pass through miles of rock is because they're so small their probability of hitting anything is slim.........Which leaves me wondering who do they hit the detector? What is the detector?

I'm just assuming. I would like to know the answer to that one.

Podge_irl · 02-12-2011 7:50pm

krd wrote: »

They have to interact with matter - otherwise, we'd have no way of telling they're there. The universe could be filled with particles that have no interaction with matter, and we'll never know they're there - because they will have no interactions with the observable universe.

Which is essentially what dark matter is - only it interacts via the gravitational force but nothing else.

krd wrote: »

I'm assuming neutrinos can pass through miles of rock is because they're so small their probability of hitting anything is slim.........Which leaves me wondering who do they hit the detector? What is the detector?

I'm just assuming. I would like to know the answer to that one.

The detector only detects a minute fraction of the total number of neutrinos.

krd · 03-12-2011 12:05pm

Podge_irl wrote: »

Which is essentially what dark matter is - only it interacts via the gravitational force but nothing else.

A gravitational interaction would be an interaction with matter. If dark matter exists - if it was made up off darkions, it would just be recognised by their gravitational interaction. But that's a puzzle isn't it. Why don't they clump together and form darkstars and dark planets. Maybe because they don't exist. Or maybe they powerfully repel each other by some force that doesn't interact with anything in our world - and form gravity fogs. I don't know. It would explain why its' so hard to find even one darkion.

The detector only detects a minute fraction of the total number of neutrinos.

They're measuring pulses of neutrinos - they just need to see a fraction of the neutrinos within the pulses - and the shape of the recording will show, they're looking at the neutrinos from CERN - a neat square wave.

I'm not sure what detector they're using but I was looking at typical neutrino detectors on wikipedia. I would assume they're using a container with some liquid, surrounded by highly sensitive scintillation detectors (spark detectors - optical sensors). I would also assume they have sensors in there that can specifically pick up Cherenkov radiation.

My limited understanding, neutrinos will travel faster than the speed of light through the medium in their detector because of its' refractive index. So there should be Cherenkov radiation - which should be hard to miss. They should be able to see lovely pulses of it, that correspond with the pulses from CERN....It should be virtually impossible to miss (if it's there)

If they haven't seen the Cherenkov radiation, or haven't bothered looking for it. They may have been very sloppy.

Podge_irl · 04-12-2011 3:17am

Our inability to find a "darkion" (not a terminology I'm familiar with) is not even remotely unusual. We don't detect individual particles by their gravitational interaction as it's simply a far too weak effect.

Neutrinos will not travel through a medium FTL due to any refractive index.

krd · 04-12-2011 12:55pm

Podge_irl wrote: »

Our inability to find a "darkion" (not a terminology I'm familiar with) is not even remotely unusual. We don't detect individual particles by their gravitational interaction as it's simply a far too weak effect.

Dark matter is only seen in gravity calculations in astrophysics. Where the gravity exists in calculations based on observations, but the matter itself has not been observed.

Which is strange for many reasons - if there's so much of it, why can't we see any of it. If it's the same gravity as ordinary matter and there's so much of it - why aren't we seeing dark stars. Dark galaxies. If there's so much of it there why isn't that happening.

The individual particles may be too small to measure their gravitation interaction. But the astrophysics are measuring a huge gravitational interaction, for matter that can't be seen.

Neutrinos will not travel through a medium FTL due to any refractive index.

the refractive index n = speed of light in a vacuum / speed of light in medium.

n = c/Vp. It's the phase velocity in medium.

From the explanations I've seen of Cherenkov radiation, if a particle like a neutron, travels faster than the phase velocity of light in a medium, then it will cause Cherenkov radiation. Supposedly, something like the equivalent of a sonic boom from a jet travelling faster than the speed of sound.

himnextdoor · 02-01-2012 4:41pm

Perhaps it has something to do with the method through which neutrinos travel as opposed to how photons travel. Perhaps it is the case that a neutrino is an idealised photon and that the limit to the speed of light is just a little higher than we thought.

By way of an analogy, consider that space is a collection of points that exhibit a repulsive force such as to give rise to spontaneous expansion. Also, if we consider 'mass' as being bound energy and energy as being spacial vibrations, we can see that expansion is pervasive; space expands and so therefore mass and energy undergo expansion too and this maintains perspective i.e., each point of space can be considered a physical entity and over time, the volume of space increases as the density of repulsive points decreases.

