Thread: Purgatory: Faster than Light Board: Limbo / Ship of Fools.


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Posted by Tortuf (# 3784) on :
 
Scientists at CERN have apparently measured particles traveling faster than the speed of light.

Of course, according to good old Al Einstein this is impossible. Or, according to Albert Einstein maybe not.

Is E = MC2 wrong?

Do we go back and start all over? That is possible given that the special theory of relativity has never been able to explain quantum physics and all the grand unification theories that base themselves on the Special Theory of Relativity either don't work, or are so complex that they are suspect on that ground alone.

And, what does this discovery say about the ability of science to describe the nature of God?

[ 05. January 2015, 20:59: Message edited by: Kelly Alves ]
 
Posted by the giant cheeseburger (# 10942) on :
 
Given the well-documented troubles that CERN has had since the LHC opened, I think the scientists should get around to checking their instruments before their stakeholders pull the funding and send them to measure they speed of an unemployment benefit queue.

Describing the nature of God? Impossible.
 
Posted by Ikkyu (# 15207) on :
 
It would be a lot of fun if the result were verified, but according to this article it probably won't be.

Wired Article

Particle physicists have been looking for phenomena that are not explained by our current "Standard Model of particle Physics" for a long time. But so far the LHC has not provided any.
 
Posted by Doc Tor (# 9748) on :
 
Like the bloke quoted in the Wired article, I'd put money on it being a systematic timing error. 60ns equates to 18m - and apparently they're relying on GPS to tell them how far apart CERN and the detector are.

GPS can be very accurate (certainly better than 18m), but there are whole host of variables involved. I'd be checking those very carefully, as well as attempting to calculate the distance using a physical method if at all possible. I'm reasonably certain that an actual survey with theodolites could have the distance down to the nearest centimetre.

But if it's all true? Egad. [Confused]
 
Posted by Alan Cresswell (# 31) on :
 
The results need to be verified. Although I'm sure they've done all they can to eliminate systematic errors, or identify instrumental causes for the observed effect, it would need independent verification. Peer review of publications describing the experimental setup and results would be a start. Repeating the experiment elsewhere and over longer distances would be essential too.

But, if it proves to be correct then it would need a major rethink of General Relativity. But the difficulties of integrating Quantum Theory and Relativity already puts both models under scrutiny anyway.

As an aside, this experiment is unrelated to the LHC. It would also be primarily concerned with attempting to determine a mass (if any) for neutrinos and whether they fluctuate between forms. The speed measurement is a bonus.
 
Posted by Eutychus (# 3081) on :
 
As usual, xkcd has the last word.

(And it will always be the last word, because since the speed of light has been exceeded,... nevermind)
 
Posted by Apocalypso (# 15405) on :
 
With the speed of light now exceeded, I look forward to being able to go somewhere and then watch myself arrive . . .
 
Posted by tclune (# 7959) on :
 
quote:
Originally posted by Apocalypso:
With the speed of light now exceeded, I look forward to being able to go somewhere and then watch myself arrive . . .
You must be a lot more attractive than I am...

--Tom Clune
 
Posted by Apocalypso (# 15405) on :
 
Or just more bored.
 
Posted by LeRoc (# 3216) on :
 
Does this mean that CERN is going to create that Black Hole now?


FWIW, I'm not getting too excited before this is replicated, but it would be very cool if it were true.
 
Posted by Doc Tor (# 9748) on :
 
Someone on another forum pointed out that the neutrino burst from a distant supernova arrived exactly the same time as the visible light - if the neutrinos had gone superluminal* by the same margin as reported here, they'd have been detected six months earlier, due to the distance of the star.


*I'd just like to point out how cool this word is, not just from a scientific point-of-view, but from a science fictional one, too. Superluminal. [Big Grin]
 
Posted by Eutychus (# 3081) on :
 
Another xkcd reader, huh? [Biased]

Someone else on the forum quoted from this fascinating article entitled "The decline effect and the scientific method", which goes some way to explaining 1) why exciting results get published 2) why they become increasingly harded to replicate.

The article concludes thus:
quote:
When the experiments are done, we still have to choose what to believe.
I have bookmarked it as ammunition for my long-runnung arts-background war with hard scientists [Two face]
 
Posted by Moo (# 107) on :
 
There was a young lady named Bright
Whose speed was much faster than light.
She set out one day
In a relative way
And arrived on the previous night

Moo
 
Posted by Doc Tor (# 9748) on :
 
quote:
Originally posted by Eutychus:
Someone else on the forum quoted from this fascinating article entitled "The decline effect and the scientific method", which goes some way to explaining 1) why exciting results get published 2) why they become increasingly harded to replicate.
Absolutely fascinating, and duly noted.
 
Posted by Apocalypso (# 15405) on :
 
Wow. That is a very interesting piece. A little frightening, but well-worth the reading.
 
Posted by Timothy the Obscure (# 292) on :
 
quote:
Originally posted by Doc Tor:
Someone on another forum pointed out that the neutrino burst from a distant supernova arrived exactly the same time as the visible light - if the neutrinos had gone superluminal* by the same margin as reported here, they'd have been detected six months earlier, due to the distance of the star.


*I'd just like to point out how cool this word is, not just from a scientific point-of-view, but from a science fictional one, too. Superluminal. [Big Grin]
Yes--now, instead of FTL drives we have Superluminal drives. It's much more poetic.
 
Posted by W Hyatt (# 14250) on :
 
I agree - it's a fascinating and important article and I've forwarded the link to my siblings and children. Thank you, Eutychus.
 
Posted by Ender's Shadow (# 2272) on :
 
Indeed the decline effect is fascinating, as is the way that scientists assume that the effect is caused by methodological problems and isn't 'real'. Which is probably inevitable - the alternative is that the rules are changing all the time which is a rather different universe from the one we're used to. But the evidence that effects do disappear does seem to be rather strong [Big Grin]
 
Posted by Schroedinger's cat (# 64) on :
 
Science has always involved faith - choosing what to believe, if you want.

