neutrinos travel at a velocity 20 parts per million above the speed of light

[dlew22]

Re: neutrinos travel at a velocity 20 parts per million above the speed of light

The Speed of Gravity What the Experiments Say

http://metaresearch.org/cosmology/speed_of_gravity.asp


This site and paper was why I was originally interested in the cern article.

[ASH]

Re: neutrinos travel at a velocity 20 parts per million above the speed of light

Maybe You forgot the fact that Relativity is a THEORY

That is like saying that Newton's laws are theories. Until you have directly observed everything in the entire universe, for all time, and observed that it all obeys a particular "law" in exact detail, any such law is technically a "theory". But for practical purposes, relativity has been tested up the yin-yang. If it's going to break down, it is more likely to break down like Newton's laws -- by being found to be an approximation that doesn't hold under detailed scrutiny at a time or distance scale that wasn't previously testable.

[sunskyfan]

Re: neutrinos travel at a velocity 20 parts per million above the speed of light

I have never understood why people see the word "theory" and think that it challenges the credibility of something. It is a Greek word whose root, ironically, is "theo" or god. Considering the exotic (away from everyday observations) predictions that Relativity has made and that have been observed to be true we all can have high confidence it is a good explanation of the part of existence it is used to describe. If, for instance, this observation of something traveling faster than the speed of light in a vacuum were true any new "theory" would have to be 99.99% consistent with Relativity.

[ASH]

Re: neutrinos travel at a velocity 20 parts per million above the speed of light

This site and paper was why I was originally interested in the cern article.

It's interesting -- too interesting to take in by skimming. Thanks for posting the link. I'll have to read it with care when I get a chance.

[*T*]

Re: neutrinos travel at a velocity 20 parts per million above the speed of light

ASH, for your unparalleled everyday language (and correct afaikt) explanation of a master's level physics course, and in particular your wonderful description of Minkowski 4-space by means of the map analogy, I hereby nominate you for the title of iTulip's Physicist-in-Residence.
Yo' sir, are man enough for me.

T

[jtabeb]

Re: neutrinos travel at a velocity 20 parts per million above the speed of light

I think that the consternation expressed by the two of you can be attributed to a lack of precision. The paper posted by dlew22 offers an alternative model to the SR explanation of natural phenomena and employs LR, particle based gravity, a propagation speed of gravity in excess of c, and flat space-time in it's formulation. GR is not attacked in the paper referenced above (the one ASH thought would be interesting to read).

So, sgominator, is your point of contention with SR, GR (or both?)

ASH, would love to read what you think of the article when you've given it a complete read-through. (there are several more on metaresearch.org r.e. gravity). Would love to hear your take on these as well if you get the chance to read them.

[ASH]

Re: neutrinos travel at a velocity 20 parts per million above the speed of light

ASH, for your unparalleled everyday language (and correct afaikt) explanation of a master's level physics course, and in particular your wonderful description of Minkowski 4-space by means of the map analogy, I hereby nominate you for the title of iTulip's Physicist-in-Residence.
Yo' sir, are man enough for me.

T

Aw shucks, *T*. Thanks, although I think I'm acting more as a writer than a physicist, in this instance. Although I could plausibly call myself a "semiconductor device physicist", I'm really just an occasional "user of physics", which is to say I'm just another damn dirty engineer.

By the way, the 4-space/map analogy isn't mine. It is from Taylor & Wheeler -- the introductory textbook on special relativity that was used in my freshman E&M class. It's always impressive to me when a professional theoretical physicist like the celebrated John Wheeler is able to explain physics in an intuitive way, and that was one of the more "user-friendly" books I encountered at Caltech.

[jk]

Re: neutrinos travel at a velocity 20 parts per million above the speed of light

i thought that antiparticles could be viewed as particles traveling backward in time in feynman diagrams. is that right? and, if so, does it have any physical meaning?

[ASH]

Re: neutrinos travel at a velocity 20 parts per million above the speed of light

i thought that antiparticles could be viewed as particles traveling backward in time in feynman diagrams. is that right? and, if so, does it have any physical meaning?

That's correct.

