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 …

[JOKM]

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.

[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.

[ScientologyIsACult]

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.

[DJ Smiley]

Indeed....

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

[Eddie Edwards]

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.

[Chemist]

"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

[The First Dave]

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'

[Sorry that handle is already taken.]

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.

[Destroy All Monsters]

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.

[DAN*tastik]

@ 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...

[Sir Runcible Spoon]

Sir

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

[Anonymous Coward]

@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.

[Thomas Davie]

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)"

[Tom 13]

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.

[Arthur 1]

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.

[Anonymous Coward]

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.

[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....?

[Anonymous John]

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.

[Phalamir]

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

[Dan 10]

Hilarious...

" [insert German-accented gobshite]"

[Muscleguy]

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.

[Anonymous Coward]

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.

[Chemist]

"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

[Ragarath]

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.

[Arthur 1]

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.

[Sorry that handle is already taken.]

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.

[someone up north]

so it is , ITALY 0 - ITALY 0

NO A DRAW THEN

[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.

[asdf]

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.

[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.

[albaleo]

Re: Crackpots and Fundies

@Jesus Puncher

Great stuff. Spoken like a true Scorpio

[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.".

[apjanes]

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.

[Anonymous Coward]

@apjanes "it seems to me that some scientists"

Yes possibly, but presumably because youre not a scientist

[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....

[Jim O'Reilly]

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!

[Stylee]

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.

[Joel 1]

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

[Arthur 1]

@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! :)

[bazza]

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.

[jonathan keith]

Or...

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

[Gary F]

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

[Eddie Edwards]

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

[All names Taken]

Hmm, let me see if I understand this well.

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

[Reg. Blank]

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.

[BristolBachelor]

Like AmanFromMars, but humerous. I like.

[Dan 10]

Heisenberg strangles his cat...

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

Sorry...

[Reg. Blank]

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

[another_vulture]

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.

[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.

[Eddie Edwards]

By my calculations, if the CERN experiment was reproduced in nature in 1987, the error in your "about three hours later" would be 778s or 13 minutes (scaling up 60ns over 730km, or 2.4 light milliseconds, to 778s over 168,000 light years).

Your assertion that these observations are *not* consistent with superluminal travel relies on you having a model of the collapsing star precise enough that you can predict how long the shock wave takes to reach the surface of the star to within about 6%.

This relies on you knowing the size and composition of a star 168,000 light years away to some degree of accuracy. So how do you measure that?

Sorry, I don't think you've proven anything here, at least until you qualify the phrase "about three hours" with some level of measurement error.

[Chemist]

"ize and composition of a star 168,000 light years away "

Well try this - for our local star - on average it takes many,many years for a photon, once generated as a gamma ray, to escape from the sun due to the dense interactions in the core.

[Anonymous Coward]

Re: Eddie Edwards

"By my calculations, if the CERN experiment was reproduced in nature in 1987, the error in your "about three hours later" would be 778s or 13 minutes (scaling up 60ns over 730km, or 2.4 light milliseconds, to 778s over 168,000 light years)."

Your calculations are wrong. If you multiply 60ns by 168,000 light years divided by 730km, you get over 4 years.

[Liam Johnson]

@another_vulture

And you are mentioning this just in case the guys at CERN don't read wikipedia?

[Hand1e]

Measuring the speed of one set of neutrinos doesn't really say much about the speed of another set of neutrinos.

[Anonymous Coward]

@another_vulture apparently the neutrinos from OPERA are several orders of magnitude more energetic than those produced in a weedy old supernova. That *might* account for the difference in behaviour. Of course I no idea why that may be, but then no-one else does either :)

[Anonymous John]

Most of that 168,000 light years is "empty" space. You could hypothesise that neutrinos only exceed the speed of light ot tale a short cut in the presence of mass.

While |I'm keeping an open mind, there are three indisputable facts.

1) We can measure distances of hundreds of miles to with a few mm,

2) We can measure time to better than 60ns.

3) After several months, nobody has come up with a plausible refutation of the Opera results.

[Rob Dobs]

lots of guessing here and not much proof

One could as easily say that the neutrinos moved faster than light and reached us first, and that the light traveled at light speed, taking 3 hours to reach us.

