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back to article Not so fast: Italian boffins say neutrinos not faster than light

A team of 68 scientists led by the Gran Sasso National Laboratory in Italy claims to have refuted the OPERA faster-than-light neutrino result, even as the OPERA researchers are generating a new buzz by releasing their newer, more-finely-calibrated short-pulse tests that seem to confirm their original statement. Over the weekend …

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WTF?

Hang on

They just say that they are not seeing would they would expect something going faster than the speed of light would do.

However since no one is quite sure why they are going faster than the speed of light, the symptoms you get are by their very nature are unexpected. So its less refuting the evidence and more sticking their heads in the ground.

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Anonymous Coward

sort of

If the original experiment is akin to - measuring the length of a road, the departure time of cars at the beginning, and the arrival time of cars at the end, and then determining their speed from that -

What this group are doing is akin to - pointing out that along the road are lots of speed cameras, but that none of them have flashed, therefore the cars can't have been speeding along that stretch of road.

And this is a very valid point to bring forward, and is not at all the same as sticking their heads in the ground.

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Stop

For the moment, that should still be "no one is quite sure whether they are going faster than the speed of light". There are many things to check, and as the article itself states, there has been no independent replication of the results yet.

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Holmes

The feeling is...

The idea that "if neutrinos go so fast, they should radiate and slow down" was also venerable o-sensei Weinberg's first reaction, IIRC.

Now, to a layperson (like me for example), it might well make sense to say that "but you can't know that they would that". On the other hand, these people have a grasp of the mathematical constraints underlying the theory, which do not allow lego-like mix-and-match. I assume that allowing fast neutrinos to not radiate would be quite bad overall and be akin to allowing unicorns to pop up in a LHC vacuum pipe.

This story will be made into a movie with Johnny Depp and uh... James Callis. Yeah. You heard it here first.

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Actually

The way i see it is that they've measured the 'cars' and their 'fuel' but the 'cars' haven't lost as much 'fuel' as expected.

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Joke

@ Destroy All Monsters

"Now, to a layperson (like me for example), it might well make sense to say that "but you can't know that they would that"

Maybe it wouldn't be the solution, but worth doing it just for a laugh nevertheless:

Get some random company* to sue these neutrino people over their statement. Get the neutrino people to get some lawyers to defend themselves.

See what shit lawyers come up with to argue over stuff they don't even remotely understand.

*Dunno, a company that sells things with back lit LCDs. They could claim that since they used light before anybody else, other people can't do things with it too. And breaking the speed of light = YOU BROKE IT, YOU BOUGHT IT!

Don't think any company would be so vile though. Oh, wait...

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Pirate

Yes, but ...

Neutrinos are subatomic particles and can transition to other states without going through intervening states. If they transition to a superluminal state as a "quantum leap" as it were, then there would be no signs of them transitioning *through* the speed of light.

In any case, this is using established theory to attempt to disprove new experimental results. But the established theory doesn't fully understand neutrinos anyway. And since established theory forbids superluminal travel it seems odd that there is a supposed signature of such an impossible event.

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Joke

Sir

Perhaps when they exceed the speed of light they collect energy.

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Except...

Saying "we have this mathematical model for what's going on, the results don't agree with that, therefore the results must be wrong" is exactly the opposite of what scientists should be doing. Instead, they should be going "hey, that's weird, we need a new theory (once we've verified the results)"

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Indeed....

And failed to notice the cars were going downhill anyway....

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FAIL

Not so unreasonable

People not familiar with physics are making some pretty ignorant comments here. I'm by no means on the level of the guys in this article, but at least I can understand the analogy to Cherenkov radiation, so let me explain that.

Whenever we see something moving in a medium at speeds which are superliminal (for that medium) we see an associated energy release as the speed of light (in that medium) is exceeded. This is seen in the heavy water around nuclear reactors as Cherenkov radiation, for example. This is well understood physics and one of the few models we have which can apply to analyzing faster than light movement.

So what they're saying is that, according to well understood physics, when the speed of light in the accelerator is exceeded, we should see an equivalent release of energy. No energy release implies the speed of light in the accelerator (and thus c, which is greater than or equal to the speed of light in the accelerator) is likely never exceeded.

Are they right? I sure as hell don't know. But it's a pretty fair point to raise.

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@Dan

I know its a joke but can't resist anyway...

