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CERN clocks faster-than-light neutrinos

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T

ThoseDeafMutes

Member
KHarvey16 said:
The explanation needs clarification. It seems to say it was loose and when they tightened it the signal arrived 60 nanoseconds quicker than they assumed. This doesn't really make much sense since the neutrinos were 60 nanoseconds early with what was presumably a loose connection. Unless the tightness of the connection was irrelevant to the result, in which case it's odd they mention it.
Click to expand...


Most likely an error in the reporting.
 
M

marrec

Banned
astroturfing said:
i think also Michio Kaku predicted this (in some youtube vid), that it would be some error that has to do with the GPS...

oh well. maybe the Higgs is itself massless and travels faster than light? lol.
Click to expand...

Everyone predicted this.

Also, this is still just a rumor and not officially confirmed by CERN.
 
O

orientalNoodle

Banned
astroturfing said:
yeah i was just joking. i understand the Higgs is expected to be found somewhere around the 115-125GeV range? i don't quite know how that compares to other particles though. much more massive than an electron or photon at least..?
Click to expand...

I just check Wiki and an electron is like 0.51MeV and the Higgs at low end range is 115GeV.
So the Higgs is like 225490196 times more massive.
 
C

Conciliator

Banned
Too bad if true! Cause, you know, upending current scientific theory would be cool I guess. But, science is science because it knows when to accept the boring truths(and also is able to accept making mistakes).
 
S

Stinkles

Clothed, sober, cooperative
Timedog said:
I just meant that the speed of light always just seemed like an arbitrary stopping point for reality. What if there's tons of "stuff" zipping around at speeds faster than the speed of light? What if dark energy/matter is "stuff" that is in a state that is seemingly unmeasurable or extremely hard to measure on a per "particle" or "unit" basis (like perhaps "things" that are FTL), but we can see them in aggregate over huge cosmic distances. Who knows? I just don't know why anyone would make the assumption that existence stops at FTL when we obviously don't know a whole lot about our universe.

It would be interesting if we actually somehow measured something that was faster than the speed of light though.
Click to expand...

Well this is a property of the visible dimensions of spacetime. And it's not a constant. That speed changed and settled immediately "after" the big bang. So in different universes, it could be a wildly different upper limit. Of course there's nothing preventing a force or particle from warping spacetime to get around the practical limitations of the speed limit (without breaking it). Well, I mean, a lot of things prevent that, but not special relativity. Of course, then you have the question of causality. For some reason, in my head, causality seems literally unbreakable and that "feels" right, whereas the speed of light "feels" wrong as an absolute barrier.

Feelings.
 
T

The Technomancer

card-carrying scientician
OuterWorldVoice said:
Well this is a property of the visible dimensions of spacetime. And it's not a constant. That speed changed and settled immediately "after" the big bang. So in different universes, it could be a wildly different upper limit. Of course there's nothing preventing a force or particle from warping spacetime to get around the practical limitations of the speed limit (without breaking it). Well, I mean, a lot of things prevent that, but not special relativity. Of course, then you have the question of causality. For some reason, in my head, causality seems literally unbreakable and that "feels" right, whereas the speed of light "feels" wrong as an absolute barrier.

Feelings.
Click to expand...

Nothiiing more then feeeeeeelings!
 
A

astroturfing

Member
orientalNoodle said:
I just check Wiki and an electron is like 0.51MeV and the Higgs at low end range is 115GeV.
So the Higgs is like 225490196 times more massive.
Click to expand...

hah, crazy. had no idea :O

so it's much more massive than many other known particles... is it then harder to find because it's so short-lived and decays into other stuff so fast? and in the results there's so much noise that it's like finding a needle in a haystack (obvious understatement)...? just wondering if i got this right.
 
C

Conciliator

Banned
Any particularly learned and articulate person want to explain the connection between the speed of light and causality? I've never been quite able to comprehend that.
 