Since we only have the detection of the neutrinos, and the light reaching us, how do we guess that this supernova took 3 hours? I would expect something like this to take more like 3 seconds. Even a shockwave should travel fast enough to reach form the center of a star to its edge in faster than 3 hours? And why was the light not released, did the shockwave somehow contain it, only releasing it 3 hours later?

Sounds like excuses, not proof. Also seems to be to me more solid proof that Neutrinos travel faster than light, as they were proven to reach us 3 hours before light in the even of a supernova.

[Chemist]

"only releasing it 3 hours later"

Photons interact STRONGLY with matter - that slows them down - that's why light travels slower than c in matter

[Reg. Blank]

Dude/Babe!

Last night I was going to mention the supernova as an event possibly confirming the Newton's Quantum Smarties theory, but thought I had written enough. I certainly had that in mind after the initial report last month.

[Anonymous Coward]

Have they overlooked the obvious?

In 57.8 nanoseconds light travels 17.3280040724 metres, or 56ft 10" (and a bit)

Rather than travelling faster than light, could they have just measured the distance wrong?

[Anonymous Coward]

By Jove I think you've got it! The answer was staring us in the face all along. Maybe you should contact CERN with this 'distance-is-wrong' theory, they might not have thought of it!

[Anonymous John]

No.

Have you ever known the GPS in your car to be 56 feet out? The distance measurement will be accurate to within 40mm. Surveying is a precise science.

[Anonymous Coward]

> Have you ever known the GPS in your car to be 56 feet out?

Pretty much all the time.

GPS receivers need accurate clocks to correctly calculate their position. These are expensive so the GPS in cars use other means to make corrections. This includes the fact that you are in a car so the navigator assumes you are on a road and places you there.

The GPS receivers used by OPERA would have been a lot more accurate than you cars GPS.

[Liam Johnson]

@Condiment

I will agree that a car might be more than „56 feet” out, but this is usually due to buildings or mountain getting in the way, and not a specifically error GPS.

AFAIK, the GPS receiver does not need a particularly accurate clock to calculate the position; the accurate clocks are in the satellites. Any local clock is synchronized to the satellite clocks after all calculations have been done to account for their speed and position.

[Anonymous Coward]

They may have, just possibly, measured the time it takes photons to travel the same distance.

[Ian Michael Gumby]

Ok... So lets see if I got this straight...

Its not an issue of something going back in time. Its a question of something moving faster than the speed of light?

OK... so if that's the case, it kind of makes sense if you consider that space can be warped, right?

Imagine if you draw a curved line. To draw the curve you need to have 3 points. Now draw a straight using the end points.

If light travels along the curve and it takes time X, while the neutrino takes the straight line path in time Y, then the neutrino will arrive at the end point before the light. If space can be warped by gravity, then light has to travel along the edge of the warp, right? Neutrinos? Not so much.

Sure this is a bit of an over simplification. Yet the mechanics of the neutrino aren't really well known, are they?

[Anonymous Coward]

no

the shortest path between two points is the path travelled when travelling at C.

it is not simply a case of drawing a hill and saying that light has to go over the bump, but neutrinos can cut through the middle. If it was a shorter path to cut through the middle, then this is what light would do (assuming it travels at C).

it is also worth mentioning that gravity too travels (propagates) at the speed of light (C), and not a bit faster or slower.

saying that the mechanics of neutrinos arent well known can't magically allow them to do all sorts of things. I mean afterall, the mechanics of a neutrino are known enough so that they can be launched, and detected, and controlled, in extremely precise ways... otherwise it wouldnt be possible to measure them in the first place.

[Ian Michael Gumby]

@AC are you sure?

Call me silly. There's all these nice theories about warping space and creating worm holes.

Basically what you're saying is that they are all fairy tales and that the universe is static and space through out the universe has the same density. Sort of a world is flat kind of statement, right?

The point I am trying to make is that if neutrinos aren't affected by gravity and gravity can bend space. then its possible that neutrinos will travel along their original path unmolested by gravity.

Its not some mythical or magical property that I assign to a neutrino. Clearly something happened.

Because you know some of the properties doesn't mean you know all of the properties. But since you're so smurt, why not tell us what the neutrino tastes like?

(The answer is chicken, but I'll let you ponder why that is....)

[Anonymous Coward]

Re: @AC are you sure?

"The point I am trying to make is that if neutrinos aren't affected by gravity and gravity can bend space. then its possible that neutrinos will travel along their original path unmolested by gravity."