Now take the case of an incandescant light-bulb; as electrons interact with the tungsten filament at a sub-atomic level, energy causes vibrations in the space local to the filament. In other words, the repulsive points that define space are swirled about; the normal expansion of space is interfered with and the paths of local points are altered. This in turn causes local space to interact with itself in a slightly different way and at low energy levels, the spacial-field just becomes slightly distorted.

However, as energy increases so too does the agitation of local space and at a high enough energy level, it is possible for 'points' of space to be pushed between other points so hard that an area of 'high pressure' is suddenly created and other local points 'feel' resistance and adjust their expansion path accordingly. But this high-energy point has a directional component and this means that the repulsive pressure is greater behind it than it is in front; space behind close the gap and the high energy point is forced through the next gap, then the next, in a kind of chain reaction that causes a wave to propogate and describes the photon.

Now, the photon does lose energy at a very small rate but this is almost exactly cancelled by the fact that as the points in space move apart, their repulsive force has less and less of an effect.

The thing is though, the space ahead of the photon is expanding and so a device that detects it is always moving away from the emitter in some respect; the 'real' distance between two points is always increasing and this increase is manifest as red-shift. Or to put it another way, from the perpective of a space point, light is constantly slowing down.

In this model though, there is a statistical probability for another consequence of spacial vibration. Instead of being pushed between points an excited space point might be made to collide with another point travelling the same direction. The chain reaction that followed would be like a Newton's cradle effect affecting space points directly. If the photon was light enough, it might actually be able to make used of the expansion energy itself such as to be unaffected by expansion at all.

A photon and a netrino set of from a point 'A' at the same time and are to be detected at some point, 'B' at some time later. Between points A and B there is a certain amount of space and therefore a certain number of space points which are constantly moving apart; that number can be 'P'. For the photon during flight, the number of space points passed each second will decrease; from its perspective, the volume of space is increasing. For a neutrino, however, the number of space points it passes remains constant since it experiences constant acceleration. The volume of space seems to remain constant fron its point of view. It seems likely that 'old' neutrinos could have accelerated to speeds far in excess of the speed of light over time. That's a mad notion isn't it?

Could it be that a photon travels 'through' space, between points, whereas neutrinos travel 'on' space, jumping from point to point and at each point picking up enough energy to counter expansion?

Perhaps a neutrino is simply a special case of photon; a photon that makes direct use of vacuum energy for a constant rate of acceleration.

I wonder, do neutrinos become red shifted over distance?

This could explain why neutrinos pass through matter too.

Morbert · 22-02-2012 9:59pm

Looks like it might have been a loose cable. Oops

darjeeling · 22-02-2012 11:10pm

Morbert wrote: »

Looks like it might have been a loose cable. Oops

Embarrassing, if that's the final conclusion. On the plus side, it won't be necessary to overturn all of physics.

Curly Judge · 23-02-2012 1:28am

Morbert wrote: »

Looks like it might have been a loose cable. Oops

Seifer · 23-02-2012 1:29am

Curly Judge wrote: »

http://news.sciencemag.org/scienceinsider/2012/02/breaking-news-error-undoes-faster.html

himnextdoor · 23-02-2012 3:33am

Seifer wrote: »

http://news.sciencemag.org/scienceinsider/2012/02/breaking-news-error-undoes-faster.html

It seems odd that no-one noticed that the data carried by the fibre optics was arriving later than expected; the neutrinos weren't arriving early, the light was arriving late!

A 60 nS delay equates to an extra 18 metres or so of extra distance travelled by light along the fibre-optic cable. What with GPS and relativity, shouldn't that anomaly have been spotted first?

Even horse-racing officials go to the trouble of analysing a 'photo-finish' before publishing results.

I think that this is very poor; how much research money needs to be spent on proving that Einstein knew what he was talking about?

Turtwig · 23-02-2012 10:35am

himnextdoor wrote: »

I think that this is very poor; how much research money needs to be spent on proving that Einstein knew what he was talking about?

As much as it takes to prove him wrong.

opinion guy · 23-02-2012 10:43am

himnextdoor wrote: »

It seems odd that no-one noticed that the data carried by the fibre optics was arriving laterearlier than expected; the neutrinos weren't arriving early, the light was arriving late!