We're talking Europe here, not the US 'sue my ass of' of A ;-)

Here such claims would most likely be laughed out of court after which the person sueing is likely to be charged for slander.

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In the movies

Cerenkov radiation can either be simulated by:

a: a huge CGI budget and much pixel wrangling, or;

b: replacing the water on set with tonic water and shining UV light into the tank.

The quinine in the tonic water fluoresces blue under UV - et voila, you can have a cinematic radioactive catastrophe and cocktails.

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"And since established theory forbids superluminal travel"

AFAIK it only forbids superluminal speeds* in a vacuum, but in anything else where light is traveling at less than c then these sort of effects (e.g. Cherenkov radiation) are seen.

* Yes, I know the theory only actually forbids reaching light speed not travelling faster

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Anonymous Coward

@Not so unreasonable

It's slightly more complicated than that

Remember neutrinos are EM-neutral, and neutral particles don't produce Cerenkov radiation.

The 'analogous' part is transforming to the weak sector, where the neutrinos radiate Z bosons, not photons (Neutrinos are not weak-neutral, they are weak-negative).

However, Z bosons are massive (91 GeV), so presumably the speed of Z bosons is less than light, and hence we would be seeing this weak-Cerenkov effect even for subluminal neutrinos....?

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Boffin

Actually, established theory merely precludes the possibility of a particle _accelerating_ past the speed of light - if they start off going faster already, then the Maths works out perfectly.

In any case, one of the possible explanations is that the path these particles are following is actually shorter than they think, due to space-time not being uniformly 'flat'

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Err, not quite.

While you have to be open to the possibility of something unexpected in the experimental results, when you have a well established and repeatedly tested theory, you have to triple quadruple check your theory and your experimental apparatuses to ensure your assumptions are true and your measurements are accurate. And you really do need independent verification* of your experimental results. Only then do you have to start working on a new theory.

*The triple quadruple checking should add to the impetus for someone to perform the independent verification.

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Theory also says that they can't exceed the speed of light. If this theory is wrong, how much reliance can we place on the theory that they must lose energy in the process? What if they only seem to go faster because they somehow take a short cut?

I'm keeping an open mind, but nobody has yet found any errors in the experiment. Nowhere near 60ns that is.

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Meh

Well, the theory is generally right

Relativity is amazingly reliable in predicting results. Even if the "nothing goes faster than lightspeed" part turns out to be iffy, that doesn't mean relativity and all its ideas are automatically scrapped. Newton said [insert English -accented gobbledigook here]. In certain circumstances said pile of gobbledigook was seen to be breaking down. Einstein says [insert German-accented gobshite] that fixes the problem. But it still had to conform to what Newton said in the non-broken parts (it wasn't like Jupiter suddenly started changing its orbit or anything). So, even if we have super-luminal neutrinos, they ought to act reasonably like we expect, because any new theory has to be "backwards compatible" with both Einstein and Newton (as those two can pretty well spot-on explain what they say they explain). So, these particles ought to act like we expect basically right up until their little bald leader says "Engage"; if they are not, it suggests that they may not be actually traveling FTL It may turn out that FTL neutrinos act really weird, but the onus is on the new to prove itself, not for the old to be just ignored because it isn't shiny. I for one am hoping that we just took physics out behind the woodshed and beat the ever-living tar out of it, but after the letdown with the whole cold-fusion debacle back when I was in school, I am much more wary of being too happy before someone conclusively replicates the experiment and innately assume there was error

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Hilarious...

" [insert German-accented gobshite]"

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Actually there is nothing in the General Threory of Relativity that says that you cannot travel FTL, although doing so may have some very strange results. What the theory says is that nothing with rest mass (i.e. mass when not moving at all) can move at the speed of light. Since we cannot work out to accelerate something fromrest to >c with moving at c (even if momentarily) then FTL is basically shut out.

However neutrinos exhibit quantum behaviour, so I guess they could tunnel through the c barrier if the conditions are right. This could allow them to travel FTL, at least in theory.