The truth is, that, if this is proven to be true*, it will change one of the core beliefs of science. But then the world will adjust around this, and new theories will appear, and a new understanding of the world will be generated - including explanations of why this was not seen previously. But it will be included in the new canon of science.

* Which we will have to wait and see for. And it might be that there are reasons for this anomaly, which in itself would be interesting.
 
Posted by Boogie (# 13538) on :
 
It'll be fun if they are wrong -

Jim Al-Khalili, a physicist from the University of Surrey has said:


"So let me put my money where my mouth is: if the Cern experiment proves to be correct and neutrinos have broken the speed of light, I will eat my boxer shorts on live TV."

Bring it on!
 
Posted by IngoB (# 8700) on :
 
The decline effect is perhaps fascinating, but it sure is old news. See here the discussion by Feynman in 1974 under the appropriate label "cargo cult science". Also look here, for example at the neutrino lifetime or the omega width. If we read these plots with the assumption (!) that we are seeing a convergence to "truth", then clearly errors are terribly underestimated most of the time, and biases / systematic dependencies on prior work need decades to be overcome.

While I was still in high energy physics, we were also quite aware of the "HERA effect". That is, it was expected that every time just before its next funding round DESY HERA would report the likely identification of some exotic "new physics" particle with considerable statistical significance (generating a burst of theoretical papers), a significance that would then decay away over subsequent measurements until it was replaced by the next sensation before the next funding round... But if you think that I've just accused people of scientific fraud, then you have not understood the real problem, which is much more problematic than intentional wrongdoing.

I would like to point out though that the attempt of governments and their funding agencies to turn universities / institutes into "lean, mean science machines" is taking its toll. It may sound like a brilliant idea to take the slack out of the system. Finally, scientists that work 24/7 for the good money of the taxpayer, and all that... But the slack also provided room for error correction. A misstep now is easily fatal in particular for a budding academic career. One must ever race from one brilliant success to the other, or the other scientific rats will pull ahead. The relentless effort to reshape science into yet another "market economy" is thus having its effect. Scientific truth is becoming a commodity, mined by some, traded by others, and one shouldn't be particularly surprised if people are starting to "play the scientific market" in ways we once would have considered shocking.
 
Posted by Boogie (# 13538) on :
 
quote:
Originally posted by IngoB:
The relentless effort to reshape science into yet another "market economy" is thus having its effect. Scientific truth is becoming a commodity, mined by some, traded by others, and one shouldn't be particularly surprised if people are starting to "play the scientific market" in ways we once would have considered shocking.
Yes - and it starts way before that, in the infant school. 'League tables' at school begin the rat race. Discovery for its own sake seems to have been lost somewhere.
 
Posted by Doc Tor (# 9748) on :
 
quote:
Originally posted by Boogie:
quote:
Originally posted by IngoB:
The relentless effort to reshape science into yet another "market economy" is thus having its effect. Scientific truth is becoming a commodity, mined by some, traded by others, and one shouldn't be particularly surprised if people are starting to "play the scientific market" in ways we once would have considered shocking.
Yes - and it starts way before that, in the infant school. 'League tables' at school begin the rat race. Discovery for its own sake seems to have been lost somewhere.
/tangent

For the last three years I've taught an 'unexamined' subject, which has basically means the Senior Management Team has no interest in what I do, as long as I don't burn the school down or kill a pupil. As a consequence, we get loads of proper science and engineering done without mucking around with Success Criteria and Learning Intentions.

Gove has turned his steely gaze upon my pride and joy, and the good times may well be ending shortly...

/tangent
 
Posted by Ender's Shadow (# 2272) on :
 
Meanwhile the news that an Irish coroner has resorted to spontaneous combustion to explain the death of a pensioner is a useful reminder that there are still things we can't explain.
 
Posted by Squibs (# 14408) on :
 
While the same hubris is missing, I wonder if this wont go the way of the hype surrounding NASA's arsenic aliens.
 
Posted by Pooks (# 11425) on :
 
I come across this: Tesla. So the thought that something could move faster than the speed of light is not new.
 
Posted by nickel (# 8363) on :
 
Years ago I heard that what's "impossible" is accelerating from under the speed of light to over the speed of light. That leaves the possibility open for something that 'starts' over the speed of light. Not sure if that's true, or useful outside of science fiction, but it sounds plausible. It's a weird world sometimes!
 
Posted by Doc Tor (# 9748) on :
 
quote:
Originally posted by nickel:
Years ago I heard that what's "impossible" is accelerating from under the speed of light to over the speed of light. That leaves the possibility open for something that 'starts' over the speed of light. Not sure if that's true, or useful outside of science fiction, but it sounds plausible. It's a weird world sometimes!
I always understood special relativity as to preclude objects with mass travelling at the speed of light.

Neutrinos have a non-zero mass, therefore shouldn't be able to accelerate through c. I'm not sure of the implications for anything if CERN have accidentally invented a tachyon drive...
 
Posted by Schroedinger's cat (# 64) on :
 
The basic principle is that as your speed approaches that of light, your mass will increase proportionally. What this means is that to travel at the speed of light, your mass would be infinite, if you had any mass to start with.

Also, the speed of light is a barrier to anything whatever. It becomes significant, because we travel through time at roughly the speed of light, whereas the faster you travel through normal space, the slower you travel through time - which is why time tends to get distorted. Being able to travel faster than c through space would imply travelling backwards in time.
 
Posted by no_prophet (# 15560) on :
 
What ever happened to cold fusion? I suspect this is another spectacular result that will be soon forgotten.
 
Posted by Schroedinger's cat (# 64) on :
 
quote:
Originally posted by no_prophet:
What ever happened to cold fusion? I suspect this is another spectacular result that will be soon forgotten.
The claim to have achieved this was disproved ( or at least, not reproduced ). But the concept is still one that is being looked into.
 
Posted by alienfromzog (# 5327) on :
 
quote:
Originally posted by Schroedinger's cat:
The basic principle is that as your speed approaches that of light, your mass will increase proportionally. What this means is that to travel at the speed of light, your mass would be infinite, if you had any mass to start with.

