February 23, 2012

"The shocking result that neutrinos apparently travelled from Switzerland to Italy faster than the speed of light..."

"... may have been due to a malfunctioning fibre-optic cable, says OPERA, the Italian collaboration of physicists that made the first, surprising claim."

36 comments:

Zach said...

With all due respect to the experimenters, it was always going to end up being something like this. I'm a physicist myself, and not a single physicist I talked to believed they had actually found something.

The experiment they were performing involved extremely precise timing (they claimed to detect a 60 ns discrepancy) to compare events which were separated by hundreds of kilometers. Worse, they didn't have a clear optical path between the source and the detector, so they couldn't do the obvious thing and send an optical pulse synchronized with the neutrino pulse in order to see which arrived first.

To most physicists, it was like getting a bank statement that claims you have 10 million dollars in your account. In principle it sounds exciting, but in practice it just means that someone screwed up somewhere.

Carol_Herman said...

It's like the old TV repairman. The first thing he did when he came to your home, was to make sure the plug was plugged into the socket.

Good for science to try to duplicate this one. Couldn't. And, then searched for the answer.

Perhaps? Perhaps, one of the scientists put his coffee cup down on top of one of the cables? Or? Maybe, an elbow?

Do cables loosen on their own? Or are they like women?

What a STUPID new ID system! Though I keep passing the eye test, it seems to be stalling the compositions ... "like a loose cable."

Joe Schmoe said...

A bad fiber-optic cable: I bet Verizon was involved. Those clowns could fuck up a one-car funeral procession.

Patrick said...

Not especially surprising, although maybe a bit disappointing, given how radically it would have to change what we know, or think we know. The initial result had a little bit of credibility, though because those neutrinos are tricky little devils.

Beautiful hypotheses, ugly facts. But, this is how I like my science. Nice and transparent.

Tibore said...

This is the way science works. If a theory appears to have holes, then repeated experiments using different approaches will demonstrate the problem. However, if multiple experiments confirm and isolated ones refute, then the isolated ones get examined more closely for problems. Which is what's happening here.

As has been pointed out elsewhere: This is a little bit analogous to the famous (in physics) Millikan "oil drop" experiment which "entailed balancing the downward gravitational force with the upward drag and electric forces on tiny charged droplets of oil suspended between two metal electrodes" (from Wikipedia). Millikan came up with an incorrect value for the charge of an electron because, very simply, he had the wrong value for the viscosity of air. Granted, that's a case of an incorrect value entering the equation, whereas this appears to be a case of unexpected equipment effects, but the overall point is still the same: It takes repeated experiments, plus rigorous examination for sources of error, to validate findings.

Relativity is one of the most rigorously tested scientific theories ever. It of course is not the final word - no theory ever is - but it's not something so weakly supported that a single experiment could overturn it. That's why so many physicists - including the ones who actually carried out the neutrino measurements - noted that the Italian findings needed to be checked and checked again. Even they knew that the experiment needed extra lookovers.

That's science. It's a bit messy, but it validates things over time.

Michael McNeil said...

What a surprise — not!

What is perhaps surprising is that so many folks instantly latched onto this supposed news that FTL occurs — whereas, the record of general relativity (the modern theory of gravity) in demolishing theoretical opponents and purported experimental failures is spectacular and ought to inspire caution among critics.

Misner, Thorne, and Wheeler put it thus in their massive tome Gravitation written decades ago — but whose point is still perfectly valid, according to Caltech general relativist Sean Carroll (personal correspondence):

“Among all bodies of physical law none has ever been found that is simpler or more beautiful than Einstein's geometric theory of gravity […]; nor has any theory of gravity ever been discovered that is more compelling.

“As experiment after experiment has been performed, and one theory after another has fallen by the wayside a victim of the observations, Einstein's theory has stood firm. No purported inconsistency between experiment and Einstein's laws of gravity has ever surmounted the test of time.”

Query: Why then bother to examine alternative theories of gravity? Reply: To have ‘foils’ against which to test Einstein's theory.

“To say that Einstein's geometrodynamics is ‘battle-tested’ is to say it has won every time it has been tried against a theory that makes a different prediction.”