A 60 nS delay earlyness equates to an extra 18 metres or so of extra distance travelled by light along the fibre-optic cable. What with GPS and relativity, shouldn't that anomaly have been spotted first?

Fixed that for you

Even horse-racing officials go to the trouble of analysing a 'photo-finish' before publishing results.

I think that this is very poor; how much research money needs to be spent on proving that Einstein knew what he was talking about?

Have you any idea how complicated this stuff is ? ALOT more complicated than your post which you managed to get back-assward

himnextdoor · 23-02-2012 12:15pm

opinion guy wrote: »

Fixed that for you

Have you any idea how complicated this stuff is ? ALOT morme complicated than your post which you managed to get back-assward

Hmm, a faulty connection made the signal arrive early?

Interesting.

opinion guy · 23-02-2012 1:08pm

himnextdoor wrote: »

Hmm, a faulty connection made the signal arrive early?

Interesting.

Read the link.

Edit: Reading it again it is ambiguous.

After tightening the connection and then measuring the time it takes data to travel the length of the fiber, researchers found that the data arrive 60 nanoseconds earlier than assumed. Since this time is subtracted from the overall time of flight, it appears to explain the early arrival of the neutrinos.

But in any case the most important point is:

New data, however, will be needed to confirm this hypothesis.

Nothing is proven nor disproven yet

himnextdoor · 24-02-2012 4:11am

opinion guy wrote: »

Read the link.

Edit: Reading it again it is ambiguous.

After tightening the connection and then measuring the time it takes data to travel the length of the fiber, researchers found that the data arrive 60 nanoseconds earlier than assumed. Since this time is subtracted from the overall time of flight, it appears to explain the early arrival of the neutrinos.

I'm confused; how was what I said 'ASSWAYS'? I think that your correction was 'ASSWAYS'! Are you saying that tightening the connection caused light to exceed the speed of light?

opinion guy wrote: »

But in any case the most important point is:

Nothing is proven nor disproven yet

That may be the case for you but I enthusiastically disagree.

opinion guy · 24-02-2012 1:03pm

himnextdoor wrote: »

I'm confused; how was what I said 'ASSWAYS'? I think that your correction was 'ASSWAYS'! Are you saying that tightening the connection caused light to exceed the speed of light?

No didn't say that. Clearly you have an issue with reading comprehension.

That may be the case for you but I enthusiastically disagree.

Its also the case for the scientists doing the experiements and the journalist reporting it - you know - like how I quoted. They need to do a new experiment and prove they were wrong.

shizz · 24-02-2012 2:49pm

I can't find where i read it but I presume someone here may have read it to, but I remember reading that they re did the experiment using atomic clocks instead and got the same result? How would this loose cable affect this?

Morbert · 24-02-2012 4:11pm

opinion guy wrote: »

No didn't say that. Clearly you have an issue with reading comprehension.

Its also the case for the scientists doing the experiements and the journalist reporting it - you know - like how I quoted. They need to do a new experiment and prove they were wrong.

In fairness, neither you nor the article explained it clearly.

himnextdoor, what happened was, due to the loose connection, there was a calibration issue with the clock. The receiver was overestimating the delay between detection and registration of the detection. This is not the delay between the emission and detection of the neutrino. Basically, if the neutrino is detected at time T, the computer will register the detection at T + delay, due to the delay in communitcation between the detector and the computer. Scientists subtract the delay time from the reading (I.e. They calculate T + delay - delay = T). When the connections were properly fastened, the delay turned out to be much smaller than they originally thought. Hence, beforehand they were calculating detection times that were too early.

krd · 24-02-2012 11:10pm

Morbert wrote: »

When the connections were properly fastened, the delay turned out to be much smaller than they originally thought. Hence, beforehand they were calculating detection times that were too early.

That sounds really iffy. You would expect that anyone with the kind of claim they had, would have spent weeks or even months stripping the equipment and retesting, to make absolutely sure there was no calibration issue.

A loose fibre cable doesn't sound right either - the difference in distance would be so small.

himnextdoor · 25-02-2012 1:55am

krd wrote: »

That sounds really iffy. You would expect that anyone with the kind of claim they had, would have spent weeks or even months stripping the equipment and retesting, to make absolutely sure there was no calibration issue.