In that one sentence, you demonstrate that you simply don't know what gravity, in the General Relativity sense, is.

Firstly, gravity doesn't bend spacetime. The phenomenon of gravitation is the manifestation of spacetime curvature. In a sense, the curvature of spacetime is what gravity itself is. (Energy/mass curves spacetime.)

Secondly, there is no force of gravity the way Newton described. An object in free-fall, in a gravitational field, accelerating relative to some other object elsewhere, doesn't actually have a gravitational force acting on it. It's following a geodesic, which is essentially a straight line on a curved surface (such as a line of longitude). Since spacetime is curved, different geodesics appear curved relative to each other.

Imagine two people standing on the equator, a mile apart, both facing north. They start walking north, straight to the north pole, at the same speed. They start off walking parallel to each other, but soon start to gradually converge. Each sees the other follow a curved path, curving towards them, while walking a dead straight path themself. Gravity's much like that.

So, if a neutrino follows its "original path unmolested by gravity", it will be following a geodesic in spacetime, just like everything else inertial, including light in a vacuum and the sausage on a fork seen in the opening titles of Grange Hill. The difference between being affected by gravity, and being left "unmolested", that you imagined might exist, simply doesn't exist, since gravity "works" by there not being any such difference anyway.

[Paul Landon]

Speed Of Gravity

"it is also worth mentioning that gravity too travels (propagates) at the speed of light (C), and not a bit faster or slower."

Erm no actually.

Put simply, if the direction of the force of attraction was in the direction of where the 2nd body was a finite time ago orbits would describe a completely different behaviour. Orbits would be unstable.

Similarly if the magnitude of the force was a function of the distance d/c ago then it would be easily observable especially with highly eccentric orbits.

Highly accurate measures of this have been done on the Sun-Moon-Earth system and others.

http://metaresearch.org/cosmology/speed_of_gravity.asp

[Anonymous Coward]

@Speed Of Gravity

You are talking nonsense.

A static gravitational field in general relativity does not suffer from either aberration or positional-retardation. There is not a self-consistent gravity theory in which gravitational interaction propagates at a speed other than the speed of light!

[Paul Landon]

@AC re:Speed Of Gravity

Exactly: No aberration ,no positional-retardation.

www,metaresearch.org/cosmology/speed_of_gravity.asp

The direction of the vector of the attraction is in the direction of the instantaneous position of the other body (as accurately as has been measured).

[Anonymous Coward]

@Paul Landon

Yes, I have read it. And it was interesting actually.

But if they are going to overthrow general relativity (which is based on the assumption that gravity propagates at C), then quite a bit of evidence will be needed!

http://news.bbc.co.uk/1/hi/sci/tech/2639043.stm

[John G Imrie]

Good thinking

You also have to take account of the act that gravity fluctuates across the earths surface, and that caused Eddies in the Space time Continuum.

Personally I thing the answer is 42 and we will discover that Douglas Adams' typewriter was made of neutrinos.

[wheel]

Not quite

One of those funny things about space time is that the 'curved' path that light takes is always the shortest path between two points. If the neutrinos were to follow the 'straight' path they'd have to travel further.

As an analogy, imagine two hikers who encounter a steep hill in the middle of a plain. (The hill is, improbably, taller than it its radius.) One decides to take the 'straight' path, which involves climbing up the hill and down the other side. The other decides to take the 'curved' path and walks around the base of the hill before continuing his/her journey. The 'straight' hiker actually travels further than the 'curved' hiker because of the way the plain has been warped by the hill.

[Ian Michael Gumby]

@Wheel

Lets try this again.

You wrote:

"One of those funny things about space time is that the 'curved' path that light takes is always the shortest path between two points. If the neutrinos were to follow the 'straight' path they'd have to travel further."

Ever heard of a black hole? ;-)

Here's a couple of links that talk about gravity's effect on light:

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/961102.html

http://sci2.esa.int/interactive/media/flashes/3_7_1.htm

The point is that gravity has an effect on the path taken by light (photons) and matter. Except that neutrinos don't seem to be effected by gravity.

If space is curved because of gravity, and all things (light, gravity, and the neutrino) are all traveling with the same velocity (c) ... you should be able to calculate the effect gravity has on the path traveled by the light/photons.

The point is that if this holds true, you can come up with a value on how much gravity would be needed to bend the light. (And yes, we know gravity can bend the path light takes.)

