According to this article, the team forgot to take relativity into consideration:
And:
Good article. Read the whole thing.
Also: http://www.wired.com/wiredscience/2011/10/mundane-explanations-neutrinos/
I don’t understand why what they calculate would be 32 nanoseconds “on each end”. If they’re calculating the error in the time difference between the two ends, they shouldn’t double the error. If they’re calculating the error relative to the GPS reference frame, wouldn’t the two errors tend to have opposite signs?
If this explanation is true, isn’t it a major embarrassment all round… not even for the designers/executors of the experiment, but for the entire Physics Community who should have flagged it in the first day of the uproar?
I mean: even myself, who has a vague understanding of SR, can understand the flaw immediately. So, shouldn’t any Physicist who was shown the experiment’s methods and results have spotted the discrepancy fairly easily?
I’m suspicious for that very reason–it seems like an incredibly easy mistake to catch, not only by the original researchers, but by the physics community at large. Why would it have taken weeks to catch it?
Without the Internet, how long do you think it would have taken, say, in 1910? Or 1750?
I’d like to urge caution all around. The latest news needs to be verified as much as the original news, although the chances that it will be seem greater.
I can not understand why you think this is a relevant question to ask.
I don’t take it that anyone involved in this situation is working “without the internet.”
I have no clue what they mean by “failed to take relativity into account”. The articles say that the problem is that the satellites are moving at high speed, but that effect is actually smaller than and in the opposite direction from the general relativistic effect of them being in free-fall. And the calculations to compensate for that are built into all GPS systems-- It’s relevant even for consumer use.
Frylock, I’m just suggesting that a 2-week delay in getting confirmation or refutation might be PDQ today, and equivalent to years of scientific dialogue a century ago.
How many yacht navigators need to compute their time or distance down to the neutrino level?
Corrections to the the clock rate on the GPS satellites due to their speed and their location higher in the Earth’s gravity well are necessary for them to work at all. Without the corrections, the errors would accumulate at (from memory, can’t find the number quickly) something like 100s of meters per day.
ETA: Found it. Worse than I remembered. The error accumulates about 10 km/day.
Yes, that’s what caught my eye, too… The doubling of the error seems to be rather ad hoc. Plus, IIRC, the OPERA people talked about all kinds of special relativistic corrections; I’d be really surprised if they’d overlooked this…
But, IIRC, the corrections are applied to the satellite signals periodically before transmission. My point was that the signals are sufficient for ordinary navigation, but maybe not good enough for measuring neutrino speeds without additional, finer corrections.
You were responding to Chronos’s comment that they take relativity into account. Without taking relativity into account, the signals are not sufficient for ordinary navigation.
Relativity is taken into account by the GPS system to a certain extent already, but it looks like CERN’s neutrino speed test may have required a finer calculation or an additional adjustment that was overlooked.
A general point, here: Everyone and their dog is currently trying to explain the OPERA results (either explaining how neutrinos could travel faster than light, or explaining how CERN screwed up). The arxiv is full of responses. Most of the responses are complete garbage, some are good but incorrect, and possibly, there might be one on there that’s actually correct. But it’s very difficult to tell which are which, especially for someone not working in the field. So what you’ll see is bloggers and other popular media picking replies essentially at random, and hyping them. The implication of this, in turn, is that most of the blogs you see talking about the solution to the problem are wrong.
What the heck ever happened to peer review? Sheldon came out with a paper what, six days after the OPERA report? I know he’s a Nobelist, and all, but still, does he get a free pass?
And all this “garbage,” “good but incorrect,” stuff? Obviously the incorrect stuff happens (and should happen) in any scholarship; but peers–aside from the intellectual equivalent of back scratching and price fixing–need time to God forbid think about things.
Peer review is alive and well. What did I say that made you think it wasn’t?
Simply the fact that so much stuff is being published (elect. And print?) so fast, how could p.r.be occurring?
This stuff is informal peer review. The formal process is kind of slow. In the end, only the completed works with complete peer review will count. No need to slow down the interchange of ideas in the mean time. They’ll find something wrong with OPERA results, or they won’t, and the world will change. The problem I see here is the involvement of popular media which disperses misinformation faster than people can misunderstand things. Luckily we get the Straight Dope on these matters.
Note that Chronos pointed out that most papers were on arxiv.
From the Arxiv Primer.
Theoretically, the arxiv is for material which will get published imminently. It’s a way for other scientists working in the field to get a head start on interesting results. But the papers aren’t officially published until the referees at the various journals finish vetting them and accept them.
In practice, most of the papers on the arxiv do eventually get accepted for publication, in something close to the form they appeared originally, but a lot of them don’t. The ones that don’t are a mixture of legitimate scientists who just happened not to do a good enough job this time, and crackpots. They’ve taken steps in the past few years to cut down the number of crackpots, but a few always still slip through (and of course, you don’t want to crack down too hard on the crackpots, since that would have a chilling effect on the legitimate ones, too).