A loose fibre cable doesn't sound right either - the difference in distance would be so small.

Yes. I'm having trouble with this too.

I think we are talking in terms of the problem being one of 'latency' that occurs between the input and output of a detecting device. It seems obvious that since detectors have to process their signal through various transducers, there will be a delay introduced by the detecting equipment itself and therefore any accurate calculation would have to take this delay into account.

It also seems reasonable that this would be achieved through the calibration process.

What doesn't make sense is that the initial calibration process (with the faulty connection) took the extra 60 nS delay into account; the initial value for the delay caused by the equipment and the loose connection was equated to 'extra distance in the path taken by light'. i.e., if the distance between two points is known then the 'shape' of a signal transmitted from point 'A' can be used to predict the shape of the signal arriving at a detector at point 'B'; the predicted signal at point 'B' can be compared to the output signal of the detector and the phase difference would correspond to the delay caused by the equipment. Every 60 nS of delay is eqivalent to the detecting equipment being 18 metres or so further away from the transmitter than it actually is.

So, they calibrated their equipment and carried out the experiment. And there was no suspicion of a faulty connection.

The clocks starts counting, a signal is transmitted from point 'A' and data starts flowing from point 'B'. Neutrinos are detected. The output signal of the detector is compared to the signal that would be expected if the neutrinos were travelling at light-speed in which case there would be no phase difference. Any detected phase difference would correspond to the speed of neutrinos when compared to the speed of light.

But the experiment reported that neutinos were travelling faster than light which means that the loose connection was actually tight when the experiment was conducted. In order for the data to show a 60 nS phase shift between photons and neutrinos, the fault cannot have been present during the experiment. If it was present, then the data would have shown no phase-shift (dealt with in calibration) and the experiment would have concluded that neutrinos do not travel faster than light.

How did they determine that a connection that was tight during the experiment was loose in the calibration process before it?

It sounds sloppy at best but then I would still like to know the mechanism by which a loose connection can introduce precisely 60 nS of delay into a system. Even assuming that the connections were electrical in nature rather than fibre-optic and taking into account the fact that changes in 'capacitance' and 'inductance' can cause a small delay through poor connection, 60 nS sounds a lot.

And as I have already said, from a fibre-optics viewpoint, 60 nS equates to an extra 18 metres or so distance travelled by light. Or an 18 metre GPS error. Or 'x' number of clock-ticks that weren't counted.

I think that the loose connection theory is more about saving face that it is about anything else and that it was something else that went wrong, something that would undermine credibility perhaps.

It's disappointing; I had rather hoped that the difference in the speeds of neutrinos and photons would be directly related to the rate of expansion of the Universe.

Morbert · 26-02-2012 5:24pm

himnextdoor wrote: »

Yes. I'm having trouble with this too.

I think we are talking in terms of the problem being one of 'latency' that occurs between the input and output of a detecting device. It seems obvious that since detectors have to process their signal through various transducers, there will be a delay introduced by the detecting equipment itself and therefore any accurate calculation would have to take this delay into account.

It also seems reasonable that this would be achieved through the calibration process.

What doesn't make sense is that the initial calibration process (with the faulty connection) took the extra 60 nS delay into account; the initial value for the delay caused by the equipment and the loose connection was equated to 'extra distance in the path taken by light'. i.e., if the distance between two points is known then the 'shape' of a signal transmitted from point 'A' can be used to predict the shape of the signal arriving at a detector at point 'B'; the predicted signal at point 'B' can be compared to the output signal of the detector and the phase difference would correspond to the delay caused by the equipment. Every 60 nS of delay is eqivalent to the detecting equipment being 18 metres or so further away from the transmitter than it actually is.

So, they calibrated their equipment and carried out the experiment. And there was no suspicion of a faulty connection.

The clocks starts counting, a signal is transmitted from point 'A' and data starts flowing from point 'B'. Neutrinos are detected. The output signal of the detector is compared to the signal that would be expected if the neutrinos were travelling at light-speed in which case there would be no phase difference. Any detected phase difference would correspond to the speed of neutrinos when compared to the speed of light.