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Unhappy

Theory must bow to the data

I was educated in science to follow the data. In a contest between theory and data backed evidence, in the absence of any good reason to doubt the data and evidence then so much the worse for theory. Remember Relativity has been tested by experiment, so it is not just some mathematical construct that exists perfectly in Platonic space. It also breaks down when considering very small things, like oh, neutrinos. If we are talking about a massive space vehicle or a hunk of space rock I would agree, but subatomic particles? I say Einstein may not apply here, and that is why this is interesting. So just as Newtonian physics will get you to the moon and even Mars (Demon permitting) so Einstein may be good for speeding chunks of stuff, galaxies receding from us etc but not so much for speeding neutrinos, through rock. Maybe there is some unappreciated property of the Alps? Whatever there still remains the issue of the results. They cannot be wished away by saying 'they violate theory'. If they didn't violate theory we wouldn't be discussing them. Move on and figure out what is happening.

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"tunnel through the c barrier "

My understanding of tunneling is that it can ONLY occur if the energy barrier is finite. It then becomes a question of what that means for a FTL transition

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Well does the theory also not seem to imply that if you start out FTL then FTL is the normal state and STL (slower than light) is the impossible state to reach.

I read the theory a while ago and am not a physicist (well except from the armchair), I have also not read up on neutrinos. But the first thing into my head is: if this is the first attempt to measure neutrino speed, velocity, whatever, then this means they have only detected them before.

If they have only detected them before can they say that neutrinos have ever been STL?

Now can a proper physicist please explain how badly wrong I am.

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There's another way, too. If you accept that we're living on a brane per modern string theory, it's quite possible the neutrinos are simply moving across other branes with a slightly higher value for c, or that they're closed loops moving in the bulk (and the limiting speed there is slightly higher).

It could actually be the first result predicted by M-theory.

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Anonymous John

"I'm keeping an open mind, but nobody has yet found any errors in the experiment. Nowhere near 60ns that is."

I'm keeping an open mind, and that means not jumping to conclusions based on unverified results.

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so it is , ITALY 0 - ITALY 0

NO A DRAW THEN

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Anonymous Coward

Crackpots and Fundies

The fact that a measurement which differs by only 60 billionths of a second, is enough to cause this level of debate, analysis, and scepticism amongst scientists should send out a loud message to all the astrologists, remote-viewers, alien hunters, psychic healers, and their followers...

Science (real science), is so damned precise, and current physics theories are in agreement with nature several orders of magnitude greater than can be matched by any other mystic theory, explanation, or hocus-pocus.

I sincerely hope that this ongoing debate reaches the ears of kids, and gets them thinking... about the accuracy of a physics statement, vs the accuracy of say.. a statement in scripture.

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ha good post until

>I sincerely hope that this ongoing debate reaches the ears of kids, and gets them thinking.

Must not be a merkin or would realize our kids are educated largely by bible thumping preachers and the Jersey Shore.

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Anonymous Coward

So true

Yep, it truely is amazing how exact physics can be... Almost as though it was designed to be that way by an all-seeing creator!

In other words, physics is so precise because He designed it that way.

[I would use the joke icon if icons were available on the mobile site]

Yes, I am a dedicated atheist.

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Re: Crackpots and Fundies

@Jesus Puncher

Great stuff. Spoken like a true Scorpio

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Anonymous Coward

Sadly, I think these experiments just bring more grist to their mill.

I can hear them now: "Science doesn't know everything", "Scientists get things wrong", "Come worship my god of the gaps.".

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Devil

God of the Gaps?

And yet it seems to me that some scientists are starting to consider a supernatural origin not because of the gaps, but because of what is being seen as the gaps are understood. It was a lot easier to conceive of the chance assembly of a "simple cell" when the gaps led us to believe the cell was simple.

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Anonymous Coward

I agree, but (pedantry alert)

I think you are referring to 'precision' (n the case of science) and not accuracy (in this instance at least).

I am over 1 ft tall (that is totally accurate - just not very precise).

It makes your point even better if anything - while religion is still arguing about accuracy, science is discussing precision.

Sorry for the pedantry - carry on....

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Anonymous Coward

@apjanes "it seems to me that some scientists"

Yes possibly, but presumably because youre not a scientist

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Pint

Like the Italian economy, a Mobius loop of logic

The Italian team has a "minor" logic problem. It goes like this.

If the neutrinos break the physics we know, by those known physics, we should see electron pairs!

In other words, by stepping into the unknown, the neutrino is failing to behave a it should if it hadn't stepped into the unknown.

Oh well!

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2+2=4 therefore my Mama's a shoe.

It's a bit like saying the world can't possibly be spherical and must be flat, 'cause when I put my marbles down they don't roll off.

Or possibly, "It can't have been my Jimmy what done it your honour, honest - because, well, he's not like that..."