Also, the speed of light is a barrier to anything whatever. It becomes significant, because we travel through time at roughly the speed of light, whereas the faster you travel through normal space, the slower you travel through time - which is why time tends to get distorted. Being able to travel faster than c through space would imply travelling backwards in time.
Nicely put.

One of the key things to understand is that the speed of light is the 'speed-limit of the universe.' Or rather C is the speed limit of the universe and it appears that light travels at that speed or indeed very close to it. It is not the speedlimit because light travels that fast, rather light travels that fast, and not faster because that is the speedlimit.

AFZ
 
Posted by orfeo (# 13878) on :
 
quote:
Originally posted by Ender's Shadow:
Meanwhile the news that an Irish coroner has resorted to spontaneous combustion to explain the death of a pensioner is a useful reminder that there are still things we can't explain.
'Spontaneous' combustion is actually a quite well understood phenomenon these days, ie I've seen a documentary that explains quite well how it is possible for a person's body to burn up while leaving relatively little other sign of a fire.

As for the faster than light thing... needle got stuck. [Biased]
 
Posted by Boogie (# 13538) on :
 
Some religious people revel in unexplained new discoveries as proof of supernatural forces, demons devils and angels etc.

I just think it shows how wonderfully complex the universe is and just how little we know about it, even with our incredible scientific knowledge and advances.

Surely this is what excites and motivates scientists to find out more?

The fact that it all works so brilliantly well is what blows me away.
 
Posted by ken (# 2460) on :
 
quote:
Originally posted by Doc Tor:
Like the bloke quoted in the Wired article, I'd put money on it being a systematic timing error.
Having finally caught up with what they are doing, my bet is now on a mis-estimation of the time the neutrinos are produced. You can't clock one neutrino leaving France and then the same one arriving in Italy (cos you just can't... Alan and IngoB can tell you why...and proably give different and equally true reasons for it)

So what they do is wait for an event at CERN that ought to produce lots of neutrinos as a by-product (and CERN being CERN those are quite common) and then estimate the times that they will have been made. At the other end they record a cluster of neutrinos a fraction of a second later.

So there is a statistical distribution of neutrino production. Millions are made in a tiny space of time - but it is over a period of time, not all at once. Of those millions a few get caught in the Gran Sasso. That gives you a statistical estimate of the likely average time of flight. Repeat a few thousand times and there you are.

So my non-physicists guess is that there is some skew in the timing of the neutrino release, and a few - a very few - are being produced slightly earlier than predicted.
 
Posted by Alan Cresswell (# 31) on :
 
There's not very much "waiting for an event" going on. The neutrinos are produced in a dedicated accelerator by collisions between protons and a graphite target. This results in pions and kaons, that decay into muons and muon-neutrinos. The pions and kaons are partially focussed to generate a neutrino beam aimed at the OPERA detector in Gran Sasso, arriving approximately 3ms later.

The neutrinos are generated in a pulse, defined primarily by the duration of the proton package (10.5 us) with the decay of the kaons and pions being decidedly second order. There are muon detectors behind the hadron stop which gives the production time of the muon pulse (and hence the neutrinos). If the neutrinos all travel at the same speed you'll get a 10.5 us burst of neutrinos at the OPERA detector; if they travel at different speeds this will spread out slightly in time. The time spread in the muon detectors will be slightly wider because of some speed difference between different energy muons. Although with less than 1km between the target and the muon detectors this effect will be very small.
 
Posted by Sioni Sais (# 5713) on :
 
Thanks Alan, I was wondering how anyone could say that the neutrinos arriving were those that had left!

Then again, I'm thinking about Feynman and Quantum Electro-Dynamics. Did he expound a hypothesis that a particle could cease to be at one point only to 'appear' elsewhere at the same time? Could that account for neutrinos moving faster than light?
 
Posted by IngoB (# 8700) on :
 
quote:
Originally posted by Boogie:
I just think it shows how wonderfully complex the universe is and just how little we know about it, even with our incredible scientific knowledge and advances. Surely this is what excites and motivates scientists to find out more?
Naw, we are mostly into science for the booze and loose women... [Biased]

I have no idea what's going on here. It is a very safe bet that some systematic (rather than statistical) error has occurred in the measurement. However, the people working on this experiment are not at all unaware that this is the safe bet, and I hence doubt that the final explanation will be particularly straightforward.

Neither am I so sure what would actually be the practical consequence of having neutrinos travel faster than light. This would require some careful re-thinking. However, merely because Special Relativity was "more true" than Newton's mechanics did not mean that horse carts suddenly moved at light speed. If there is something new to come beyond Relativity, then it will not show up in most things we observe and measure. Why? Because it has not shown up in most things we observe and measure. Nature does not change just because we gain a clue. For lots and lots of stuff, including some pretty far our stuff, Relativity "works" perfectly fine as a description. So anything new will have to reproduce all those results, as they will not suddenly vanish in a puff of smoke.

Hence this is likely an error. And if it is not, then it may be revolutionary, but it is not going to "shatter physics" in the sense many people think of this. Also I wouldn't hold my breath for warp drives...
 
Posted by Eutychus (# 3081) on :
 
They've done it again.

Or was the result back in September merely a side-effect of this one? [Paranoid]
 
Posted by ken (# 2460) on :
 
They set up another experiment to work out the answer in 2067 and they are trying to tell us what to build to get the right answer [Biased]
 
Posted by Jonah the Whale (# 1244) on :
 
My guess is that it's a few of the September neutrinos that just took their time. Reminds me of a joke:
The barkeeper says "we don't serve neutrinos in here".
A neutrino goes into a bar.
 
Posted by Marvin the Martian (# 4360) on :
 
quote:
Originally posted by Jonah the Whale:
The barkeeper says "we don't serve neutrinos in here".
A neutrino goes into a bar.
Damn you - I was going to post that one!
(and it's "we don't serve faster-than-light particles in here" [Razz] )
 
Posted by Imaginary Friend (# 186) on :
 
I still want to see verification from another laboratory before I believe it.
 
