lhc neutrino faster than the speed of light

[moti barski]

heard in the news that the Large Hadron Collider ( LHC ) research announced that the
neutrino moves faster than the speed of light, and I would like to read what you heard about this.

also, was it proved, and do you think the neutrino actually teleported.

[BlindSniper]

This is a quite interesting subject for me. And to be honest I'm not sure if it teleported or went faster than the speed of light.Teleportation seems unlikely because when did the particle know when to re appear.

From a quick calculation it seems that they move about 15376.35517082 m/s faster than light, which is not much faster than the speed of light. I think these results might be a little out, but if it was proven then this news is very exciting.

[BlindSniper]

Sorry Double post.

[NickThissen]

You need to be a bit more subtle in your wording. First of all I don't think this has much to do with the LHC research at all. The neutrino's used might be generated (in part) with help of the LHC (I don't know) but beside that it's got nothing to do with it. Second, they didn't announce that all neutrino's move faster than the speed of light (which is what you seem to say), all they announced was that their result showed that neutrino's of a few different energies travel a large distance slightly faster than light would. They don't claim anything about the neutrino in general, and more importantly, they actually ask people to try to disprove their results, because it would have such a big impact if they turned out to be true.


Basically what happened:
- Scientists generate neutrino's and steer them toward a detector over 730 km away.
- The detector detects them and measures how long their journey was.
- The result is that they arrive around 60 nanoseconds faster than light would, meaning they traveled faster than light.

Faster than light travel by a massive particle (massive as in "it has mass" not as in "it's heavy or large") is strictly prohibited by special relativity, it's (a result of) one of the fundamental postulates and it's widely agreed as a valid theory. Special relativity is one of the most tested theories today and has passed every test extremely well, so as far as we were concerned (up until now) it was right.

Now, we can't be sure... If their results are true, we might be at the cornerstone of some very new physics. Either special relativity is completely wrong (which is hard to imagine seeing how accurate it has been in predicting so many things) or neutrino's are tachyons -- hypothetical particles that must always move faster than the speed of light (much like ordinary particles must always stay below it). Tachyons are completely hypothetical, the only reason they 'exist' (theoretically) is because "the math allows it". In the equations for special relativity, a particle with mass moving over the speed of light gets an imaginary energy (due to a negative root), which is generally agreed to be non-physical and doesn't exist. However, one can 'cancel' this imaginary result by allowing the mass of the particle to become imaginary. In that case, the energy is real again and, assuming an imaginary mass is physically meaningfull, would be a perfectly valid result. As far as I know nobody has any clue what an imaginary mass might mean, and my own opinion is that it's bullocks... Why allow an imaginary mass but not an imaginary energy? That seems arbitrary.

Either way, if neutrino's are tachyons, we have some explaining to do in nuclear physics. As far as I know neutrino's were postulated in the first place to exist because there was an imbalance in momentum resulting from nuclear fission (I think), so a new particle was 'invented' with a very small mass and (thus, to compensate) extremely large speed, to balance the momentum. Later it was found this was right on track and neutrino's were detected in other experiments too.
However, if a neutrino would be a tachyon, with imaginary mass, the momentum balance is again unbalanced. Well, at least I think so, how do you factor an imaginary mass into momentum? I have no clue...


A bit more explanation:

As far as I understand it, they generated a 'batch' of neutrino's (subatomic particles) via proton collisions. The particles that result from such a collision are electrically charged which allows them to be 'steered' toward the detector, over 730 km away. These particles then decay into neutrino's, amongst others, a small percentage of which will move in the same direction as the original particles.

The neutrino's travel right through the earth (there is no 730 km tunnel) and arrive at a detector somewhere in Italy I think, where they are detected. They can travel through the earth because they hardly interact with ordinary matter. Usually, matter interacts mostly via the electron cloud; the chance of a direct impact (particle hitting the nucleus of an atom) is extremely small because of the sizes involved, but the electron cloud is enormous (relatively...) and this is what causes 'interaction'. Neutrino's however can only interact via the weak force which basically means they have to hit an atomic nucleus head on to interact with it. As a result neutrino's pass through virtually anything.

It must be pointed out that neutrino's are actually really common. The sun emits large numbers of them. This might cause people to think that they might have accidently detected neutrino's from the sun. But that's not true, there are three types of neutrino's and the sun neutrino's are different than these neutrino's, and somehow they can tell the difference...