So one of the smart math Boffins could easily come up with a calculation and numbers to validate this idea.

Assuming of course neutrinos aren't impacted by things like gravity.

[Anonymous Coward]

[quote]

Everything is affected by gravity. Gravity warps of space-time according to the Einstein Field Equations, and travelling on "geodesics" (shortest path curves) on that curved surface is how gravity is manifested.

Thinking as though there is some sort of euclidean space underneath the non-euclidean space-time in which neutrinos can take a more direct "straight line" between the points is not at all supported. Everything we know of travels on this curved spacetime.

Also, speaking more Newtonianly, neutrinos do seem to have mass in the more classic sense.

[Chemist]

"Except that neutrinos don't seem to be effected by gravity."

Why do you keep repeating this - there's no evidence whatsoever that it's true !

Even photons with no rest mass are affected by gravity as predicted by GR

[Ian Michael Gumby]

@Chemist...

You have an empiracle test where neutrinos hit the target before they were anticipated to have hit.

Are they moviing faster than C?

Or are they traveling on a shorter path?

You seem to believe you're an expert on this topic so you tell me.

Btw, did you bother to read the two links I posted?

I'll try to explain this one more time... Draw two points A and B. Draw a straight line connecting A and B. now draw some point C that is in between A and B but does not lie on the line. You can now draw a curve ACB. The curve represents the path of space so gravity, light, etc... Travels along that path.

Now if neutrinos are not effected by gravity, then they will travel along AB. Assuming GR holds true and C, the speed of light is truly a constant the if what I postulate holds true, you can calculate the effect of gravity on ABC and and explain the timing issue sen at CERN.

Btw, someone already explained about photons having mass..

[Anonymous Coward]

Re: @Chemist...

"I'll try to explain this one more time... Draw two points A and B. Draw a straight line connecting A and B. now draw some point C that is in between A and B but does not lie on the line. You can now draw a curve ACB. The curve represents the path of space so gravity, light, etc... Travels along that path."

What do you mean by "the path of space"? Is the paper itself space, and the curve a path through it? Or is it only that curve that's space?

"Now if neutrinos are not effected by gravity, then they will travel along AB."

If the paper is space, and you're imagining that spacetime curvature is that paths through it are curved like your ACB curve, then you've simply got it wrong.

Spacetime curvature is where the piece of paper itself is curved, like the surface of a ball or saddle. Try to draw two, straight, parallel lines on such noneuclidean paper, and they'll diverge or converge instead of remaining parallel. Lines of longitude are an example of this. The lines are dead straight, in the sense that someone walking along them wouldn't veer left or right, yet they're parallel at the equator, and converge towards the poles.

With curved spacetime, it's not a case of light, etc, following a curved path like your ACB curve. Instead, light, and everything else moving inertially (no externally applied forces acting on them) follows a straight path, straight from A to B. Just like walking all the way along the Greenwich Meridian from the north pole to the south pole.

But if, instead, you mean that only your ACB curve represents space, rather than the whole sheet of paper, then what you're suggesting is that the neutrinos are leaving space at one point, A, and re-entering space at another point, B. That's not simply a matter of neutrinos not being "effected by gravity" [sic], it's something way beyond that.

[Chemist]

"You seem to believe you're an expert on this topic.."

I don't need to tell you anything - you already seem to know it all

As for Are they moviing faster than C?

Or are they traveling on a shorter path?

Until the experiment has been repeated by independent labs using diff.equipment then there isn't anything to explain.

As several other people have pointed out your understanding of GR's explanation for gravity is deeply flawed.

[Rob Dobs]

You can also draw a CAT

You can take enough points and connect the lines and make a cat out of it, but that doesn't mean the universe is shaped like a cat, or that milk will help you travel through time.

string theory is bullocks. Sure if you fold a string, you can make the two endpoints closer. However what sci-fi shows seem to miss is that in order to do this real 3 dimensional space, you would have to fold the entire universe in half (no easy feat to be sure)

Besides the points will make a triangle, not a curve.

Much simpler explanation, C is not a constant and yes things can move faster than it.

Christ even "light" is ambiguous. I really doubt that the light from a sun, a LED, UV light, and glowing coal ember all have the same exact energy pattern and move all exactly the same. I would bet there is some variance in their signature/movement.

[Winkypop]

Why I love science

It's exciting

It's interesting

It's dynamic

It's, it's ......not Woo!