Posted by Moo (# 107) on :
 
quote:
Originally posted by Imaginary Friend:
I still want to see verification from another laboratory before I believe it.
How many other laboratories can reproduce the experiment?

Moo
 
Posted by Doc Tor (# 9748) on :
 
quote:
Originally posted by Moo:
quote:
Originally posted by Imaginary Friend:
I still want to see verification from another laboratory before I believe it.
How many other laboratories can reproduce the experiment?

Moo
A couple, at least. And there are also astronomical observations: supernova-powered neutrino bursts seem to be coming in on time, despite the hundreds of thousands of light years they've travelled. You'd think if they were FTL, the discrepancies would have shown up there first.
 
Posted by comet (# 10353) on :
 
quote:
Originally posted by IngoB:
However, merely because Special Relativity was "more true" than Newton's mechanics did not mean that horse carts suddenly moved at light speed. If there is something new to come beyond Relativity, then it will not show up in most things we observe and measure. Why? Because it has not shown up in most things we observe and measure. Nature does not change just because we gain a clue.
a very good point. I remember a few years ago hearing an announcement that scientists had disproven the Bernoulli Effect. My first thought was that thankfully the airplanes and birds all didn't know this or they would fall out of the sky. [Biased]
 
Posted by Honest Ron Bacardi (# 38) on :
 
There are supposed to be four other teams poised to check this one out - two other CERN teams, a US one and a Japanese one.

I agree that some sort of systematic error is the most likely - I think the team is on record as saying something similar. But if it turns out to be a true effect then I'm not sure it will be necessary to tear up any text books. It may be necessary to write a few new ones though.
 
Posted by redderfreak (# 15191) on :
 
quote:
Originally posted by Pooks:
I come across this: Tesla. So the thought that something could move faster than the speed of light is not new.
Nice one. To my simple engineering brain, I can't see why the visual appearance (by the arrival of light) should be any more significant than the sonic appearance (by the arrival of sound waves) to demonstrate reality. They are both sensory phenomena which are time and materially bound, indicative of but separate from reality. Why should the speed of light be sacrosanct, any more than the speed of sound?
 
Posted by Sober Preacher's Kid (# 12699) on :
 
Because of Maxwell's Equations, which I spent a course learning.

Maxwell's Equations describe the interrelation of magnetism and electricity and form the basis of electrodynamics.

[url= http://en.wikipedia.org/wiki/Maxwell%27s_equations]See wiki[/url]

If you assume you are operating in a vacuum, you can use Maxwell's Equations to extract the formulation c = 1/sqrt(M0E0)

M0 is the permeability of free space (to magnetic flux) and E0 is the permittivity to electric flux or charge. It proved that the speed of light is determined by electrical and magnetic constants which are normally unrelated to speed. It proved that light was an electromagnetic phenomenon and M0 and E0 describe fundamental properties of space that provide a "speed limit" for Electromagnetic phenomenon.

It works out too that there is a fundamental impedance or resistance of free space of 377 ohms/m

Einstein took that idea one step further and said that the speed of light is the fastest speed than can exist in an inertial frame of reference. Objects with mass can travel at speed up to c and c is the speed at which massless pheonomeon (EM waves) travel; Einstein asserted that c is a fundamental concept broader than electromagnetism and is binding on anything in an inertial frame of reference.

If the experiment at CERN is correct then Einstein's fundamental assertion about c in special and general relativity will be incorrect. It would means that neutrinos either cannot interact with EM phenomenon or if they do we will need a new fundamental law to describe the interaction.
 
Posted by Kaplan Corday (# 16119) on :
 
quote:
Originally posted by Tortuf:
Scientists at CERN have apparently measured particles traveling faster than the speed of light
I've heard that they turned out to be people trying to get out of a Benny Hinn meeting before the collection.
 
Posted by Schroedinger's cat (# 64) on :
 
The latest news - from a New Scientist tweet - indiactes that they have still not disproven this, and may have replicated it.

See here
 
Posted by Eutychus (# 3081) on :
 
This is confusing. Are you travelling slower than light?
 
Posted by fletcher christian (# 13919) on :
 
This explains why those atonement threads keep coming up again and again
 
Posted by Schroedinger's cat (# 64) on :
 
Probably. I commute in FCC. Slower than most things.....
 
Posted by Martin PC not & Ship's Biohazard (# 368) on :
 
Bloke on the bus as I am, they ent disproved nuthin. There's nuthin to disprove. They ent proved nuthin. Replication with the same set-up proves nothing. Replication by every possible site on the planet would be something. And no theodolite is going to be accurate over several hundred klicks to one cm.

As has been said, the supernova neutrinos didn't get here faster than the light.

60 nanos is 60 feet, is satnav that good ? Weapons grade ?
 
Posted by Honest Ron Bacardi (# 38) on :
 
The timing is done using two Cs137 clocks cross-correlated with a third atomic clock on board one of the GPS satellites I think. I don't know how they do the distance measurement to be honest, though GPS is hardly accurate enough for that.

Re the supernova neutrinos - (long answer coming up) - these will have passed through space, which is a vacuum to the first approximation. They do not change in such an environment. Neutrinos come in 3 quantum flavours, and when passing through dense material (such as the core of the sun), they oscillate between the three different flavours. This experiment was designed to examine this oscillation in some way, which is why they were being fired through several hundred kilometres of rock. If a neutrino changes flavour, its mass changes slightly, therefore it will move at a slightly different speed (massive simplification).

I am sure that the physicists involved are competent enough to devise an experiment whose power is adequate to discover what they are looking for. Although this business is an interesting side-effect, the same criteria of adequate accuracy in measuring distance, time etc. are going to be relevant. But I agree with you - nothing is proved or disproved so far. However, annoying inconsistencies have historically been a fruitful source of new discoveries in the past, so it's right that they are throwing this business open at the earliest opportunity for confirmation or refutation.
 