Finally, it's not that they did this experiment once and published their results as quickly as possible without checking anything. No, they got their first result 3 years ago and repeated their experiment 15.000 times, just to rule out 'random' influences (time of day, season, temperature, motion of the earth, gravitational waves, a bug flapping its wings, etc) and get a statistically valid result (6 sigma I think), meaning the result was consistently (enough) in favor of 'faster than light'. (Fun note: another lab obtained a similar result (faster than light neutrino's) a while back, but they did not get this statistically valid result so it was discarded as a measuring error).


Anyway, quite exciting, but it will probably turn out their result is false. It would be exciting to find out it was true but most people seem to agree they must have overlooked something. Unfortunately, there are only two labs in the world capable or reproducing their experiment, one is in Japan and is currently damaged by earthquakes, the other is (I think) in Chicago and doens't have the required equipment (yet), so we're looking at a few years before the results can be checked.


Another cool fact I think: neutrino's are also generated by a supernova explosion, along with a bunch of light. We can detect those neutrino's, and in the past (multiple times I think) we have detected the neutrino's before we were able to see the light from the explosion! Faster than light neutrino's again? Well, probably not: it turns out that the neutrino's are generated very early in the explosion 'process', while the light is only generated at the end, when the shockwave reaches the surface. Neutrino's thus get a headstart. If you do the math it turns out the neutrino's were not faster than the speed of light in these supernova explosions. Also, if you assume the neutrino's had the (faster than light) speed measured in this recent experiment, they should have arrived years early (much larger distance!), instead of the mere 3 hours that we measured.

[NickThissen]

also, was it proved, and do you think the neutrino actually teleported.

You can't prove a scientific theory, you can only test it (which they did 15.000 times, and are now asking others to do the same) and/or proof it to be wrong.

As for teleportation, I don't know where you got that from. There is no teleportation in play (how do the neutrino's know to teleport into the detector and not 5 feet away from it or to the edge of the observable universe?), they simply measured a speed that is slightly larger than the speed of light.

Also, you cannot 'strap yourself' to a faster than light neutrino and travel back in time, as the media is trying to claim. Even if you could 'strap' yourself to a neutrino, you wouldn't experience any time travel. The only reason time travel is involved is that according to special relativity there exists inertial frames of reference (someone else moving with a constant speed, different than the speed of the neutrino) in which the neutrino seems to travel back in time, where it is detected, travels back in time and is then generated. However, if the neutrino is a massive particle and it did travel faster than light, special relativity is wrong, so there is no saying whether this still holds:wave:

[moti barski]

I reported what they said on the news.
now, if the neotrino really traveled faster than light, than it would mean
hypothesis zero
from a critical POV it could be a fake result to justify all the allocated resources that might go to who knows where, as a reader I don't personally know.

having said that, considering the teleport option, does the neutrino has some connection or special behavier with plasma ?

[NickThissen]

I reported what they said on the news.
now, if the neotrino really traveled faster than light, than it would mean
hypothesis zero
I have no clue what this means.

from a critical POV it could be a fake result to justify all the allocated resources that might go to who knows where, as a reader I don't personally know.
Oh god not this again...

having said that, considering the teleport option, does the neutrino has some connection or special behavier with plasma ?
Or this...

Ok, fake results happen, I give you that, but they are extremely rare and people always figure it out in the end, by repeating the experiment and finding different results. The clue here is that their report actually states they want people to repeat the experiment! Do you really expect them to waste 3 years and a whole lot of money falsifying results that could mean the greatest change in physics in many years, just to be proven wrong a bit later by their own invitation?

Also, what's it with plasmas and teleportation with you? They aren't related, nor are neutrino's related to plasmas. You probably still don't understand what a plasma is yet remain convinced you know how to built a teleportation machine with it?

[moti barski]

as for the teleport I'm not convinced, but it's a possible route. I remember they said they have no idea what would happen in the machine in NG channel when they built it and now this I don't know man.
at any rate if senior neutrino passed the speed of light then it would have travelled back in time (possibly) and then it would time at random arrival time or never.

also I would like to know how they made the neutrino ?
and what makes them so reliable to you nick ?

[NickThissen]

as for the teleport I'm not convinced, but it's a possible route. I remember they said they have no idea what would happen in the machine in NG channel when they built it and now this I don't know man.
at any rate if senior neutrino passed the speed of light then it would have travelled back in time (possibly) and then it would time at random arrival time or never.

also I would like to know how they made the neutrino ?
and what makes them so reliable to you nick ?

I don't think teleportation is a possible route, why do you think it is?

These experiments aren't done in the LHC.

I never said I thought the results were very reliable. I didn't check them in detail. But they repeated their measurements 15.000 times and obtained a statistically valid result. That in itself means there is a chance they might be right. But it's still far more likely that they overlooked something, or that we require only a minimal change to our theories, because allowing faster than light travel means a contradiction of special relativity, and in turn general relativity, and in turn most of physics. And physics seems to work quite well so far so that would be a little strange :)


You misunderstand what time travel has to do with faster than light speed. It doesn't mean the neutrino's would appear at a random interval.