This area of theory is further removed from the physics I've studied in detail, so I'm afraid I can't offer too much insight. I've dealt with symmetry operations including parity before, but I haven't ever studied the relativistic tie-in. So this is more of a book report than me speaking from deep knowledge:

As far as the direction of time goes, there's a big picture and a little picture. The big picture is that on average, entropy increases. As long as you are looking at a sequence of events that pertain to a system that is big enough for "order" and "disorder" to have meaning, you can recognize which direction time is supposed to flow, because that is the direction of increasing disorder. So even though anti-particles can be viewed as particles traveling backward in time, it is not the case that time appears to run backwards when you're dealing with antiparticles. There isn't any big picture ambiguity about the direction of time, even though you can treat individual particles as traveling forward or backward in time.

The little picture is that order and disorder are really properties of collections of particles and processes that play out over multiple interactions, so the direction of time isn't as obvious at the scale of individual particles or interactions. Here the story is that things play out the same if you flip the sign of the electric charge of the particles involved, reverse the flow of time, and look at the resulting action in a mirror. This is called "charge, parity, and time symmetry" or CPT symmetry. I read that CPT symmetry is a requirement for Lorentz symmetry to hold; Lorentz symmetry is the proposition that the laws of physics don't depend upon the orientation in space or the direction of travel of the inertial reference frame in which an experiment is performed. Lorentz symmetry and the transformations used to "translate" results from one inertial reference frame to another are normally taught as part of special relativity. Anyway, CPT symmetry says that if you flip one of these attributes, you have to flip the others as well, or else there'll be a way to differentiate between inertial reference frames. Anti-particles carry the opposite charge and have the opposite parity of their matter counterparts, so when you flip the direction of time and have to flip charge and parity as well (in order to satisfy CPT symmetry), you end up with an anti-particle. This is why a particle traveling backward in time can be viewed as equivalent to an anti-particle.

There is one interesting physical consequence. Earlier, I mentioned that virtual particle pairs can be thought of as a matter particle traveling forward in time for as long as the ambiguity about the energy present permits, before looping backward in time to its point of origin and disappearing. This round trip looks like a matter-antimatter pair being created at one time and then disappearing at another. Because of the inverse relationship between the ambiguity of time and energy, more massive virtual particles have shorter leashes: a massive particle can't get very far from its point of origin before having to return to its origin. Now, in QFT, interactions between different particles are mediated by the exchange of virtual particles called "field bosons". Massless virtual photons mediate electromagnetic interactions, and very heavy particles called W and Z bosons carry the weak nuclear force. The weak nuclear force is really only active over the distance scale of an atomic nucleus owing to the high mass of its force carrier particles, whereas the range of the electromagnetic force is infinite due to the zero rest mass of the photon. So there is an interesting connection here to the range of a fundamental force, the mass of its force carrier particle, and the fact that a matter-antimatter pair of virtual particles is equivalent to a matter particle making a round trip through time.

[yernamehear]

Re: neutrinos travel at a velocity 20 parts per million above the speed of light

Thanks Mr. Ash. I did my graduate work in Raman Spectroscopy, and we had to learn about some of these concepts, but you obviously have done more than I had to!

As you touch on, the "big" vs. "little" always comes into play. I am wondering if their ability to really measure the speed of light is as good as they think it is. (20 parts per million- I believe is what they said).

I recall that some workers were able to make something be detected at faster than the speed of light in some kind of specialized experiment. However, not all of the "information" in the photons was collected at faster than the speed of light, e.g. spin and some other parameters needed to completely describe the particles. The complete particle/set of particles was only detected at or below the speed of light. (Has to do with all the wave packets too- different way of describing the particles- as waves- the wave velocity, phase velocity, and some other velocities, which I can't recall right now.)

A lot depends on the "description" of the experiment, as you said. I look at a lot of the theoretical/models as just that: descriptions that help understand the experimental observation. The "observable" (useful!?) experiment is what really counts.

Thanks again.

That's correct.

This area of theory is further removed from the physics I've studied in detail, so I'm afraid I can't offer too much insight. I've dealt with symmetry operations including parity before, but I haven't ever studied the relativistic tie-in. So this is more of a book report than me speaking from deep knowledge:

As far as the direction of time goes, there's a big picture and a little picture. The big picture is that on average, entropy increases. As long as you are looking at a sequence of events that pertain to a system that is big enough for "order" and "disorder" to have meaning, you can recognize which direction time is supposed to flow, because that is the direction of increasing disorder.