T

ThoseDeafMutes

Member
Conciliator said:
Any particularly learned and articulate person want to explain the connection between the speed of light and causality? I've never been quite able to comprehend that.
Click to expand...

I don't think we have any of those around here. The root cause of the issue is the relativity of simultaneity - the idea that two events cannot said to have occurred simultaneously if they are separated by distance. There is a thought experiment known as the Tachyon Pistol Duel. It is as follows:

There are two men who meet at a point in space. They agree to take their spaceships, fly away from each other at 0.866 times the speed of light, count down 8 seconds, then turn and fire their tachyon cannons at each other. These weapons fire in a path at infinite speed, and stop when they strike their target. Since there are particles littered through space, every now and again one of the tachyons in the beam it fires will hit them and release detectable radiation. There is a time dilation factor of 2 between man A and man B once they are going at 0.866 away from each other - this means that according to each man, the other is going at half speed.

Man A counts down to 0 seconds, turns and fires at man B. According to man A, man B is at half speed, so he has only counted down to 4 seconds by this stage. The beam being instant, breezes past B, missing by a hair's length. Man B's ship detects the tachyon beam that flew past, and is enraged that man A fired before the time was up! According to his clock, man A should only have counted down to 6 by now. He retaliates, and destroys man A's instantly. Man A is now dead, a full 6 seconds before he fired his shit.

This is already a time paradox, but it gets worse. This event sequence only occurred because we followed man A's perspective from the start. If you follow man B's instead, the exact opposite should have occurred. So you have two mutually contradictory sequences of events, both of which ought to have happened, both of which result in a time paradox.

Although Einstein's equations describe why simple velocity addition cannot ever lead an object to attain superluminal velocities, the two postulates of Special Relativity are, alone, far more damning. Time dilation is something that has been experimentally verified, both gravitational (via GPS synchronization) and relativistic (via particle accelerators measuring radio-isotope decay). The above thought experiment is extremely idealized - FTL being "instantaneous", but paradoxes arise with non-infinite velocities as well. If you go Warp 7 to Alpha Centauri and back again, you will arrive before you left. The speed at which objects can go while NEVER causing a paradox from ANY reference frame is... the speed of light.
 
A

AAequal

Banned
Opera Result Affected By Instrumental Error !
This just in: the controversial Opera result on superluminal neutrinos is affected by a previously unaccounted for experimental error, which completely overturns the conclusions.

This is explained in detail here. Note that the source is James Gillies, head of Communications at CERN, and thus hardly a "unofficial leak". In fact, tomorrow there will be a CERN press release on the matter.

The relevant quote is the following: 

"earlier this month scientists found a problem in the GPS system used to time the arrival of neutrino particles at an underground lab in Italy.
Gillies says only further measurements planned for later this year will confirm whether the problem introduced an error that made the neutrinos appear to move faster than light."

It appears that the source of the problem is a connection of a fiber optic cable to a hardware board, which introduces a time delay which gets subtracted in the neutrino timing measurement. 
So, no new physics from Opera neutrinos after all. Einstein may rest in peace, Relativity holds, and new physics model builders can have a good night of sleep tonight.

An additional link is here. From it you get to know (but I am not sure one should trust this information literally) that the time delay, after fixing the connection, equals 60 nanoseconds - exactly the discrepancy with the expected timing of neutrinos.

It remains to wait for the press conference. I must say I am relieved -I was never a big fan of the Opera finding. If new physics needs  to emerge somehow from the present generation of particle physics experiments, I have all reasons to believe it will do so at the LHC. And still, I believe it won't... But that is another story.
Click to expand...
Source: science20
You can probably check the press live from CERN's official site. While we have to wait for the test later this year it does seem like neutrinos don't move faster then light.
 