[Anonymous Coward]

Can't they just...

... Shine a torch down the same tunnel, and see if it's detected 60 billionths of a second earlier too.

Fire a particle that travels at C down the tunnel at the same time and see which one wins the race or summat.

It seems to me that the reality is that no-one yet can prove that the equipment is really that accurate.

[Anonymous Coward]

@Jubbles:

There is NO TUNNEL. Neutrinos do not interact with matter, so the planet may as well not be in the way. They can barely detect the ones they do spot. With the revised experiment, they have been generating neutrino beams every 524 nanoseconds for 2 weeks (2 trillion events) and detected 20 neutrinos in Italy.

The real problem is that OPERA does not have a detector at the source as well as at the destination so that events could be correlated (you would have to have far more events to get a statistical match, though). Other experiments (including FermiLabs) will have dual Neutrino detectors (although if the neutrinos start out skipping through other dimensions you possibly could never detect the neutrinos at the generation point).

[Ross 7]

Re: Simon Blakely

That's one of the two big issues I have with the experiment. I know the second run with larger gaps was meant to "fix" it, but the issue is still there. They release neutrinos at one end, they detect neutrinos at the other end. Trouble is, they have no way of knowing if the neutrinos they have detected were created at the other end of the experiment, or somewhere light years away.

They can easily throw out the detections that arise when they don't expect to receive neutrinos from the experiment source, but it's not a great method. They're basically picking the results they want - not because they're dodgy scientists, but because that's all they can do. Doesn't make it solid science though.

The other problem is that gravity affects time, and the Alps aren't exactly uniform. The variations in mass of the rock they pass through will have an effect on the results.

[Heironymous Coward]

nice try, but no..

There's no tunnel, the neurinos are going thru solid rock because they can and do.

[Anonymous Coward]

tunnel?

Unfortunately there is not a tunnel, because it is not necessary for neutrinos

[MacroRodent]

They shouldn't go even at c!

I wonder why it never is discussed that even a neutrino going at exactly the speed of light should be impossible. They are thought to have mass, therefore Einstein says (if I remember my high-school physics correctly) that at light-speed the mass should be infinite. Of course it can go at so close to the speed of light that the difference is very difficult to measure.

If a faster-than-light speed is fed to the same relativistic equation, the mass is no longer infinite, but is imaginary. Not sure if that makes it more or less plausible.

[Joel 1]

you forgot about photons

According to your description above, light shouldn't be able to travel at the speed of light, as photons have momentum, and momentum=mv.

Yet photons travel at the speed of light. The explanation is that there are two concepts of mass - resting mass and relativistic mass. Relativistic mass is the mass of a body that is moving. Photons have a resting mass of 0 but a relativistic mass when travelling at light-speed.

Using E=mc^2 the relativistic mass of a moving photon is E/c^2 so directly related to the energy of the photon. So it is probable that neutrinos have a resting mass of zero, and a relativistic mass related to their energy.

[Ragarath]

Or perhaps the resting mass of the neutrino is actually a minus resting mass thus allowing it to go faster?

Armchair physics wins :)

[Anonymous Coward]

not sure of these concepts

Resting mass? - I think we call that rest mass, more syllables is not equal to more clever.

Relativistic mass, erm, momentum? - the photon has a mass-like property, inertia, but this is better described as a momentum - where it is not general mass, but energy in a defined direction.

Neutrinos are thought to have some non-zero mass, otherwise they would not be able to "mix" between different types, in-flight. The evidence for this is pretty incontrovertible. I don't know if anyone has considered imaginary mass as being a component of neutrino mass, introducing "i" is a bit of a contagion, we get imaginary forces and all sorts of rubbish. this is fine if it keeps itself to itself, but i^2 is minus one, therefore any cross-interactions in this orthogonal space are real, and should be seen already.

On the original point though,

the whole point about neutrinos is that they do not interact because they are "not here", not much of the time anyway. they look like the oscillate above and below our brane, very briefly punching through it. Therefore any Cerenkov-like pair-production process might well not occur.

[John G Imrie]

If the mass is imaginary...

Doesn't that mean that it's being bled of across more dimensions than the classic 3.5 that we directly observe?

[Gordon 10]

Another flaw

My understanding of the Italian argument is that they believe the neutrinos accelerated to C+ during transit.