Posted by Honest Ron Bacardi (# 38) on :
 
Apologies - that should have been Cs133 clocks in the above post.
 
Posted by Martin PC not & Ship's Biohazard (# 368) on :
 
Awesome. Indeed it is 133, the only stable isotope, that's used in atomic clocks.

Nice point - taken - about the vacuum too.

Just wondering, what's the speed of light in granite ? And I'm not being facetious. Gamma rays of course. And not very far at that.
 
Posted by Johnny S (# 12581) on :
 
quote:
Originally posted by Martin PC not & Ship's Biohazard:
Bloke on the bus as I am, they ent disproved nuthin.
But have you taken into account the velocity of the bus in your calculations Martin?

(Although if it was a no. 47 I suppose it is safe to assume that it is stationary.)
 
Posted by Enoch (# 14322) on :
 
Somebody suggested this afternoon it was because nobody had realised that the Cern clock had been synchronised with the time signal on a digital radio whereas the clock in the Italian laboratory had been synchronised with the ordinary FM time signal - and nobody had thought to check. That would explain everything.
 
Posted by Doc Tor (# 9748) on :
 
AFAIK, both clocks have been synchronised with the GPS signal. However, there is an analysis which may show that the discrepancy is due to frame-shifting caused by the satellites' high relative velocities.

Lots more work to be done.
 
Posted by Alan Cresswell (# 31) on :
 
quote:
Originally posted by Honest Ron Bacardi:
I don't know how they do the distance measurement to be honest, though GPS is hardly accurate enough for that.
For relative measurements is a relatively small area (ie: where the majority of the signals come from the same satelittes) GPS can be very accurate (sub cm) if you take time and care. My guess would be Italy-Switzerland would be too far for such techniques ... but it there was an intermediate point which could be the base for relative positioning at both ends of the experiment then the estimation is simple. Of course, probably would need multiple intermediate positions, with compounding uncertainty. But, it should be well within the competance of any major topographic science unit.

quote:
Re the supernova neutrinos - (long answer coming up) - these will have passed through space, which is a vacuum to the first approximation. They do not change in such an environment. Neutrinos come in 3 quantum flavours, and when passing through dense material (such as the core of the sun), they oscillate between the three different flavours. This experiment was designed to examine this oscillation in some way, which is why they were being fired through several hundred kilometres of rock. If a neutrino changes flavour, its mass changes slightly, therefore it will move at a slightly different speed (massive simplification).
If neutrinos have mass, and if the different flavours have different masses, then they will travel at different speeds in both a vacuum and in media (probably more pronounced in media). But, those speeds will all be very very very slightly slower than light, they should not under any circumstances be faster than light. The simultaneous arrival of supernova photons and neutrinos is very good supporting evidence of the masslessness (or exceptionally small mass) of neutrinos.

The fluctuation of neutrinos between different flavours is a postulated explanation for the substantially smaller number of solar neutrinos detected than expected - the theory being that some fluctuate to other flavours to which the detectors used are insensitive. The primary purpose of this experiment is to determine if there is any fluctuation, and if so quantify it. Measurements of the speed of the neutrinos would be a bonus - by determining how much slower than light they are would give an independent estimate of their mass.
 
Posted by Eutychus (# 3081) on :
 
Would this be a good point to mention The Songs of Distant Earth and the solar neutrino problem?

Perhaps the sun is about to go nova after all.
 
Posted by Martin PC not & Ship's Biohazard (# 368) on :
 
Ah, Johnny, stationary relative to hhwot?
 
Posted by comet (# 10353) on :
 
I have nothing to contribute to this discussion at all, but it has fueled several excellent discussions with my kids over the last few days. so - thank you everyone!
 
Posted by Adeodatus (# 4992) on :
 
I've been trying to get my head round this by trying to imagine - if it's true - how much of modern science is going to have to be rewritten from scratch.

Quite a lot, as it turns out. The cosmologists in particular are going to be quite busy.
 
Posted by Sober Preacher's Kid (# 12699) on :
 
Just to be clear, Maxwell's unifying theory of Electromagnetism was the crowning achievement of 19th Century Physics. It states that c was the ultimate speed limit for EM phenomena.

Einstein took that two steps further in Special Relativity. He said that c was the fastest speed that could ever be observed in an inertial frame of reference. Anything with mass would travel slightly slower than c. If you have mass, you can't break c. Relativity kicks in.

If this experiment pans out then neutrinos, an object with mass, will have been observed to break c. This means Einstein's bold assertion of the universality of c (that it wasn't just an EM limit) was wrong. That is intensely interesting.
 
Posted by Tortuf (# 3784) on :
 
If Einstein's special theory of relativity is proven to be wrong, it might pave the way for much simpler and more elegant grand unification theories.

My approval of a theory as being elegant does not, by any means, mean that the theory is correct. On the other hand, the attempts at a GUT like the variations on the string theory look a lot more like a theory designed by a Pentagon purchasing team than a description of God's handiwork.

[Can't do simple spelling.]

[ 21. November 2011, 02:10: Message edited by: Tortuf ]
 
Posted by Jonah the Whale (# 1244) on :
 
quote:
Originally posted by Tortuf:
If Einstein's special theory of relativity is proven to be wrong, it might pave the way for much simpler and more elegant grand unification.]
Do you think so? I feel way out of my depth here, but my gut feeling is that any unification theories, if this is confirmed, would have to be even more complex than the inadequate ones we have already.
 
Posted by Doc Tor (# 9748) on :
 
quote:
Originally posted by Jonah the Whale:
quote:
Originally posted by Tortuf:
If Einstein's special theory of relativity is proven to be wrong, it might pave the way for much simpler and more elegant grand unification.]
Do you think so? I feel way out of my depth here, but my gut feeling is that any unification theories, if this is confirmed, would have to be even more complex than the inadequate ones we have already.
Maxwell's unification produced equations which, while complex to understand, were simple to describe.

It might be that a GUT requires half a rainforest's worth of paper to write out, but I'd be disappointed if it didn't fit on the front of a t-shirt.
 