Or a bit like trying to apply Japanese grammatical rules to Catalan, or something.

Basically, they're saying that this completely unexpected and not understood thing cannot be happening because it is not behaving as expected and in a manner we understand.

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Holmes

Shortcut

Actually, none of the experiments are measuring the velocity of the neutrinos. They are measuring the time they take to travel between two locations and deriving the velocity from those measurements. If the neutrinos take a shortcut via brane space (or any other dimension you care to mention), they can arrive faster than light without actually travelling at >light speed.

Remember that marathon runner who took a short cut? He didn't run faster than the other competitors, just got the finishing line before them.

Scientifically just as interesting, but not rewriting relativity

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@Joel

See my comment in a thread above, but it would certainly be nice if this led to the first experimental confirmation of M-theory! :)

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Happy

Grand Theory of Super-Luminal Neutrinos

Here's my untutored explanation.

All neutrinos are super-luminal. They are created across a spectrum of velocities faster than the speed of light. However, they are still subject to the quantum uncertainty principle. Thus their instantaneous position, and therefore their instantaneous velocities, are a little uncertain. Those travelling just slightly faster than the speed of light will occasionally have an instantaneous velocity slower than the speed of light. At this point they are able to interact with normal matter, and thus we can detect them through a collision with an atom in, for example, a vast tank of cleaning fluid. Those travelling a lot faster than the speed of light are lot less likely to have an instantaneous velocity lower than the speed of light, and so are lot less likely to interact. My conclusion is that the rarity of neutrino interactions is due to the rarity of neutrinos having a super-luminal velocity sufficiently close enough to the speed of light for the interaction mechanism described above to take place.

There. That's my tuppence ha'penny's worth. If it's right, please will El Reg forward my Nobel physics prize (and especially the cheque) on to me.

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Pint

Or...

I think it's because they've just been reminded by the other particles that it's their round.

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I didn't quite understand all of that, therefore you must be correct if your level of understanding is beyond mine. :-) Good theory though.

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That's an interesting idea. Now design an experiment to prove it :)

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Hmm, let me see if I understand this well.

Now two research groups are chasing funding for analysing the same data?

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Trollface

ICARUS are just jealous...

... that OPERA discovered warp drive and not them.

If we're doing untutored scifi explanations for Nobel prizes, try this one I came up with immediately after the original reports.

The neutrinos are indeed not travelling faster than C in space. Most of the time they don't interact with matter since matter is generally sparse. If they intersect ("smash into") a particle of matter you would expect other sensible particles to interact with, perhaps they appear to skip over it instead of smashing into it, using some quantummy Newton's Cradley magic smarties tube probability thing where the original neutrino becomes part of the particle and an equivalent neutrino "pops out the other side" of the field and Heisenberg strangles his cat. If that quantummy field jumping thing can happen at > C, then perhaps that is where Robert becomes your uncle. At other times (sometimes) when they smash into matter, they do whatever it is they do that is detectable.

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Like AmanFromMars, but humerous. I like.

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Coat

Heisenberg strangles his cat...

Funny as, but are you certain that Schroedinger is happy about this?

Sorry...

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Facepalm

I have to say I'm not certain about that.

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Supernova 1987A

See:

http://en.wikipedia.org/wiki/Supernova_1987A

In 1987, three neutrino detectors in different countries each detected a burst of neutrinos at 7:38 UTC on the same day.About three hours later, multiple telescopes observed a new supernova at ah location now computed to be at a distance of 168,000 light years away. Theoretical analysis says that neutrinos are generated in a core collapse and are not delayed as they leave the core, while light is only emitted when the shockwave from the collapse reaches the surface of the collapsing star, about 3 hours later.

These observations are consistent win neutrinos moving at the speed of light. They are not consistent with neutrinos moving faster than the speed of light. A baseline of 168,000 light years is many orders of magnitude longer than the baseline from CERN to Gran Sasso.

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Anonymous Coward

These observations are also consistent with neutrinos travelling faster than light at, say, the beginning of their journey before transitioning to sub light speeds.

The 2 experiments performed by OPERA might be incorrect or might be correct, that has still to be determined, but supernova 1987A only tells us that for the vast majority of the distance the neutrinos travelled they were not travelling faster than light. If it turns out that OPERA is correct then a new theory will have to be devised that is consistent with both OPERA results and supernova 1987A.

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