Here's an explanation of how faster than light communication can break causality. In this case, Alice sends a message to Bob, who sends a reply back. In some cases, Alice can receive Bob's reply before she has sent her message in the first place. This breaks causality; if Alice chooses not to send her message after receiving Bob's reply, she couldn't have gotten his reply in the first place..!
http://en.wikipedia.org/wiki/Tachyonic_antitelephone

(Funny thing is that there is no scientific reason why causility should be held. Relativity and as far as I know everything else works just fine when causility is broken, but without causality... who knows what would happen... I can't imagine a universe without causality)


As to how they made the neutrino's, you can read about it in their paper:
http://www.france-info.com/IMG/pdf/opera.pdf
Figure 2 shows a basic picture.

I didn't read it in detail but I've been told that they use proton collisions, generating charged particles (kaons, pions, etc). These can be directed using electromagnetic fields (to steer them toward the detector), but they soon fall apart into other particles, including muons and neutrino's. Because their mass is so small the neutrino's keep the same direction as the charged particles that were their 'parents'. According to the paper, the beam of neutrino's is only 2.8 km wide at the detector, which is 730 km away, so the beam is relatively small (like consistently shooting a soccer ball into a 3 meter wide goal across 7 football fields)

[BlindSniper]

@Moti
Disregarding all Logic and physics.If faster than light travel causes the object to go back in time, it would never reach the other end because it would be consistently going back in time(Newtons First law of motion). Depending on how fast the object goes back in Time the neutrino might reach the recipient before it was fired or It might go back so fast in time that the recipient does not exist. If that is the case there would be no neutrinos to detect since they would all just go back to the beginning of time(if it ever had a beginning)

I'm making all this up out of the top of my head so it might be a little incorrect.

[NickThissen]

@Moti
Disregarding all Logic and physics.If faster than light travel causes the object to go back in time, it would never reach the other end because it would be consistently going back in time(Newtons First law of motion). Depending on how fast the object goes back in Time the neutrino might reach the recipient before it was fired or It might go back so fast in time that the recipient does not exist. If that is the case there would be no neutrinos to detect since they would all just go back to the beginning of time(if it ever had a beginning)

I'm making all this up out of the top of my head so it might be a little incorrect.
It is a little incorrect :)

The neutrino itself doesn't go back in time. Remember, time is relative! The point is that if an object travels faster than the speed of light, one can show that (other!) inertial frames of reference exists in which, for an outside observer, the object seems to travel back in time. In that case, an outside observer would observe the neutrino being detected before it is generated (and 'fired'). This is all a consequence of the fact that the speed of light is invariant and is the same no matter your relative speed.

If you fire a gun standing still the bullet might go 1000 kmph (I have no clue). If you fire the same gun from a plane flying at 500 kmph, the bullet would travel at 1000 kmph relative to you, and 1500 kmph relative to the ground.

With light, it does not work this way. If you fire a laser standing still, you observe the light going at a speed 'c' (lightspeed). If you fire the same laser on a spaceship traveling at half the speed of light (0.5c), you see the light going at a speed 'c'. At the same time (and this is the difference), an observer on the ground (standing still relative to you, you are moving with 0.5c relative to him) also sees the light traveling at c, and not at 1.5c.

"That can't be right", I hear you think. Both cannot be true, something must 'budge'. It is time that budges. From the observer on the ground, time on the distant space ship seems to go slower.
The first example was actually wrong: the bullet fired from the car doesn't travel at 1500 kmph but actually very slightly less. The closer to c you get, the more pronounced this effect becomes, and at speeds we experience we can hardly measure it, so we don't worry about it. I have no clue about the accuracy of the numbers but an example might be that 1000 + 500 = 1499.99999, while 0.95c + 0.95c = 0.98c.


Now consider another but similar example. Alice is standing in the middle of an empty train, which is moving with constant velocity. On the front and back ends of the train (on the inside) are light detectors. When Alice switches on a light, both detectors go off at the same time, because the light takes equally long to get to the back and to the front of the train (the distance is equally long).
Bob on the other hand is standing on the train station and sees the train zoom by just as soon as Alice turns on the light. From Bobs point of view, the back end of the train is moving toward the light source and the front end is moving away from it. Remember: the speed of light is the same for Alice as it is for Bob, even though Alice is moving relative to Bob. Thus, Bob sees the back detector light up first (because it moves toward the light source, the light has a shorter distance to travel).