JMS said...

This was not bad science. These scientists' own announcements were cautious, and they put their results and methodology out for public review.

Compare to climate science, where raw data and the methods they use to massage it are closely guarded secrets -- they even destroy data rather than answer a FOIA request.

Original Mike said...

I hate fiber optic cables. They're too fragile.

bandmeeting said...

This is not my joke but I'll provide it for the people who didn't hear it when this story first broke back in September.

The bartender says, "I'm sorry, we don't serve faster than light neutrinos here".

A neutrino walks into a bar.

Original Mike said...

Faster than light travel!!!!!





never mind

traditionalguy said...

Very interesting. This may be propaganda by Deniers who are funded by Big Light desperate to keep their monopoly on speed records.

Or it may have to do with the time delay built in to Rush Limbaugh's Radio broadcast.

Original Mike said...

"...not a single physicist I talked to believed they had actually found something."

We didn't believe it, either. Like you say, it was going to be something in the experimental setup.

Tibore said...

Oh, btw Professor: What I'm reading is that the fault may be in the cable connector. Sure, that may sound like a trivial distinction, but it's important in how it would need to be addressed. If it's the cable's "plug", then that's a minor replacement. If it's the apparatus's socket, then the question arises of whether the actual socket is actually the one responsible for delaying the timestamps, or if the "logic" (i.e. the actual circuitry, the actual electronics) controlling it is what's at fault. The first mandates a simple cable repair or swap. The second mandates a deeper dive into the measurement equipment. Maybe a physicist reading this could go into more details, but the distinction is fairly important in that it dictates what direction the researchers end up going in.

If anyone's more familiar with the equipment that was used in the experiment, please speak up. I'm only working from broad generalities; I don't know the specific equipment involved.

Original Mike said...

"This was not bad science."

This is the way it's suppose to (and usually does) work.

EDH said...

A problem with the flux capacitor, no doubt.

I'm sensing a theme: Who needs science when you've got movies from the 1980s?

Icepick said...

To most physicists, it was like getting a bank statement that claims you have 10 million dollars in your account. In principle it sounds exciting, but in practice it just means that someone screwed up somewhere.

What you do in that case is withdraw as much as possible as fast as possible and skip the country to Rio - Rio by the Sea-0....

Original Mike said...

The problems we have with fiber is a) it doesn't take kindly to bending, and b) bad coupling at the connectors. We have little condoms we put on our fingers when we're futzing with connectors. You don't want to get oil into the connection.

Icepick said...

A neutrino walks into a bar.

Nice! Somehow I'd never heard that one before.

Tibore said...

"To say that Einstein's geometrodynamics is ‘battle-tested’ is to say it has won every time it has been tried against a theory that makes a different prediction."

Yes, this. Remember when Einstein published: He pushed out his paper on Special Relativity in 1905. General Relativity was developed within a decade of that. Yet it was so prescient that it has managed to generate work for over a century, that's how good a work it is. I mean, think about it: To this day they're coming up with ways to test it and it's winning every time. Ignoring the Italian experiment: NASA's "Gravity Probe B" experiment launched in 2004 attempted to validate an element of Relativity (gravitational space-time warping), and it did so. The theory has taken all comers so far.

Yes, like I said, no theory is ever the final word. But that doesn't mean that current theories aren't correct in some fashion, whether shallow or deep, and Relativity has proved to have really fundamentally described the way the universe works. Anything else that develops down the road still has to explain how Relativity manages to describe the results that it did, just like Relativity can answer why Newton's stuff is correct in the frames in which it was developed.

It's time and "battle" tested, no doubt. And that's why Einstein (and Lorentz, and Planck, and so many others who contributed to the foundation of it) are considered great scientists. They really nailed it with this one. It's taken space travel and particle accelerators to really start to wring out the edges of a theory developed in a time when homes missing indoor plumbing and electricity were not unusual. That really says something.

Original Mike said...

On the plus side for fiber, you don't need an oscilliscope to see if you have a signal. All you have to do is look at the end of the cable.

Salamandyr said...

I don't blame anyone for having gotten excited.