Posted by LeRoc (# 3216) on :
 
In the 19th Century, scientists found out that they could unify some natural phenomena that were apparently quite different, in remarkably simple equation. An example is the unification of electricity and magnetism in Maxwell's Equations (which Doc Tor already mentioned).

In the 20th Century, when Relativity Theory and Quantum Mechanics were developed, although they can be very complex and difficult to understand, some very simple equations lie at the basis of them.

Scientists have come to appreciate the esthetics of a beautiful, simple formula that manages to unite and explain some quite different things. So in a way, they try to look for this kind of formulas. There is no intrinsic reason why a Grand Unifying Theory should be expressable as a simple formula, but in some ways, scientists have come to expect it.

The best theory about matter in the Universe we have so far is the Standard Model. It is an attempt at such a Unification Theory, but it falls short in that (mainly because it doesn't include gravity). Also, its equations are a bit messy. They aren't as simple and elegant as the other theories I mentioned before.

So, the expectation (which may be based on nothing more than wishful thinking) is that the real GUT will be a simple, elegant formula. I forgot which was the scientist who said: "The GUT will be a simple formula that you could print on a T-shirt", but I have no doubt other Shipmates will be able to help me out.


[ETA: Oops, that last bit was already said by Doc Tor as well.]

[ 21. November 2011, 07:11: Message edited by: LeRoc ]
 
Posted by Doc Tor (# 9748) on :
 
quote:
Originally posted by LeRoc:
I forgot which was the scientist who said: "The GUT will be a simple formula that you could print on a T-shirt", but I have no doubt other Shipmates will be able to help me out.


[ETA: Oops, that last bit was already said by Doc Tor as well.]
Dammit. I thought I'd just made that up! To the Bat-google...
 
Posted by Doc Tor (# 9748) on :
 
Leon Lederman:

quote:
"My ambition is to live to see all of physics reduced to a formula so elegant and simple that it will fit easily on the front of a T-shirt."

 
Posted by LeRoc (# 3216) on :
 
I bow to your superior Google-Fu. I couldn't find it.
 
Posted by Johnny S (# 12581) on :
 
quote:
Originally posted by Martin PC not & Ship's Biohazard:
Ah, Johnny, stationary relative to hhwot?
Good point.

Maybe it was stationery instead.
 
Posted by Ann (# 94) on :
 
quote:
Originally posted by Johnny S:
quote:
Originally posted by Martin PC not & Ship's Biohazard:
Ah, Johnny, stationary relative to hhwot?
Good point.

Maybe it was stationery instead.
You mean written down on a piece of paper?

(You were right the first time.)
 
Posted by IngoB (# 8700) on :
 
quote:
Originally posted by Doc Tor:
Leon Lederman:
quote:
"My ambition is to live to see all of physics reduced to a formula so elegant and simple that it will fit easily on the front of a T-shirt."
Given that he was born in 1922, it's a fair bet that his ambition will remain unfulfilled.

Also, this is just a catchy way of phrasing "mathematical / conceptual beauty" for lay people. For example, Maxwell's theory can be written as
∂_μ F^μν = 1/c J^ν
∂_μ ƒ^μν = 0
(_=subscript, ^=superscript follows till space). That will certainly fit on a t-shirt, but the background knowledge required to make sense of this most definitely will not. If nature is "mathematically / conceptually beautiful" in its fundamental laws, then invariably we will invent some clever way of writing these laws so compactly as to fit on a t-shirt. But that sort of brevity is not really the criterion of "mathematical / conceptual beauty", just a consequence.

Furthermore, the problem with the so-called Standard Model is not really that its component theories themselves are "ugly". At least not unless you've got very discerning taste in Lie algebras. The problem is that the Standard Model does not really "unify" these theories, but rather is just their amalgamation. There are some issues with the Standard Model theory that are "ugly" as it stands. However, personally I'm not convinced that physics must turn out to be "unified". Maybe there simply are several interlocking fundamental laws, not just one. I don't think that that is necessarily "uglier".
 
Posted by Higgs Bosun (# 16582) on :
 
quote:
Originally posted by Sober Preacher's Kid:
Just to be clear, Maxwell's unifying theory of Electromagnetism was the crowning achievement of 19th Century Physics. It states that c was the ultimate speed limit for EM phenomena.

Einstein took that two steps further in Special Relativity. He said that c was the fastest speed that could ever be observed in an inertial frame of reference. Anything with mass would travel slightly slower than c. If you have mass, you can't break c. Relativity kicks in.

If this experiment pans out then neutrinos, an object with mass, will have been observed to break c. This means Einstein's bold assertion of the universality of c (that it wasn't just an EM limit) was wrong. That is intensely interesting.
Maxwell derived his equations, and then pointed out that they could describe an electromagnetic wave even when there are no charges or currents to support them. That is, an EM wave in a vacuum. However, the physicists of the time thought that these EM waves had to be 'in' something, which was called the "luminiferous aether". If one moved with respect to this, then the speed would not appear to be 'c'. Michaelson and Morley's famous experiment was an attempt to detect this aether from the change in motion of the Earth. They failed. Which was much more interesting.

Lorentz then showed that Maxwell's equations were invariant under a set of transformations, which - unlike the Galilean transformation of Newtonian physics, mixes time and spacial coordinates.

Einstein took this result, and his insight was that the Lorentz transformation reflected the underlying structure of what we now call Space-Time. If we consider two events in space and time, the 'interval' between them can be what is known as 'time-like', 'space-like' or between these 'null'. The important distinction between the first two is that all observers agree on the time ordering of events separated by a time-like interval, but do not do so for events separated by a space-like interval. An interval is a separation in space and a separation in time, which can be regarded as a velocity (the former divided by the latter).

Null intervals correspond to the speed of 'c', and so velocities greater than 'c' correspond to space-like intervals. This is where the idea of time travel comes from, as if something travels faster than 'c' between A and B, some observers have A before B, and others B before A.