While Alice detects both events (detectors going off) as happening simultaneously, Bob detects them as happening separately. Who is right? Both are right! In relativity, events happening at the same time in one frame of reference may not happen at the same time in another (equally valid) frame!


Now, finally, if speeds faster than lightspeed are allowed, there can exist frames of reference in which the detectors on the train go off before Alice turns on her light. The effect happens before its cause, and causality is broken. This is a form of time travel (or at least it allows a form of time travel, see my link to the tachyonic antitelephone above).

Quite different from what the media is trying to suggest (at least over here), people seem to think you can strap on to faster than light neutrinos and travel back in time with them, but it's not like that at all...

[moti barski]

"That can't be right", I hear you think not me :lol:

on the other hand, the neutrino didn't become energy ?

[SJWhiteley]

Put down the scifi magazines and stop listening to the media, who are becoming, by definition, ignorant.

It's all about frames of reference, as Nick has described.

My bet is that a frame of reference has been distorted by the neutrino collision such that the two measurements are not in the same frame of reference (something like using one stopwatch to measure the start event, and another to measure the stop event with the latter running 'slow' making the time difference appear to be shorter than it actually was) thus appearing that the speed is greater than it actually is. Of course, this would imply that something within the collision modified an external event...which I would suspect didn't happen.

Having said all that, I don't even know how they 'measure' such things - I'm guessing a Made in China 99c stopwatch and a wooden ruler are out.

[NickThissen]

Put down the scifi magazines and stop listening to the media, who are becoming, by definition, ignorant.

It's all about frames of reference, as Nick has described.

My bet is that a frame of reference has been distorted by the neutrino collision such that the two measurements are not in the same frame of reference (something like using one stopwatch to measure the start event, and another to measure the stop event with the latter running 'slow' making the time difference appear to be shorter than it actually was) thus appearing that the speed is greater than it actually is. Of course, this would imply that something within the collision modified an external event...which I would suspect didn't happen.

Having said all that, I don't even know how they 'measure' such things - I'm guessing a Made in China 99c stopwatch and a wooden ruler are out.
Hmm, I doubt it. I've no clue how a neutrino (nor a collision) could 'change' a frame of reference. A frame of reference isn't something you can change. Unless the neutrino actually moved the detector, or perhaps spacetime around it... In any case I think effects such as this are tiny, and a 60 ns difference is relatively huge compared to these effects.

EDIT
And even then, it wouldn't matter, right? From our frame of reference, we saw the neutrino moving at a speed v > c. That is supposed to be impossible in SR, even if the neutrino didn't move at v > c in its own frame of reference...

As to how they measured it, it's all in their report (http://www.france-info.com/IMG/pdf/opera.pdf) but it's a little technical and links to a few other articles, I haven't looked over it for more than a few minutes either so I couldn't tell you.

[FunkyDexter]

Great explanation of why relativity appears to prohibit faster than light travel. I can use this to impress my freinds while not actually bothering to properly understand it.:thumb:

you cannot 'strap yourself' to a faster than light neutrino and travel back in timePah! I think you just lack ambition. Cave Girl Orgy here I come...

[Shaggy Hiker]

my own opinion is that it's bullocks...


If we are going to make fun of Nick, let me join in: Don't have a cow, man!!

Still, we could test your theory. If the detector was a china shop....then you'd be right.

(I think the word you were looking for there was bollocks, see this link:
http://www.urbandictionary.com/define.php?term=bullocks)

[techgnome]

Having said all that, I don't even know how they 'measure' such things - I'm guessing a Made in China 99c stopwatch and a wooden ruler are out.

You just made my day with that...and after reading all those posts by Nick on the matter (no pun intended) ... much needed levity..

-tg

[NickThissen]

If we are going to make fun of Nick, let me join in: Don't have a cow, man!!

Still, we could test your theory. If the detector was a china shop....then you'd be right.

(I think the word you were looking for there was bollocks, see this link:
http://www.urbandictionary.com/define.php?term=bullocks)

Lol :blush:
At least I have the excuse that I'm not a native english speaker :lol:

[Shaggy Hiker]

I thought it was amusing that the link said that this was a mistake made by ignorant Americans. As everybody knows, we aren't native English speakers, either, though that certainly isn't the worst one we do.

[FunkyDexter]

that certainly isn't the worst one we doWearing your pants on the outside and carrying purses are fairly dodgy too.:wave:

[Shaggy Hiker]

Wearing your pants on the outside and carrying purses are fairly dodgy too.:wave:

You wear your underpants on the outside?!?!?!? Who do you think you are, Madonna???

Are purses an American trait?