A

AAequal

Banned
From CERN
UPDATE 23 February 2012

The OPERA collaboration has informed its funding agencies and host laboratories that it has identified two possible effects that could have an influence on its neutrino timing measurement. These both require further tests with a short pulsed beam. If confirmed, one would increase the size of the measured effect, the other would diminish it. The first possible effect concerns an oscillator used to provide the time stamps for GPS synchronizations. It could have led to an overestimate of the neutrino's time of flight. The second concerns the optical fibre connector that brings the external GPS signal to the OPERA master clock, which may not have been functioning correctly when the measurements were taken. If this is the case, it could have led to an underestimate of the time of flight of the neutrinos. The potential extent of these two effects is being studied by the OPERA collaboration. New measurements with short pulsed beams are scheduled for May.
Click to expand...
 
T

twobear

sputum-flecked apoplexy
ThoseDeafMutes said:
I don't think we have any of those around here. The root cause of the issue is the relativity of simultaneity - the idea that two events cannot said to have occurred simultaneously if they are separated by distance. There is a thought experiment known as the Tachyon Pistol Duel. It is as follows:

There are two men who meet at a point in space. They agree to take their spaceships, fly away from each other at 0.866 times the speed of light, count down 8 seconds, then turn and fire their tachyon cannons at each other. These weapons fire in a path at infinite speed, and stop when they strike their target. Since there are particles littered through space, every now and again one of the tachyons in the beam it fires will hit them and release detectable radiation. There is a time dilation factor of 2 between man A and man B once they are going at 0.866 away from each other - this means that according to each man, the other is going at half speed.

Man A counts down to 0 seconds, turns and fires at man B. According to man A, man B is at half speed, so he has only counted down to 4 seconds by this stage. The beam being instant, breezes past B, missing by a hair's length. Man B's ship detects the tachyon beam that flew past, and is enraged that man A fired before the time was up! According to his clock, man A should only have counted down to 6 by now. He retaliates, and destroys man A's instantly. Man A is now dead, a full 6 seconds before he fired his shit.

This is already a time paradox, but it gets worse. This event sequence only occurred because we followed man A's perspective from the start. If you follow man B's instead, the exact opposite should have occurred. So you have two mutually contradictory sequences of events, both of which ought to have happened, both of which result in a time paradox.

Although Einstein's equations describe why simple velocity addition cannot ever lead an object to attain superluminal velocities, the two postulates of Special Relativity are, alone, far more damning. Time dilation is something that has been experimentally verified, both gravitational (via GPS synchronization) and relativistic (via particle accelerators measuring radio-isotope decay). The above thought experiment is extremely idealized - FTL being "instantaneous", but paradoxes arise with non-infinite velocities as well. If you go Warp 7 to Alpha Centauri and back again, you will arrive before you left. The speed at which objects can go while NEVER causing a paradox from ANY reference frame is... the speed of light.
Click to expand...

hah, very cute. i'm stealing this.
 
M

Mudkips

Banned
ThoseDeafMutes said:
Man A counts down to 0 seconds, turns and fires at man B. According to man A, man B is at half speed, so he has only counted down to 4 seconds by this stage. The beam being instant, breezes past B, missing by a hair's length. Man B's ship detects the tachyon beam that flew past, and is enraged that man A fired before the time was up! According to his clock, man A should only have counted down to 6 by now. He retaliates, and destroys man A's instantly. Man A is now dead, a full 6 seconds before he fired his shit.
Click to expand...

Not really.
In Man A's frame of reference, Man B is at 4 on the countdown when Man A fires.
In Man B's frame of reference, Man B does NOT see Man A's shot when Man B is at 4 on the countdown. In Man B's frame of reference, Man B sees Man A's shot when Man B is at 0.

Man A shoots when he sees Man B at 4 on the countdown.
Man B shoots when he sees Man A at 4 on the countdown.
Man A and Man B are actually both at 0 on the countdown, from their respective perspectives, when they fire. When a bullet hits them or something near them, they know that the other fired when they saw him at 4 on the countdown, not when the other was at 4 on the countdown.
 