If however they were already travelling at C+ at CERN then any radiation would have already been produced beforehand.

[D.R.S.]

@Jubbles

Nah - it's not a tunnel. It's solid rock. Neutrinos don't worry much about stuff like rock (or stuff in general).

[Ken Hagan]

Re: rock

You say that, but a perfectly plausible explanation of the OPERA result might be based on the realisation that they *do* worry about rock. Which means that geologists can use this method to X-ray the Earth, tomography style.

[Anonymous Coward]

a bit puzzled

I am a little curious that these scientists suggest neutrinos should have lost energy reaching 'superluminal' speeds.

I thought the whole controversy couple of weeks back was that it was *impossible* for anything to go faster than light? So on this basis, how can you have faith in predictions of what would happen if you did, based on the same accepted physics which says you cannot (and which are thus proven to be lacking somewhere)?

Using the car/road analogy given earlier above, surely the most plausible explanation if you reached the destination early but did not trigger the speed cameras (or use as much fuel as expected) is that you took a short cut? I am fairly sure such things are not beyond the realms of multi-dimensional space, and would mean that the speed of light is not exceeded, even if one apparently arrives at the destination early. Keeps everyone happy.

[Richard Fletcher]

Berlusconi

Here's an idea, maybe spacetime itself is bent in italy, in order to accomodate the crookedness of Berlusconi.

[Lord Elpuss]

Italians

I'm just surprised they didn't conclude the neutrinos were going backwards, and in complete disarray.

[Anonymous Coward]

conspiracy theory

what if the the US military spoofed the GPS atomic clock to stop other people deploying precsion guided bombs and the scientist have inadvertantly found them out?

[phuzz]

Because then the measurement of the position of the other end (CERN) would be wrong as well.

Good question though.

[Anonymous Coward]

Commercially available GPS receivers won't work for "precision guided bombs" They all have an altitude limit (18 km) and / or a speed limit (500 km/hr) such that they stop outputting position information (even though it is still technically possible to receive them)

Some implementations use 'or' , some use 'and' For instance in high altitude ballooning you need something that works at more than 18km but speed is low so 'or' logic is required. Unfortunately some GPS manufacturers don't make it obvious or even publicise what they use.

Also GPS blocking is routinely tested. The UK / NATO were doing tests off the North of Scotland earlier this year.

I'm betting on them measuring the distance wrong. They should get a long tape measure made, find a flat bit of land to do their experiment, and measure it for real :)

[Khaptain]

Just out of interest

1st Question : How do you mesure 1/60 000 000 os a second ? Do Casio make such a watch..

2nd Question : How do you mesure that accuracy of your fine piece of horlogerie in question 1 ( No, not the Casio).

[Anonymous Coward]

RTFP

Read the fucking paper

[Anonymous Coward]

There's a joke in there somewhere

About the irony of Italians, measurement of speed, tanks and 5 reverse gears but I'll be damned if I can see it so early in the morning.

[Anonymous Coward]

What coordinate system do they use?

If the universe is expanding and the speed of light is a constant then all measurements should be relative to the stationary spot at the centre of the universe. (Assuming the centre of the universe is stationary of course, and on re-reading this response before posting I realize that I have no way of proving that it is).

At the time of the experiment Gran Sasso will be moving towards Geneva at some velocity (which may be negative), and 12 hours later Gran Sasso will be moving away from Geneva at approximately the same velocity (All measurements taken relative to the centre of the universe)

That being the case I would expect that if neutrinos travelled at a fixed absolute speed which is close to c and the measuring equipment was accurate enough they would get consistently different results depending on time of day.

Does anyone know if they have done this?

Or am I being too Newtonian?

[CoffeeFueled]

Re: What coordinate system do they use?

Except that relativity implies there is no stationary point, or at least that there's nowhere to tell where it is. That's kind of the point of having no special frame of reference.

[Justicesays]

Imagine a balloon

With lots of galaxies and stuff floating around on the skin of it, in a 2d layer, and call that layer a "universe".

Now consider the expansion of the "universe" is caused by the balloon getting inflated,

Where is the "center" of the universe that lies on the skin of the balloon, and how would a 2d "skin dweller" get there?

Now just add a dimension (or 7, or 9, or however many extra small ones they need atm) to approximate that question in our 3d-ish universe.

[spider from mars]

uh..

guys, this news is over a month old. The ICARUS study was published on the 17th October.