Special Relativity (SR) does not forbid speeds faster than 'c'. However, the time ordering ambiguity means that it is generally held that causally connected events are connected by time-like intervals, i.e. less than 'c'.

(This is for the flat Space-Time of SR, when you add in the curvature of space-time described by General Relativity, then more interesting cases can be considered, with what are known as closed time-like lines).

Adding in dynamics, SR states that to accelerate a mass from rest (relative to you) up to 'c' would take an infinite amount of energy. However, for something without mass, the slightest puff will take it up to 'c'. So, rather that 'c' being "the speed of light", light find itself travelling along a null interval - part of the structure of space-time - (and so at 'c') because it is massless.

But this does mean that neutrinos travelling apparently faster than 'c' is very interesting indeed. If there is no systematic error involved, then it does imply something interesting about the very structure of space-time.
 
Posted by Imaginary Friend (# 186) on :
 
New theoretical calculations cast doubts on 'superluminal' claims. These guys suggest that any particles traveling faster than light should emit Cerenkov radiation but that there was no sign of any energy loss in the neutrino packets used in the experiment.
 
Posted by IngoB (# 8700) on :
 
quote:
Originally posted by Imaginary Friend:
New theoretical calculations cast doubts on 'superluminal' claims. These guys suggest that any particles traveling faster than light should emit Cerenkov radiation but that there was no sign of any energy loss in the neutrino packets used in the experiment.
This experimental counter-claim is heavily based on this theoretical work. It has significance if, and only if, superluminally propagating neutrinos obey "regular" physics concerning particle decays as they speed along in a way that is at odds with "regular" physics. I hence do not think that this is a "refutation" as such, as the authors falsely claim. It's a refutation in terms of "regular" physics, perhaps. Mind you, I don't believe in the OPERA claim either. At all. But I call a "not so fast" on this one.

Usefully, this paper does point out that the supernova result is not at odds with the OPERA claim, but that it can be dealt with rather straightforwardly in terms of the very different energies of the neutrinos in question: "Thus, the alleged anomaly must be energy dependent, decreasing rapidly from 10 GeV to 10 MeV."
 
Posted by Doc Tor (# 9748) on :
 
quote:
Originally posted by IngoB:
Usefully, this paper does point out that the supernova result is not at odds with the OPERA claim, but that it can be dealt with rather straightforwardly in terms of the very different energies of the neutrinos in question: "Thus, the alleged anomaly must be energy dependent, decreasing rapidly from 10 GeV to 10 MeV."
This is starting to have the whiff that surrounded the 'fifth force' (mid-80s to early 90s, popularly anti-gravity, but not really): the range and effect of that got whittled away until it upped and evaporated completely.
 
Posted by Eutychus (# 3081) on :
 
Ah, hmm, as you were (are? will be? wioll haven been?), perhaps...

(agh, I see belatedly that I've fallen for the Schroedinger's Cat syndrome, these are the same findings that IF reported. Apologies)

[ 22. November 2011, 05:18: Message edited by: Eutychus ]
 
Posted by Alan Cresswell (# 31) on :
 
quote:
Originally posted by Imaginary Friend:
These guys suggest that any particles traveling faster than light should emit Cerenkov radiation but that there was no sign of any energy loss in the neutrino packets used in the experiment.
I'm not sure who was quoted in the Grauniad about Cerenkov radiation - it looks like it should be Jim Al-Khalili. But, there's one important word missing. Cerenkov radiation is a very well understood phenomenum, it occurs when any charged particles travel faster than light in that medium. Neutrinos are not charged particles, and so should not produce Cerenkov radiation - neutrons and photons don't either. That doesn't mean that super-luminal uncharged particles won't lose energy by other meand, but it won't be Cerenkov radiation.
 
Posted by IngoB (# 8700) on :
 
quote:
Originally posted by Alan Cresswell:
Cerenkov radiation is a very well understood phenomenum, it occurs when any charged particles travel faster than light in that medium. Neutrinos are not charged particles, and so should not produce Cerenkov radiation - neutrons and photons don't either. That doesn't mean that super-luminal uncharged particles won't lose energy by other meand, but it won't be Cerenkov radiation.
Well, by something analogous to Cerenkov radiation: ν → ν + e+ + e- as compared to say e- → e- γ. At least that's what Cohen and Glashow claim...
 
Posted by Dal Segno (# 14673) on :
 
quote:
Originally posted by IngoB:
Well, by something analogous to Cerenkov radiation: ν → ν + e+ + e- as compared to say e- → e- γ. At least that's what Cohen and Glashow claim...
Wouldn't that cause an enormous release of energy as the generated e+ comes in contact with any of the myriad e- in the vicinity, and they annihilate?
 
Posted by Alan Cresswell (# 31) on :
 
Well, not an enormous release of energy. Just ove 1MeV per annihilation (plus a bit as the positron slows to thermal energy). But, if that mechanism does occur it would make neutrinos one hell of a lot easier to detect than they are.
 
Posted by Imaginary Friend (# 186) on :
 
quote:
Originally posted by Alan Cresswell:
quote:
Originally posted by Imaginary Friend:
These guys suggest that any particles traveling faster than light should emit Cerenkov radiation but that there was no sign of any energy loss in the neutrino packets used in the experiment.
I'm not sure who was quoted in the Grauniad about Cerenkov radiation - it looks like it should be Jim Al-Khalili. But, there's one important word missing. Cerenkov radiation is a very well understood phenomenum, it occurs when any charged particles travel faster than light in that medium. Neutrinos are not charged particles, and so should not produce Cerenkov radiation - neutrons and photons don't either. That doesn't mean that super-luminal uncharged particles won't lose energy by other meand, but it won't be Cerenkov radiation.
Yeah, you're right, and I'd had that thought too. I should have said Cerenkov-like. [Hot and Hormonal]
 
Posted by ken (# 2460) on :
 
quote:
Originally posted by Alan Cresswell:
Well, not an enormous release of energy. Just ove 1MeV per annihilation (plus a bit as the positron slows to thermal energy). But, if that mechanism does occur it would make neutrinos one hell of a lot easier to detect than they are.
And probably the space between the galaxies would be glowing. I's guess that a theory of everything that was incompatible with the night sky being dark would have some big gaps in it.

