
Neutrino experiment affirms faster-than-light claim - Rickasaurus
http://blogs.nature.com/news/2011/11/neutrino_experiment_affirms_fa.html
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breadbox
To be precise, this latest experiment only ruled out one possible source of
error (namely, bias in the detection of arriving neutrinos causing it to
preferentially detect neutrinos at the forefront of the pulse). This doesn't
affirm that the neutrinos actually exceeded light-speed.

But it is an important step towards understanding what's happening, and it's
great that the OPERA group were able to put together this followup experiment
so quickly.

~~~
jessriedel
> This doesn't affirm that the neutrinos actually exceeded light-speed.

You might be thinking of "confirm". This certainly is an example of the OPERA
group _affirming_ their results.

> Affirm. v. 1. State as a fact; assert strongly and publicly. 2. _Declare
> one's support for; uphold or defend_.

~~~
compman775
Take a look at definition 1 in your post.

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burgerbrain
The way English works, not all of the dictionary definitions for a word need
to apply to any particular usage.

~~~
topbanana
I think all dictionaries work in this way, not just English ones

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jgrahamc
I wrote to the lead author asking them to release the source code of the
software that they used for the data analysis. I have yet to receive a reply,
but it's pretty important to eliminate a programming error from this.

For example, there were small errors in the Met Office's climate change
software that I detected. The scientific papers were correct, but the
translation into code was not. This could have happened here and it would be
better if they released the code.

[http://blog.jgc.org/2010/02/something-odd-in-
crutem3-station...](http://blog.jgc.org/2010/02/something-odd-in-
crutem3-station-errors.html)

~~~
JonnieCache
I find it very strange that the source code is not routinely released in these
circumstances. What possible reason is there for not doing so? The code and
the ideas within have no direct commercial value, surely?

At the very least it should be as available as the papers themselves.

~~~
jonhendry
Biology researchers don't get to reuse the other guy's mice, why should they
reuse their code? As long as the paper describes the algorithms used, anyone
should be able to duplicate the work using their own preferred implementation.

Also, a lot of the code may well be specific to the apparatus used, which may
be unique to a lab, consisting of custom-built hardware.

~~~
ajuc
Mouse can't be perfectly copied. Code can.

If biologists could copy mice from other experiment to give them their own
drugs and compare results, they would surely do this along with using their
own mice.

The more ways to compare experiments, the more sure we will be about results.

I understand cleaning up code is a lot of work, so don't do it, just release
it as it is. I know it will be ugly, will include obscenity, etc. If somebody
need it, it will do the rest of work.

~~~
jonhendry
"The more ways to compare experiments, the more sure we will be about
results."

No. The more exactly you duplicate the original experiment, the more likely
you duplicate any confounding issues. If someone observes something through a
telescope, it's best to verify it through a different telescope somewhere
else, to exclude the possibility of an optical quirk of the first telescope.

~~~
ajuc
Some people will run the same code on the same data. They will get the same
results, but so what.

Some other people will run the same code on different data (maybe from
simulation, or when checking their own theory). They will get some other
results, or the same.

Some people will recreate experiment from scratch, and get code B and data B.

Some people will run code A on data B. Some people will run code B on data A.

Now we can't do that. The code is already written, it's waste to hide it, it's
not like publishing code prohibit other people from writing their own code.

That's how you check for errors - by changing as little as possible and
observing results.

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davidjohnstone
The last thing I heard about this was that the results could be explained by
the researchers overlooking the relativistic motion of the GPS clocks, and
when corrected for it, the results were actually another confirmation of
special relativity. See <http://www.technologyreview.com/blog/arxiv/27260/>

That said, a brief search turned up this paper (
<https://facultystaff.richmond.edu/~ebunn/vanelburg.pdf> ) which argues that
that explanation is faulty (i.e., the paper made a mistake, and when
corrected, the original researchers' results stand).

(Disclaimer: although I once read a book on this stuff, I shouldn't be
confused with an expert, and I have no idea who's right and who's wrong. But
it is exciting.)

~~~
sliverstorm
I seem to remember when that theory was discussed, it was explained that GPS
clocks already take into account relativistic motion. Or something like that,
don't quote me, I'm not a physicist.

~~~
Confusion
I am a physicist and GPS indeed takes relativistic effects into account. GPS
would not just be slightly wrong if it didn't: it would be entirely worthless.
See for example [1].

[1] [http://www.astronomy.ohio-
state.edu/~pogge/Ast162/Unit5/gps....](http://www.astronomy.ohio-
state.edu/~pogge/Ast162/Unit5/gps.html)

~~~
jahnu
Fun fact: When designing the original system there was disbelief amongst some
involved that the relativistic effects were either real or relevant so they
built in a switch to be able to remotely disable those parts of the
calculations. They never did disable them.

~~~
Angostura
Actually, that gose down as the funnest fact that I've learned for at least a
month, so thank you.

~~~
jahnu
I don't remember for sure but I think I learned that from one of these
lectures...

"Particle Physics for Non-Physicists: A Tour of the Microcosmos"

[http://www.thegreatcourses.com/tgc/courses/course_detail.asp...](http://www.thegreatcourses.com/tgc/courses/course_detail.aspx?cid=1247)

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jarin
I seriously cannot wait for the MINOS experiment :)

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ck2
If quantum entanglement "pissed off" Einstein, I can only imagine his reaction
to this.

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loup-vaillant
If I recall correctly, Einstein was pissed of by the so called "spooky action
at a distance", namely non-local interaction. Note however that a many-world
interpretation gets rid of that.

Now we have neutrinos that may travel faster than light. That would throw
Special Relativity out the window, sure, but not the locality principle: those
neutrino do not show _infinite_ speed, unlike quantum entanglement under the
Copenhagen interpretation.

