Dr. Michio Kaku: "The Noose Around Relativity is Tightening"

[LongTomH]

OK, don't take my word for anything; this is from Dr. Michio Kaku at Bigthink.com:

A couple of months ago, physicists at CERN, Switzerland, claimed they had found a fatal flaw in Einstein's theory of relativity. Their findings immediately lit up the Internet with activity, created widespread worldwide debate and shook the foundations of physics. These physicists were essentially putting a noose around the neck of relativity. After some criticism, they refined their experiments this week, made more precise measurements, and still confirmed their original findings.

Originally, they found that 15,000 neutrinos outraced a beam of light, reaching the finish line 60 feet ahead of a light beam, over a distance of about 450 miles. My blog entry on November 1st, "Update on the 15,000 Neutrinos That Seemed to Outrace a Beam of Light" explained more about the original experiment and how the physicists calculated the original result.

One criticism lodged against this experiment was that the beam of neutrinos was not precise, spread out over 10,000 billions of a second. Now, they have done the experiment again, with a beam spread out over 3 billionths of a second and they still find the neutrino beam outracing the light beam. If you aren't aware already -- This is extremely bad news for relativity. According to Einstein, nothing can go faster than light, so a neutrino beam cannot possibly outrace a light beam! If this is the case - All hell breaks loose, time goes backwards and all of modern physics has to essentially be redone.

But there is still hope for true believers (like me). The weak link in all this is not the neutrino beam at all, but the GPS system used to measure the distance between Geneva and Italy. Several physicists have gone public to challenge the results and claim that the CERN group in fact miscalibrated the distance between Geneva, the GPS satellite, and Italy. Since the discrepancy is on the order of 20 parts per million, it means that even tiny errors have to be factored in.

Many physicists point out that in 1987, neutrino’s and light from an ancient supernova outside our galaxy, traveling tens of thousands of light years, reached the earth at roughly the same time. So a measurement made over astronomical distances is probably more reliable than a measurement made over 450 miles. So, relativity is down, but not out. Most physicists, I think, are still rooting for Einstein.

Fair makes your head spin, doesn't it!

[WillParkinson]

1. I'm not rooting for Einstein...

And I don't believe Einstein would be rooting for himself. I believe he'd be rooting for the truth, regardless of what it turns out to be.

[Wilms]

2. You've got that right. In fact...

Einstein himself at various times had expressed doubts about the edifice of modern physics that he had helped to create— witness the remarks that follow. Perhaps his most serious expression of doubt came in a 1954 letter, the year before he died, to his friend Michel Besso: "I consider it quite possible that physics cannot be based on the field concept, i.e. on continuous structures. In that case, nothing remains of my entire castle in the air, gravitation theory included, and of the rest of modern physics."13 Biographer Abraham Pais hastens to excuse this slip from contemporary certainty about relativity theory, claiming that virtually all physicists think that this self-assessment at the end of Einstein's life was "unreasonably harsh." But just a few years earlier (1948), in an introduction to a popularized book about relativity, Einstein was also circumspect about physics, in a more general sense: ". . .the growth of our factual knowledge, together with the striving for a unified theoretical conception comprising all empirical data, has led to the present situation which is characterized— notwithstanding all successes— by an uncertainty concerning the choice of basic theoretical concepts."14

In my estimation, Einstein was a person much more cautious about dogmatic expression than those who have claimed invincibility for his relativity theories. In a letter to J. Lee in 1945, Einstein wrote: "A scientific person will never understand why he should believe opinions only because they are written in a certain book. Furthermore, he will never believe that the results of his own attempts are final."15

http://www.infinite-energy.com/iemagazine/issue38/einstein.html

[unblock]

3. but why did einstein choose light for his theory?

my (very) lay understanding is that his theory was based on the notion that nothing could travel faster than information, and information couldn't travel faster than light, as far as we knew. to the extent that neutrinos can convey information slightly faster than light, his basic theory would hold, except that the magic formula would be e=mn^2: energy = mass times the speed of neutrinos squared. sounds like this is a very tiny difference.

this, of course, assumes that the experimental result is accurate, which remains in doubt.

[laconicsax]

5. Neutrinos aren't likely superluminal.

While I don't recall the details at the moment, the speed of light in a vacuum wasn't chosen as a benchmark arbitrarily, and relativity has been confirmed countless times in the last century.

[BadgerKid]

8. I wonder if the permittivity of free space accounts for vacuum quantum fluctuations.

The idea of permittivity dates back to Coulomb's law days, which far pre-dated quantum theory.

[caraher]

9. Einstein wasn't thinking in terms of information

Prior to Einstein, the equations one usually learns when working with special relativity - mainly the Lorentz transoformations - were already known. There were many conjectures regarding length contraction, fewer regarding time dilation, and no good theoretical umbrella to put everything under. Earlier, Maxwell developed a highly successful theory of electricity and magnetism, that indeed predicted the existence of electromagnetic waves that travel at the speed of light.

What Einstein did was put a bunch of pieces together through a fresh way of looking at these puzzle pieces. On the basis of declaring that all inertial references frames are equally valid and taking the speed of light (in vacuum) to be constant in all of them, Einstein could make sense of a variety of seemingly-disparate theoretical puzzles and experimental results.