[Mars]

Yeah, I was thinking the same myself. Deja-news all over again. This paper hit the news quite a while back, and for some reason has suddenly hit the news again. My bet would be that someone sent out a press-release.

It's 99% certain that the OPERA result will turn out to be an artifact of some sort - and I'm sure that virtually everyone involved at OPERA think the same thing. It's just that they don't know what that artifact actually is, and they want to find out. My bet would be that it'll turn out to be a problem with synchronising the time between the two locations.

[Anonymous Coward]

On the other hand.....

This is one of those situations where you have to throw the rule book out of the window: it seems rather naive for the italians to expect these neutrinos to behave according to the other classical rules of physics, when allegedly they have already broken a very fundamental one!

And we await, with baited breath, a second team of scientists, in another centre around the world, to confirm or refute these results in a second, indipendent, experiment.

[Anonymous Coward]

And we await, with baited breath,

Is it mostly the laymen that are waiting with baited breath, because they have been caught up in the media nonsense, and expect that the neutrinos are actually travelling faster than light.

Anyone who has paid any attention to all the previous experiments that these results contradict is only really waiting to see in what way the Italians have made an error.

[Ken Hagan]

Re: baited breath

Dont' hold that baited breath. The yanks switched off Fermilab the other day so CERN is probably the only place where (one end of) the experiment can be hosted.

[Metz]

It's all well and good...

...but where's my damn flying car !!! You promised !!

Paris, because she promises more than she delivers, too.

[Anonymous Coward]

At least this is all good for something...

I really feel like having Lasagna or Spaghetti this evening :-)

[Tom 7]

But the still dont actually KNOW when they left.

Their assumption that the neutrinos are generated in their machinery when they think they are seems pretty sound but it is not proven.

[Mike Bell]

Lorentz

The Lorentz Transformation, 1/SQRT(1 - v*v/c*c) is what makes it tricky to get objects with mass near the speed of light. Plug v=c into that formula and you get 1 divided by zero, which throws a real spanner in the works. Infinite energy required to get there etc.

However, if v > c, you are faced with the square root of a negative number; what mathematicians call an imaginary number.

The thing is, imaginary numbers - despite their name - abound in quantum mechanics. Most of quantum physics wouldn't work unless imaginary numbers had real relevance.

Maybe that has something to do with it. I don't know.

[TRT]

Are they sure...

they are exactly the same neutrinos and not new ones in a kind of knock on effect? I mean, we have recently seen virtual photons materialise out of thin air... and sound can travel faster in a solid than in air, and electrons move in a kind of Newtons Cradle shuffling of energy... I dunno. All very weird.

[Anonymous Coward]

How about

"If there’s a better grand show than watching gold-standard peer-review play out in public, The Register would have trouble nominating what it could be."

The reaction by Evolution Believers to indisputable scientific findings made by Biblical Creationists. (Awaits cries of "but that isn't science")

[Adam T]

Questionable accuracy of prior experiments?

If the Gran Sasso boffins are right, and the OPERA data is a bust, what does that mean for other experiments made in these rather expensive facilities; past, present and future?

I mean really, they've been caught out with potentially dodgy results only because they should be impossible. How many previous results have been taken as correct, simply because they *weren't* "impossible"?

How much bad science comes from mistakes that aren't seen to be mistakes?

[Anonymous Coward]

not many

most experiments don't involve receiving data through the rock walls from another lab, so not many.

[Martin 49]

Very seasonal I thought.

"Oh no they didn't !!!"

[Chemist]

Incidently...

I've just looked at the detector web-site. The detector stack is 25 m long ! so the transit time for a light speed particle would be about 80nS

I assume the detection events are found over the entire length and then averaged in some way

http://www-opera.desy.de/pics/detector2.jpg

[Mme.Mynkoff]

Richard Chergwin

Richard wants the Faster Than Light story not to be true, so badly it hurts.

First he said it can't be true.

Then he said it musn't be true.

Can we get back to proper science reporting please?

[lforsley]

shortcut

It may be that the latest interpretation of the OPERA results, e.g., no superluminal neutrino velocity because no change in frequency misses the possibility of an interdimensional "shortcut", which may be related to neutrino oscillations as well. If so, then even before the LHC is generating sufficient collisions indicating extra-dimensions, the "walk across the Alps" will do the same. Randall, et al, will be pleased.