But the experiment reported that neutinos were travelling faster than light which means that the loose connection was actually tight when the experiment was conducted. In order for the data to show a 60 nS phase shift between photons and neutrinos, the fault cannot have been present during the experiment. If it was present, then the data would have shown no phase-shift (dealt with in calibration) and the experiment would have concluded that neutrinos do not travel faster than light.

How did they determine that a connection that was tight during the experiment was loose in the calibration process before it?

It sounds sloppy at best but then I would still like to know the mechanism by which a loose connection can introduce precisely 60 nS of delay into a system. Even assuming that the connections were electrical in nature rather than fibre-optic and taking into account the fact that changes in 'capacitance' and 'inductance' can cause a small delay through poor connection, 60 nS sounds a lot.

And as I have already said, from a fibre-optics viewpoint, 60 nS equates to an extra 18 metres or so distance travelled by light. Or an 18 metre GPS error. Or 'x' number of clock-ticks that weren't counted.

I think that the loose connection theory is more about saving face that it is about anything else and that it was something else that went wrong, something that would undermine credibility perhaps.

It's disappointing; I had rather hoped that the difference in the speeds of neutrinos and photons would be directly related to the rate of expansion of the Universe.

I have found a more thorough article. Apparently it is not the connection between the detector and the computer, but rather the GPS antenna and the computer.

http://www.bbc.co.uk/news/science-environment-17139635

This sounds entirely plausible.

krd · 26-02-2012 6:15pm

Morbert wrote: »

I have found a more thorough article. Apparently it is not the connection between the detector and the computer, but rather the GPS antenna and the computer.

http://www.bbc.co.uk/news/science-environment-17139635

This sounds entirely plausible.

I don't know. They're still claiming it was a lose fibre cable. I've worked with those cables, and probably the same kind of hardware their using for the computer. Usually, a loose cable wouldn't make a difference, unless it was nearly hanging out of its slot. If you're having a problem with the cable, you'll see intermittent drops in the signal. I don't see where you would get a latency.

Accurately figuring out the latencies in the electronics might be more difficult. If they were wrong in calculating or measuring the latencies within their equipment, it would explain where they went wrong.

Morbert · 26-02-2012 7:02pm

krd wrote: »

I don't know. They're still claiming it was a lose fibre cable. I've worked with those cables, and probably the same kind of hardware their using for the computer. Usually, a loose cable wouldn't make a difference, unless it was nearly hanging out of its slot. If you're having a problem with the cable, you'll see intermittent drops in the signal. I don't see where you would get a latency.

Accurately figuring out the latencies in the electronics might be more difficult. If they were wrong in calculating or measuring the latencies within their equipment, it would explain where they went wrong.

A variation of 60 billionths of a second wouldn't make a difference in a lot of situations. But when you are dealing with resolutions on their level, it makes all the difference in the world.

krd · 26-02-2012 7:26pm

Morbert wrote: »

A variation of 60 billionths of a second wouldn't make a difference in a lot of situations. But when you are dealing with resolutions on their level, it makes all the difference in the world.

I know. But a loose fibre optic cable, at most the distance is in the range of a millimetre. 60ns, gives an error of about 18 metres.

You'd definitely see latencies of 60ns, and much more, in the electronics.

Morbert · 26-02-2012 8:35pm

krd wrote: »

I know. But a loose fibre optic cable, at most the distance is in the range of a millimetre. 60ns, gives an error of about 18 metres.

You'd definitely see latencies of 60ns, and much more, in the electronics.

http://arxiv.org/pdf/1109.4897v2

The timing apparatus schematics are figures 3 and 6. Latency is not just due to wire distance, which is why the apparatus had to go through intensive calibrations in the beginning. They certainly would not have been able to predict the latency to within 60ns by considering wire distance.

The collaboration are going to be running the experiment again, the next time the beam is available, with the fixed connection (and a few fixes of other possible sources of error) which will definitively determine whether or not the problem was in the apparatus.

Scartbeg · 26-02-2012 9:12pm

FWIW a delay of 60ns would correspond to approx 12m travel in an optic fibre which will have a refractive index of approx 1.5

More likely a bad connection would result in multiple reflections between the optical surfaces concerned which would cause multiple or mis-shapen pulses to be received

himnextdoor · 27-02-2012 6:30am

Scartbeg wrote: »

FWIW a delay of 60ns would correspond to approx 12m travel in an optic fibre which will have a refractive index of approx 1.5

More likely a bad connection would result in multiple reflections between the optical surfaces concerned which would cause multiple or mis-shapen pulses to be received

Which would fail to match the 'comparative data' and would as a result raise a red flag on the experiment.