~~~
ck2
He was also upset that it appeared to violate relativity.

To his deathbed he believed in his alternate explanation that the particles
were set opposite "at birth" and initiated that way until observation (if I
understand that correctly).

So now we have at least TWO phenomena that appear to be "faster than light" -
so get cracking scientists (and engineers) on a practical application for
communications to probes that are light-hours or light-years away.

~~~
dodo53
I think generally the current theory is that quantum entanglement doesn't
allow you to transmit information faster than the speed of light as you can't
choose which state your local particle collapses into (although there's some
disagreement about whether communication could be achieved with groups of
entangled particles) <http://en.wikipedia.org/wiki/No-communication_theorem>
<http://en.wikipedia.org/wiki/Faster-than-light> (Quantum mechanics section)

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dean
Putting my tester's cap on, would it be feasible to have OPERA repeat the
experiment with photons, instead of neutrinos? Presumably, if that experiment
showed that photons travel faster than light (i.e., light travels faster than
light), it would prove that there had to be an error in the experiment.

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EREFUNDO
Will this widen the gap between relativity and quantum mechanics? or will it
actually help in finally resolving the disconnect between these two greatest
and well tested theories? Particles defying general relativity is well known,
but defying special relativity? I can see it going both ways.

~~~
hugh3
On the offchance that it turns out to be really true, it will certainly point
us in the direction of _some_ interesting new physics, so it'll be a step in
the right direction.

I'm still trying to keep my expectations down for now, though.

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csomar
I have very basic physic knowledge, and little time. I'm quite interested,
however, to know how they synchronized their timers since the Neutrino speed
is faster than light. Anyone has a short explanation or an article for that?

~~~
copper
Roughly, they used gps signals to synchronize two accurate clocks, one each at
the source and the destination.

For what it's worth, this part of the first paper is pretty accessible - at
least, as to how they did it - it's more difficult to poke holes in how
accurate it was :)

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shin_lao
It's more likely they found a particle that travels back in time than a
particle that goes faster than light.

~~~
moomin
I think that's the same thing.

~~~
JonnieCache
Yep. Relativity says they are exactly the same thing.

~~~
shin_lao
AFAIK the special relativity says than traveling faster than light will make
you go back in time, but if a particle goes back in time it does not mean it
goes faster than light.

~~~
JonnieCache
Fair point, I may have over-egged it a bit with "exactly."

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sliverstorm
I am hoping against hope...

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lwat
So we're left with what, GPS errors? I've gone through their experimental
setup and the timing looks foolproof. The only options left in my mind are

1) The distance between the labs is smaller than they think

2) Tachyonic neutrinos (not likely)

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grannyg00se
Neil deGrasse Tyson claims that another possibility is that of a new particle
moving backwards through time.

Not that I understand that.

He said it in his recent "Ask me anything" session on reddit.

~~~
EREFUNDO
Well that's exactly what will happen when anything moves faster than light, it
will travel backwards in time. The real question is where is it getting
infinite energy to break the light barrier? or are neutrinos the only
particles with mass that will not be dragged by the Higgs field?

~~~
grannyg00se
He said a _new_ particle though. So something other than the neutrinos
themselves, I suppose?

~~~
EREFUNDO
It was a neutrino that was discovered moving faster than light at CERN, that
is what I was referring to. Tyson also mentioned that it is likely a special
type of neutrino already moving faster than light is the one being observed
(tachyons). What they think we are seeing is a particle that has been moving
faster than light but never accelerated to reach that speed, it has been
moving at that velocity all the way since before the beginning of time itself.

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maeon3
What is the difference between neutrinos and regular light photons? Do
Neutrinos also exhibit the wave particle duality? Does this mean Albert
Einstein was wrong, after all these years of assuming his "biggest blunder"
was right?

~~~
neutronicus
Photons are spin one, and mediate the electromagnetic interaction. They have
zero mass and propagate at _c_.

There are actually three types of neutrino (and they spontaneously change from
one type to another), they are all spin-one-half, and they interact with other
matter only via the weak nuclear force, which has a much smaller effective
distance than the electromagnetic force, so they don't interact very often.
They have non-zero mass, but it is so small that we don't actually know what
it is.

Everything in the universe exhibits the wave-particle duality.

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rorrr
The worst kinds of bugs are the ones that only happen in production, when you
have some crazy set up with a load balancer, a CDN and/or Varnish, and a few
app servers, high traffic, middle of the day, and a bunch of executives
hovering. I have seen a crazy bug that happened only on one of the identical
app servers. Turns out SVN export didn't perform correctly (still don't know
why), and one of the files was messed up. That was not easy to find.

I have seen Apache ignore updated PHP files, and serving old code, which
should never happen. This a real bitch to debug.

~~~
sfaruque
I think you posted in the wrong comment thread...

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lobo_tuerto
I wonder if us realizing speed of light isn't the cosmic limit for everything
are like us again at realizing Earth isn't flat.