(And what's this with MeV? Will it be ergs next? When can we train the stick-in-the-mud physicists to use SI units? [Snigger] )
 
Posted by Alan Cresswell (# 31) on :
 
quote:
Originally posted by ken:
(And what's this with MeV? Will it be ergs next? When can we train the stick-in-the-mud physicists to use SI units? [Snigger] )
OK, Just over 1.6x10-13J per annihilation. Better?

BTW, I just finished drafting a paper including a section on soil erosion. Geomorphologists use units of t ha-1 yr-1, I did the calculations and reported them in SI units (kg m-2 s-1) and then converted all the literature values I compared my estimates to. Somehow I anticipate the referees noticing that if I leave it as it is ...
 
Posted by Barnabas62 (# 9110) on :
 
Ah well. I've been hoping for some developments which would bring warp-speed engines back into the realm of the possible. Looks like all us SF addicts will just have to dream on ..

Mind you, I did like Tau Zero. But no doubt that is full of holes as well.
 
Posted by Gee D (# 13815) on :
 
The real answer is that the timeeeper had wound his stopwatch a bit far and it ran fast. It will get dressed up as something else (eg the neutrinos changed colour and this deceived the photo-finish machine), but that's waht really happened. Otherwise the neutrinos arrived before anyone could see them leave. Einstein would be rolling over in his grave.
 
Posted by lapsed heathen (# 4403) on :
 
You know I am not sure if I feel smarter or dumber after reading this thread. [Ultra confused]
 
Posted by M. (# 3291) on :
 
lapsed heathen, I've found it best to come to the conclusion that it's about timey-wimey stuff.

M.

[ 25. November 2011, 06:38: Message edited by: M. ]
 
Posted by LeRoc (# 3216) on :
 
Very stupid question, but when they used GPS to measure the distance between Geneva and Gran Sasso, did they take into account the curvature of the Earth? I guess this could account for 60 nanoseconds.
 
Posted by mdijon (# 8520) on :
 
Even stupid biologists plotting spatial epidemiology know about this problem so I'm sure that clever physicists do too.

Here's a link showing that the problems doing this though are not very trivial at all, and you can keep striving for greater accuracy. But these methods are for working out distance as you move around the curve... I understand that the neutrinos go straight through everything so I think if you get the co-ordinates in 3D x/y/z format it is actually straightforward.
 
Posted by LeRoc (# 3216) on :
 
quote:
mdijon: Even stupid biologists plotting spatial epidemiology know about this problem so I'm sure that clever physicists do too.
Yeah, I guess so too. I'm still surprised though: I understand the anomaly is of the order of one in a million. How can they measure the distance between these places with such accuracy using GPS? My car GPS often even places my car on the wrong road!
 
Posted by Doc Tor (# 9748) on :
 
quote:
Originally posted by LeRoc:
How can they measure the distance between these places with such accuracy using GPS? My car GPS often even places my car on the wrong road!
There are various software tweaks you can use even on civilian (downgraded) GPS signals that will fix your location to the centimetre level - and note, maps used in satnav aren't that accurate: even the 1:10000 base maps produced by the Ordnance Survey are wrong in the tens-of-metres scale.

And note, that's not the primary use of GPS here: it's for clock synchronisation.
 
Posted by Alan Cresswell (# 31) on :
 
quote:
Originally posted by mdijon:
I understand that the neutrinos go straight through everything so I think if you get the co-ordinates in 3D x/y/z format it is actually straightforward.
There is an "Earth Centred Coordinate" system, and conversion to that from the WGS84 lat/long from GPS is straight forward (I've coded that myself at one point). As has been said, cm precision is very easy to achieve with GPS - even with the receivers in your car sat-nav (if you're a) willing to leaveyour car stationary for several days to get the fix, b) if you have a second sat-nav at some known fixed point and c) you have the cables to download all the data, including the output strings that identify which satelittes used for each measurement, into a computer; c) being the hardest as many sat-navs aren't made assuming you'll want that information, even though the receiver will almost certainly generate it, and so you may need to dismantle your sat-nav and solder in some new connections).
 
Posted by LeRoc (# 3216) on :
 
And the centimeter level is accurate enough to measure this 60 nanosecond anomaly?
 
Posted by LeRoc (# 3216) on :
 
quote:
LeRoc: And the centimeter level is accurate enough to measure this 60 nanosecond anomaly?
Duh, multiply the light speed by a nanosecond. I could have calculated that myself.
 
Posted by Alan Cresswell (# 31) on :
 
Given the budget for the experiment, I'm sure there would have been enough for the relatively small cost of buying better GPS systems than the standard car sat-nav, or hiring a survey organisation with such equipment. That would give better than cm precision from the GPS. Of course, you'd still need to accurately survey all the underground passages and tunnels to get a precise measurement of the relative locations of the neutrino source at CERN and the detector in Italy.
 
Posted by LeRoc (# 3216) on :
 
Alright, I've done my calculations now. The 60 nanosecond anomaly translates to a 18m/60ft distance, isn't it? I'm convinced now that distance measures aren't the problem here. Even I could pinpoint myself with that kind of accuracy.
 
Posted by egg (# 3982) on :
 
My granddaughter tells me the answer:

"A simple error - the satellites move at such speeds that relativistic effects must be taken into account. This changes the measurements of time, so that the neutrinos actually travelled less distance than the scientists thought they had. The correction is slight, but when calculated, the neutrinos do not travel faster than the speed of light.

Physics is not so easily caught out [Smile] "

See the explanation of the original error at http://www.technologyreview.com/blog/arxiv/27260/
 
Posted by Alan Cresswell (# 31) on :
 
And, the latest news identifies two other potential sources of systematic error. Though, it's not clear if a) either of them actually affects the answer or b) even if they do whether the correction will result in sublight speed neutrinos, or even if the faster than light neutrinos go even faster.
 


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