The data (in the form of neutrino bursts) was 'pulsed', was it not, which means there was a 'reference' to which the output data could be compared.

In any event, I fail to see how a loose connection, especially a fibre-optic connection, could introduce precicely 60 nS of delay for the entire duration of the experiment without raising a few eye-brows...

... especially when you consider that they discovered that the problem was due to a loose connection that was actually tight when the experiment was performed...

Chuck Stone · 27-02-2012 6:51am

I was pretty sure it was going to be something simple like that.

No actually - I haven't a clue tbh.

himnextdoor · 27-02-2012 7:21am

krd wrote: »

I know. But a loose fibre optic cable, at most the distance is in the range of a millimetre. 60ns, gives an error of about 18 metres.

You'd definitely see latencies of 60ns, and much more, in the electronics.

Yes. And this could easily dealt with by comparing the phase-shift between output and a mathematically calculated 'expected' input to the detector; this kind of latency is easily calculated.

I use music recording software and MIDI equipment and am constantly dealing with latency issues effectively and I don't require billions of dollars worth of funding to achieve this; why do CERN, etc.?

And how does one explain the intermittent nature of a loose connection when the connection was actually sound for the duration of the experiment? It would have to be in order for the experiment to produce the data that showed that neutrinos travel faster than light... or through another dimension... or whatever...

The error must have occurred during calibration. Whether that be with the clocks, the GPS or whatever else is involved, somebody cocked something up.

I mean, how could they determine that a connection that is tight was loose?

Or else the physics is wrong; what if that is what they have dicovered? How would we know?

himnextdoor · 27-02-2012 8:04am

Morbert wrote: »

I have found a more thorough article. Apparently it is not the connection between the detector and the computer, but rather the GPS antenna and the computer.

http://www.bbc.co.uk/news/science-environment-17139635

This sounds entirely plausible.

To be honest, this article rather makes my point, I think; consider:

Under the heading of 'Faulty Connection?' the article explains that:

"The two problems the team has identified would have opposing effects on the apparent speed.

On the one hand, the team said there is a problem in the "oscillator" that provides a ticking clock to the experiment in the intervals between the synchronisations of GPS equipment.

This is used to provide start and stop times for the measurement as well as precise distance information.

That problem would increase the measured time of the neutrinos' flight, in turn reducing the surprising faster-than-light effect"

So, is the oscillator running too quickly or too slowly? What is so hard about that? I mean, what does '4 GHz' actually mean in the real world?

Did they think the clock was ticking faster than it actually was?

It can't have been that, can it? Do you see what I mean though?

They seem to be saying that 'there may be a problem with the clock' and that this 'fault' would cause the clock to count more quickly in order to indicate sub-ligh-speed travel by neutrinos, should such a fault exist; how do they know it wasn't counting too slowly? How can that happen at CERN?

Or it might have been a loose connection [EDIT which would indicate FTL travel by neutrinos.EDIT] Give us a break. Are they for real?

I might be considered a cynic but I think that someone is looking for more funding; someone who likes to play with really big toys.

krd · 27-02-2012 10:18am

himnextdoor wrote: »

Yes. And this could easily dealt with by comparing the phase-shift between output and a mathematically calculated 'expected' input to the detector; this kind of latency is easily calculated.

Yeah..... but unless they know latency is static, they may need to recalibrate it continuously.

I use music recording software and MIDI equipment and am constantly dealing with latency issues effectively and I don't require billions of dollars worth of funding to achieve this; why do CERN, etc.?

I would say, the latency of your music software and MIDI fluctuates.

And how does one explain the intermittent nature of a loose connection when the connection was actually sound for the duration of the experiment? It would have to be in order for the experiment to produce the data that showed that neutrinos travel faster than light... or through another dimension... or whatever...

I used to test Telecoms equipment. Fibre could be a pain in the ass for a few reasons. The switching is in nano seconds - but if the cable was "loose", and there was an intermittent problem, you'd lose part of the signal - if it was completely off, you'd know all about it - as you wouldn't get any signal.