The tie-in with "information" is somewhat indirect, and has to do with how Einstein revolutionized how we look at time. The basic principle is that, using Lorentz transformations, we can always relate the time between a pair of events as measured in one reference frame to the time between the same two events as measured in any other frame. These measurements do not agree in general; however, there is a well-defined time-ordering of events in certain circumstances.

Basically, two events in spacetime separated such that something moving slower than the speed of light could be present at both have the same temporal order in every inertial reference frame. On the other hand, events that are spatially separated such that something would need to move faster than lightspeed in order to be present at both have an ambiguous temporal order - in some reference frames, A occurs before B, while in other reference frames, B occurs before A.

Because the usual notion of causality is that causes must always precede effects, there's a big problem if events A and B could have causal influences on one another - we'd have the embarrassing circumstance of future events causing past events (at least as seen in some reference frames). The language of information is perhaps a more modern way of talking about this - we can equate causal influence with a transfer of information. In any case, Einstein basically stipulates that one cannot allow causal influences - i.e. information - to travel faster than the speed of light because he wants to preserve the usual notions of causality.

This is why, in many previous reports of superluminal phenomena, one frequently finds statements to the effect that although something can be said to travel faster than the speed of light, a more careful analysis shows that no *information* travels superluminally. That's because the most important thing the "speed limit" accomplishes is to ensure that causal relationships cannot be formed between events whose time ordering is ambiguous. So long as you can't use it to send a signal, you don't upset the causal applecart! This helps make the nonlocality of quantum mechanics less threatening to relativity - while on most accounts of "wavefunction collapse" you have a "spooky action at a distance," this phenomenon cannot be used to send a signal faster than the speed of light - and thus does not threaten the causal order.

In the end, I don't think it's as simple as replacing the "speed of light" with some very similar value for "the speed of neutrinos" because relativity's foundation is not really the notion one starts with the speed of the fastest phenomenon that can carry a signal and scale everything else to it. In relativity, time measurements are about things like synchronizing clocks in motion relative to one another, and to get that right, as a matter of oft-repeated experimental fact, you need to use the speed of light to get the correct numbers - and not the speed of light plus the tiny extra bit reported for the neutrino speeds OPERA reported. It's a small difference, but large enough that numerous precision measurements over the past few decades would have noticed a discrepancy.

Thanks for the post - it got me to think more carefully about "what is special about light?" in relativity. There's more to it that what I wrote, but I think in the end it really does come down to experiment (even though there are also powerful purely theory-driven reasons to give light a privileged role).

[phantom power]

12. The reason it all started with light...

was that the electromagnetic equations governing light implied that if the apparent speed of light *could* change for different observers, it would mean that the values of certain fundamental constants must differ with your velocity:

http://en.wikipedia.org/wiki/Maxwell%27s_equations#Relation_between_electricity.2C_magnetism.2C_and_the_speed_of_light

What Einstein did was reason: fundamental constants should *not* change with velocity. If we adhere to this assumption, then the speed of light must not change with velocity: all observers must perceive the speed of light as the same constant value. At this point, something must give, and Einstein showed that what gives is perception of time :-)

Both special relativity and general relativity began with assumptions about what "ought" to be invariant with respect to velocity (and in the case of general relativity, acceleration) -and from there working out the implications. Both were beautiful examples of deriving a theory, with falsifiable predictions, that so far have held up under the best observations modern science has throw at them. So far, anyway!

[laconicsax]

4. Relativity is tested daily.

It'll take more than the anomalous neutrino result to take out relativity.

[unblock]

6. not close enough to the details, but i presume this was a finer distinction

than could have been detected previously...?

we're talking about a tiny difference between neutrino speed and light speed. i have no idea if it's within the margin of error of previous experiments.


though i agree, it's far more likely that the experiment is in error somehow.

i'd like to see a different team confirm this before getting excited.

[laconicsax]

7. Not as far as I know.

There are a lot of different ways in which relativity can be, and has been tested. It's one of, if not the most thoroughly tested theory in science.

[caraher]

10. Definitely not - the difference would have been detected easily

OPERA reports an neutrino speed of c * (1 + 2.5 x 10^-5), an excess of (3 x 10^8 m/s * 2.5 x10^-5) = 7.5 x 10^3 m/s = 7.5 km/s. According to http://njsas.org/projects/speed_of_light/index.html">one history of speed of light measurements I found, Michelson reported the speed of light to a precision better than this in 1926, and laser techniques have been over 1000 times more precise than this discrepancy.

[Chichiri]

11. My understanding is that FTL particles are consistent with Relativity . . .

. . . provided that they're traveling backward through time.

[hue]

13. CERN put an end to those erroneous findings...

Neutrinos cannot travel faster than the speed of light. There is no threat to relativity in this regard!

http://www.bbc.co.uk/news/science-environment-15830844

"Subatomic particles called neutrinos cannot move faster than the speed of light, according to a new report.

The findings challenge a result reported in September that, if true, would undermine a century of physics.

The team at the INFN-Gran Sasso laboratory in Italy said they had measured faster-than-light speeds in neutrinos sent from Cern, 730km away.

Now a different team at the same lab reports findings that, they say, cast doubt on that surprising result."

[muriel_volestrangler]

14. That's not 'an end to those erroneous findings'

It's an objection that, with one theoretical interpretation of how faster-than-light particles would behave, they would have seen different results. But the conventional theory is already contradicted by the apparent results; it's just one more aspect than any new theory would need to explain.