OPERA review serves up a feast for physics geeks
Superluminal neutrinos and silly science writers
Let’s get the “big news” out of the way first: there’s a lot of excitement due to one paper published on Arxiv.org, which asks whether the CERN OPERA experiment – the one that seemed to detect superluminal neutrinos – took into account the “satellite reference frame” in its calculations.
So the short version of the paper is this: did the calculations conducted on the OPERA data treat the clocks on the GPS satellites as being stationary with respect to the detector (more precisely for The Register’s crowd-sourced scientific sub-editors, I mean “in the same reference frame as the detector”)? If so, van Elburg argues, it would be a source of error, because the satellites aren’t stationary; and the error he predicts a worst-case correction of 64 nanoseconds.
The media excitement is comprehensible for several reasons: the paper, by Roland van Elburg of the University of Groningen, yields a calculation quite close to the 60 nanoseconds that the neutrinos seemed to travel too fast; it would therefore restore relativity (and give journalists an opportunity for some “you was wrong!” schadenfreude).
It also suits journalists’ sense of narrative: Einstein’s theory used to prove that Einstein was right.
The most sensible discussion of this hypothesis I've seen is on the Bad Astronomy blog, here.
What the sudden leap for “Einstein still right” headlines fails to convey is the ongoing scrutiny being applied to the OPERA experiment. It hasn’t been called into question by one paper; what’s happening is an intense scrutiny that’s mostly passing unnoticed.
By my count, there have been 47 papers published at Arxiv.org discussing the OPERA results one way or another. So why just focus on one? Instead, let’s scan a few of the ideas, discussions and quirks of this “gold standard peer review” (as one reader described it recently).
Causality safe, for now
One of the first things that got everybody excited when the OPERA results first hit the wires was that the possibly-superluminal neutrinos traveled “backwards in time”. By my admittedly-poor understanding of relativity, this was mostly a journalistic construct, since in a human time-frame, the neutrinos still arrived after they left.
Nonetheless, time travel grabs the attention like few other topics, apart perhaps from climate conspiracies and crop circles. So please don’t direct any hate mail to me or to the physicists for telling you it ain’t so, at least not yet.
According to a German-Hungarian group of physicists, even if the neutrinos could travel faster than light, they can’t send information backwards in time. Their paper reminds us all that the neutrino beam would need, somehow, to be modulated. For us to be satisfied that a bit of information has been transferred, the trailing edge of the modulated pulse, not the leading edge, has to be observed fast enough to satisfy the “faster than light” requirement.
It may be, they admit, that a setup could be devised to defeat this, but at the moment, causality is safe from messages-from-the-future.
Next page: Interpreting the OPERA signal
The thing about this I'm enjoying most
is watching the process of scientific review being done out in the open
I've proven it by experimentation
This describes an experiment performed to identify how an object spinning at speeds approaching that of light can affect the measurement of other objects that are introduced into the system, and the sufficient comprehension thereof by the experimentor.
Firstly, we must identify inputs and assumptions.
Light Speed - c.
The only way I could effectively measure this is to find some light and then see how fast it travels.
The only light to hand was that inside a pocket torch.
I threw this across the room and measured it with a stop watch.
Time taken for the light to cross the room = 1.4s.
Distance thrown = 4 m.
My value for c = 2.85 m/s
The torch was broken in the experiment.
Given this value, I set out to examine a spinning object, and if I can accelerate to approaching light speed.
Through observation I identified that a spinning human will have rotational speed at the fingers approaching 2.8m/s, or c.
The experiment the proceeded to measuring something in relation to the spinning object.
This took the form of an extended tape measure and a balloon full of water passing through the air nearby (to give sufficient mass not to be affected by relativistic gravity effects).
The 2 things to be identified :-
* What strange effects are there in a spinning system approaching the speed of light.
* How confused could the experimentor become and still gather valid data.
-- Results --
The results were as expected, strange effects were observed, and the experimentor failed to fully understand the results as they were on going, requiring subsequent analysis and processing.
Firstly, the human experimentor (me) span up to the required speed holding the tape measure (extended). This gave the tip of the tape measure a measured rotational speed in _excess_ of light speed!
The balloon was then released and began its approach to the spinning object.
Unfortunately measuring the approach of the balloon was curtailed when it, inexplicably, exploded.
The experimentor is still perplexed by this. After cleaning up the water, it was identified that not all of the balloon was present. It appears that some has become converted directly to pure energy.
This will form the basis of a subsequent paper entitled "Cold Fusion from water balloons".
Given these results, I come the conclusion that strange things happen when spinning at light speed, and that I as a the performer of the experiment am unable to fully explain the results.
Dr Bo Gus (Ins. ANE)
"Richard, since this paper has been published you have been beside yourself with alarm and distress that relativity is being questioned, or not as useful as we thought:"
That's not the impression I've been getting. Perhaps the difference is that I know just how much is riding on this. Special Relativity is a purely logical conclusion forced on you if you accept the laws of electromagnetism discovered by Maxwell in the 1860s. Einstein's contribution was "merely" to point this out. (It is a measure of how painful the mixing of space and time is for most people that his contribution is reckoned by most people to be a separate discovery, and a *physics* discovery, and one worthy of a part-share of a Nobel prize.)
Prior to fixing the laws of electromagnetism, the only fundamental laws known were those of mechanics. Since settling on Maxwell's laws, the only new field to be opened up which *doesn't* depend on EM, is thermodynamics. (This goes much wider than physics. Modern chemistry is now theoretically grounded in quantum theory, as it relates to the behaviour of electrons and atoms. Large parts of biology are now explained with chemistry, to the extent that a chemistry A-level is more important than a biology one if you want to take the latter subject at university level.)
If Maxwell is wrong, the experimental measurements don't go away. You are left with a metric fuckton of results that we depend on in everyday life for which you need to explain why they are still true even though Maxwell is wrong.
You need a bloody sight more than 5 sigma on *one* experiment to persuade the community that they've been talking bollocks for the last 150 years and should start again.