J

Jackpot

Banned
Mudkips said:
Not really.
In Man A's frame of reference, Man B is at 4 on the countdown when Man A fires.
In Man B's frame of reference, Man B does NOT see Man A's shot when Man B is at 4 on the countdown. In Man B's frame of reference, Man B sees Man A's shot when Man B is at 0.

Man A shoots when he sees Man B at 4 on the countdown.
Man B shoots when he sees Man A at 4 on the countdown.
Man A and Man B are actually both at 0 on the countdown, from their respective perspectives, when they fire. When a bullet hits them or something near them, they know that the other fired when they saw him at 4 on the countdown, not when the other was at 4 on the countdown.
Click to expand...

Maybe he explained it wrong but the Jouster's Paradox is a well-documented thought experiment (Two knights charge each other at close to light speed. Due to relative mass each knight's lance gets shorter from the opposite's perspective).

If you were able to exceed the speed of light a knight could be stabbed with a lance and be able to stop it from happening due to the order of events from his perspective, one of the reasons light speed is as fast as it is possible to go in this universe.
 
O

okdakor

Member
AAequal said:
ICARUS Refutes OPERA's Superluminal Neutrinos - AGAIN!
Click to expand...

En1VQ.jpg
 
M

Mudkips

Banned
Jackpot said:
Maybe he explained it wrong but the Jouster's Paradox is a well-documented thought experiment (Two knights charge each other at close to light speed. Due to relative mass each knight's lance gets shorter from the opposite's perspective).

If you were able to exceed the speed of light a knight could be stabbed with a lance and be able to stop it from happening due to the order of events from his perspective, one of the reasons light speed is as fast as it is possible to go in this universe.
Click to expand...

That's a different scenario. What he posted refers to subluminal travelers and simultaneous superluminal shot after travel. An external reference frame shows that nothing fancy (beyond the tachyon bullet) happens.
 
L

LCfiner

Member
CERN confirms its mistake, neutrinos obey the speed limit of light after all


http://www.theverge.com/2012/6/8/3072393/speed-of-light-neutrino-mistake-cern

CERN has confirmed that the anomalous results which indicated that neutrinos traveled faster than the speed of light were caused by faulty machinery. The findings were reported on heavily last September, and since then scientists the world over have been trying to explain how the neutrinos broke one of the fundamental laws of physics. Earlier this year, there was word that the team behind the results had found possible faults in its test equipment, and the error has now been confirmed.

While it may seem like a huge blow to the team, CERN Research Director Sergio Bertolucci was pragmatic in his summary of the events. He thanked the scientific community for its collaboration on finding the error, and explained why mishaps like this show the strength of science:
Click to expand...

so that's that, mattress man
 
E

ElectricBlue187

Member
I remember from the very beginning the dudes at CERN were like "this is probably just an error somewhere we can't find....but...." It's cool to see science at work.
 
L

LCfiner

Member
BruiserBear said:
I'm glad to hear this. For some reason it kind of freaked me out to think Einstein could have been wrong. :p
Click to expand...

I was excited to think that it could be real but it's a relief to know it was an error.

there are enough mysteries of the universe without having to add a major one like this :)
 
A

Asbel

Member
This is how people improve.

Carl Sagan said:
In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion.

1987 CSICOP Keynote Address
Click to expand...
 
B

BruiserBear

Banned
LCfiner said:
I was excited to think that it could be real but it's a relief to know it was an error.

there are enough mysteries of the universe without having to add a major one like this :)
Click to expand...

My thoughts exactly. If we're wrong about the speed limit of the universe, what the hell else are we wrong about?
 
M

Man

Member
CERN Research Director Sergio Bertolucci was pragmatic in his summary of the events. He thanked the scientific community for its collaboration on finding the error, and explained why mishaps like this show the strength of science
Click to expand...
Excellent.
 
M

methane47

Member
"CERN Research Director Sergio Bertolucci was pragmatic in his summary of the events. He thanked the scientific community for its collaboration on finding the error, and explained why mishaps like this show the strength of science"

---"Ooopss scratch that, I was wrong....... SCIENCE!!!"
 
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