The whole thing has been a wonderful example of how science is supposed to work. You know what would have been a shameful thing? If, when they first came across the supposed anomaly, they had hidden their data rather than reporting it, because it didn't match the theory.

William said...

This is a great loss for science fiction writers everywhere. Maybe if you hook up a thermal flux capicitator to the energon doohickey on the pulse generator, inter galaxy travel will still be possible.

Michael McNeil said...

Maybe if you hook up a thermal flux capicitator to the energon doohickey on the pulse generator, inter galaxy travel will still be possible.

“Inter galaxy travel” may well be possible — via things like wormholes (which falls right out of Einstein's theory). You just can't do it directly, by flying though space faster than light.

Rusty said...

Fuckin' neutrinos, always causin' trouble.

Methadras said...

Scientific method ahoy. Do some more tests. Peer review the shit out of it. Confirm or repudiate the findings. See what's left over and do them again. Hopefully, no documents will be stolen and modified by self-confessing scientists.

Harrington said...

This reminds me of the claim by Maurice Pons and associate, that they had performed a "cold fusion".
Almost immediately, what little scientific training I'd had was telling me "they'll never be able to duplicate it", and they didn't.

But for just a moment there.....

Christy said...

Althouse, as others have pointed out, this is the way science is supposed to work. I strongly object to to your "bad science" tag.

Revenant said...

For giggles, go back and read the comments to Althouse's original post about the discovery.

My favorite is still the comment that the "faster than light" neutrinos "shoot another big hole in Darwin".

Original Mike said...

"I strongly object to to your "bad science" tag."

I missed that. Yeah. She is sooo wrong.

Original Mike said...

"Fuckin' neutrinos, always causin' trouble."


Awww, it's not their fault. They can barely even interact.

Tibore said...

"I strongly object to to your "bad science" tag."

Whoa, I didn't even notice that. Professor, I don't mean to pile on, but Christy and others are correct. This isn't "bad science". On the contrary, it's rigorous science. Recall that even the researchers involved admitted that they're publicizing the findings in order to "...ask the community to scrutinise this." Those same researchers urged caution in how it was to be taken.

They weren't trying to push bad science with false findings. On the contrary, they were appealing for help from the rest of the academic community to see if someone on the outside could help identify potential explanations or sources of error.

Because of that, I have to emphasize strongly: This is not bad science. It is actually the opposite of that.

ic said...

It's refreshing to hear scientists admit mistakes instead of blaming the cabal of faster-than-light-nutrino-deniers.

Original Mike said...

"It's refreshing to hear scientists admit mistakes..."

These aren't even considered mistakes. It's a process to get to the right answer. These are steps along the way.

When we embark on a new protocol, in the first experiment (and usually the first few), we're not even looking to get a "result". We're figuring out how to "do" the experiment.

Roger Zimmerman said...

@Harrington -

The Pons & Fleischmann "cold fusion" episode is instructive on several other accounts. First, they decided (or, rather, succumbed to the U. of Utah's pressure) to publicly announce their findings prior to submission for publication - that is, prior to any official peer review. By itself, that may not have been too bad (and, it is not unlike the present situation). However, the announcement was very much a PR stunt, and lacked any scientific humility. In this respect, they demonstrated their "fallibly human" side, and clearly were hoping that they had found something real.

On the other hand, subsequent to the announcement, and I believe even prior to publication, P&F were extremely helpful to any and all comers that wanted detailed information about their setup and results. They demonstrated a genuine interest in seeing if other labs could replicate, and were not at all obstructive when the replication problems began to be reported. In this respect, they vindicated themselves as scientists.

I don't know if they have ever "given up hope". But, even if they haven't, that they held to the required practices of disclosure means that they were "doing science" all along, even if they made mistakes in the detailed implementation. Science does not require perfection; it requires a dedication to discovering the truth, including helping others to do so.

Mumpsimus said...

xkcd nailed this.

Gene said...

I think these neutrino scientists did exactly what I hope all scientists would do. They got an unexpected result. They repeated the test, checked everything they could think of about a hundred times and then published the results, saying, we can't figure this out but here's what our results are.

Now someone has come along with a possible explanation. Good work all around.