The error must have occurred during calibration. Whether that be with the clocks, the GPS or whatever else is involved, somebody cocked something up.

It could be that they don't want to admit to sloppy calibration. And there could be politics involved - and finger pointing. And whoever was in charge of making sure the cable was in "tight" is the least politically powerful.

I mean, how could they determine that a connection that is tight was loose?

You just un-seat the cable and reseat it. And the little light on those cards that's normally useless - if there's a signal coming from the other end, will flash to let you know it's in properly. And there are a couple of boo boos I can think of. If you calibrated while the computer was cool, and then you let if get very warm, your calibration could be very far off. The cards can vary too - sometimes manufacturers are sloppy, and there are problems with the cards.

There would also be a margin of error as regards the refractive index of the cable.

Or else the physics is wrong; what if that is what they have dicovered? How would we know?

If someone can repeat the experiment and get similar results, then there could be new physics.. But that's probably not going to happen.

Morbert · 27-02-2012 12:59pm

Guys, conspiracy theories don't help anyone. People were rushing to get their names on the paper, and a bad connection is possibly one of the most embarrassing, least interesting issues. It is not something they would fabricate.

himnextdoor, as you can see from the paper, which I urge you to read, it is not simply a case of running a wire across a room. There are multiple sources of delays, and spurious receiver data is not something that calibration would have easily picked up. We are talking about nanosecond synchronisation. You also seemed surprised that the delay is 60 ns. If this really was the source of the delay, it makes perfect sense, as that was how early the neutrinos are arriving.

Either way, as I said before, they certainly haven't washed their hands of the whole issue. It will be interesting to see what the new results will be.

himnextdoor · 01-03-2012 3:04am

Morbert wrote: »

Guys, conspiracy theories don't help anyone. People were rushing to get their names on the paper, and a bad connection is possibly one of the most embarrassing, least interesting issues. It is not something they would fabricate.

himnextdoor, as you can see from the paper, which I urge you to read, it is not simply a case of running a wire across a room. There are multiple sources of delays, and spurious receiver data is not something that calibration would have easily picked up. We are talking about nanosecond synchronisation. You also seemed surprised that the delay is 60 ns. If this really was the source of the delay, it makes perfect sense, as that was how early the neutrinos are arriving.

Either way, as I said before, they certainly haven't washed their hands of the whole issue. It will be interesting to see what the new results will be.

I did read that paper but it still seems to me that CERN are saying that on the one hand there may be a fault that makes neutrinos appear to travel faster than light but on the other hand there may be a fault that makes neutrinos travel at sub-luminal speed but on another hand (how many hands are there?) there may not be a fault at all.

i.e., the results may be correct or they could be incorrect in one of at least two ways.

It doesn't inspire confidence does it?

And I would love to know how a fibre-optic's connection can eliminate a 60 nS delay and also, how do they know that the clock would count more slowly in the event of a fault; how can they discount the possibility that it counted too quickly?

They seem to know too much without actually being able to know anything and that is not very scientific in my view and consequently denegrades the work done at CERN.

And don't forget that if it was a loose connection that caused the fault, then it wasn't loose during the performance of the experiment. If it was, then the experiment would have found that neutrinos do not travel at super-luminal speed. If the connection was 'tight' in calibration and 'loose' during the experiment then neutrinos would have been judged to have travelled even more slowly.

How and why would they even suspect that there could be a problem with a loose connection that was obviously tight while the data was being gathered?

It reminds me of a plumber who is trying to screw extra money out of a doddery old woman...

Do you remember the 'millenium-bug' fiasco that caused great consternation and a great deal of cost to the 'educated public'? And do you remember the news reports from about thirty-years ago that a 7400 series TTL logic chip was responsible for almost causing World War 3?

People will buy anything from guys in white coats.

Morbert · 01-03-2012 2:51pm

"People will buy anything from guys in white coats." said himnextdoor, using CERN's hypertext transfer protocol, on a personal computer, or smartphone.

You're building conclusions from only half the data.

EDIT: Also, the millennium bug was indeed a problem. A problem that companies successfully took action against and solved.

himnextdoor · 01-03-2012 7:31pm

When we stop questioning the agendas of those in authority, we submit completely to their will.

When they say 'jump', most say 'how high?'
When they say 'jump', I ask them 'why?'

All I am saying is that it is perfectly reasonable to speculate about what might have gone wrong. Especially if you take into account that it was okay speculate when we thought neutrinos travelled at super-luminal speed. (How much data, as a fraction of the available data, was considered in coming to that conclusion?)

Morbert wrote: »

"People will buy anything from guys in white coats." said himnextdoor, using CERN's hypertext transfer protocol, on a personal computer, or smartphone.

Meaning what? Are you suggesting that only people that have nothing to do with new technology may criticise or comment about it?

Morbert wrote: »

You're building conclusions from only half the data.

And CERN based their conclusions on more than half the data?

In any case, I believe that I am taking into account all of the data available to me.

Morbert wrote: »

EDIT: Also, the millennium bug was indeed a problem. A problem that companies successfully took action against and solved.

As I said, people will buy anything from guys in white coats.

The millenium-bug fiasco was nothing more that a scam to take advantage of ignorance. It was fifty quid to get your computer checked out and washing machines, toasters and irons were at risk too... give me a break.

Morbert · 01-03-2012 8:00pm

himnextdoor wrote: »

When we stop questioning the agendas of those in authority, we submit completely to their will.

When they say 'jump', most say 'how high?'
When they say 'jump', I ask them 'why?'

All I am saying is that it is perfectly reasonable to speculate about what might have gone wrong. Especially if you take into account that it was okay speculate when we thought neutrinos travelled at super-luminal speed. (How much data, as a fraction of the available data, was considered in coming to that conclusion?)

But your speculation regarding a conspiracy theory is entirely unreasonable.

Meaning what? Are you suggesting that only people that have nothing to do with new technology may criticise or comment about it?

Meaning you are completely misinformed about the "guys in white coats", as evidenced by all their technology you are using. You are accusing an institution who revolutionised global networks of not understanding cables.

And CERN based their conclusions on more than half the data?

In any case, I believe that I am taking into account all of the data available to me.

No you are not. You are projecting your own charicature of the data.

As I said, people will buy anything from guys in white coats.

The millenium-bug fiasco was nothing more that a scam to take advantage of ignorance. It was fifty quid to get your computer checked out and washing machines, toasters and irons were at risk too... give me a break.

That was not the millenium-bug fiasco. This was

http://en.wikipedia.org/wiki/Year_2000_problem

krd · 01-03-2012 8:09pm

himnextdoor wrote: »

The millenium-bug fiasco was nothing more that a scam to take advantage of ignorance. It was fifty quid to get your computer checked out and washing machines, toasters and irons were at risk too... give me a break.

No, the millenium bug was not a scam. I worked for a company whose entire accounts system had to be junked because of the bug.

Now, anyone charging 50 quid to check your computer for the bug was taking the piss. But it was widespread in some systems where they'd widely used the short year - or used the date time and year in a way that would cause the logic of their software to go haywire.

opinion guy · 01-03-2012 9:08pm

You know - the thread title is simply misleading. Are we really expected that the CERN people accelerated a whole scientist(s) to faster than the speed of light ?

himnextdoor · 02-03-2012 6:48am

Morbert wrote: »

But your speculation regarding a conspiracy theory is entirely unreasonable.

Meaning you are completely misinformed about the "guys in white coats", as evidenced by all their technology you are using. You are accusing an institution who revolutionised global networks of not understanding cables.

No you are not. You are projecting your own charicature of the data.

That was not the millenium-bug fiasco. This was

http://en.wikipedia.org/wiki/Year_2000_problem

Dude, your credibility just went BANG!!!

Won't you question Wikipedia? Of course you won't question CERN..

himnextdoor · 02-03-2012 6:57am

krd wrote: »

No, the millenium bug was not a scam. I worked for a company whose entire accounts system had to be junked because of the bug.

Now, anyone charging 50 quid to check your computer for the bug was taking the piss. But it was widespread in some systems where they'd widely used the short year - or used the date time and year in a way that would cause the logic of their software to go haywire.

Then either you don't understand logic or you don't understand haywire,

What, in your opinion, is the worst thing that could have happened due to the 'milenium-bug'?

What? Someone might have received documentation that was dated one-hundred years too early?

WORLD-STOPPING.

You were, and obviously still are, a trainee.

Big story ....CERN scientists break the speed of light

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