The little picture is that order and disorder are really properties of collections of particles and processes that play out over multiple interactions, so the direction of time isn't as obvious at the scale of individual particles or interactions. Here the story is that things play out the same if you flip the sign of the electric charge of the particles involved, reverse the flow of time, and look at the resulting action in a mirror. This is called "charge, parity, and time symmetry" or CPT symmetry. I read that CPT symmetry is a requirement for Lorentz symmetry to hold; Lorentz symmetry is the proposition that the laws of physics don't depend upon the orientation in space or the direction of travel of the inertial reference frame in which an experiment is performed. Lorentz symmetry and the transformations used to "translate" results from one inertial reference frame to another are normally taught as part of special relativity. Anyway, CPT symmetry says that if you flip one of these attributes, you have to flip the others as well, or else there'll be a way to differentiate between inertial reference frames. Anti-particles carry the opposite charge and have the opposite parity of their matter counterparts, so when you flip the direction of time and have to flip charge and parity as well (in order to satisfy CPT symmetry), you end up with an anti-particle. This is why a particle traveling backward in time can be viewed as equivalent to an anti-particle.

There is one interesting physical consequence. Earlier, I mentioned that virtual particle pairs can be thought of as a matter particle traveling forward in time for as long as the ambiguity about the energy present permits, before looping backward in time to its point of origin and disappearing. This round trip looks like a matter-antimatter pair being created at one time and then disappearing at another. Because of the inverse relationship between the ambiguity of time and energy, more massive virtual particles have shorter leashes: a massive particle can't get very far from its point of origin before having to return to its origin. Now, in QFT, interactions between different particles are mediated by the exchange of virtual particles called "field bosons". Massless virtual photons mediate electromagnetic interactions, and very heavy particles called W and Z bosons carry the weak nuclear force. The weak nuclear force is really only active over the distance scale of an atomic nucleus owing to the high mass of its force carrier particles, whereas the range of the electromagnetic force is infinite due to the zero rest mass of the photon. So there is an interesting connection here to the range of a fundamental force, the mass of its force carrier particle, and the fact that a matter-antimatter pair of virtual particles is equivalent to a matter particle making a round trip through time.

[ASH]

Re: neutrinos travel at a velocity 20 parts per million above the speed of light

The paper posted by dlew22 offers an alternative model to the SR explanation of natural phenomena and employs LR, particle based gravity, a propagation speed of gravity in excess of c, and flat space-time in its formulation. ...
ASH, would love to read what you think of the article when you've given it a complete read-through. (there are several more on metaresearch.org r.e. gravity). Would love to hear your take on these as well if you get the chance to read them.

I finally had a chance to read through that paper a bit more carefully, and honestly, I'm not qualified to critique the paper because one would need to be technically conversant with general relativity to spot the problems. However, based upon what I was able to turn up from reputable sources, it sounds like this is a case of a little knowledge being dangerous. The fellow isn't a raving loony, and a lot of the paper is technically accurate, but he may not understand the mainstream theory with enough depth to effectively critique and supplant it. I felt that he went off the reservation when he switched from factual statements (i.e. no aberration for gravity) to identifying problems with conventional theory and suggesting alternative interpretations. One warning sign was that for a paper in Physics Letters, the article was rather long on analogy and history, and rather short on math. In a few instances, he seemed to be arguing against what a layman's analogy for relativity says, rather than what general relativity says. That might be a sign that he's someone like me who has a background in physics, but is not professionally conversant with the most mathematically challenging branches of theoretical physics. Only I generally don't presume to overturn mainstream physics. Anyway, further to the point that he may not understand the mainstream theory well enough to identify problems with it, there's this from the abstract of the paper I linked:

In a recent paper in Physics Letters A [1], Van Flandern has argued that observations show that gravity propagates at a speed much greater than c. In the absence of direct measurements of propagation speed, Ref. [1] relies instead on directional information, in the form of observations of (the absence of) gravitational aberration. But the translation from a direction to a speed requires theoretical assumptions, and the implicit assumptions of Ref. [1]—in particular, that the interaction is purely central, with no velocity-dependent terms—do not hold for general relativity, or, for that matter, for Maxwell’s electrodynamics.

In this paper, I explicitly compute the gravitational effect of an arbitrarily accelerating source, Kinnersley’s “photon rocket” [2]. Although gravity propagates at the speed of light in general relativity, the expected aberration is almost exactly canceled by velocity-dependent terms in the interaction. While at first this cancellation seems to be “miraculous,” it can be explained from first principles by turning Van Flandern’s argument on its head: conservation of energy and angular momentum, together with the quadrupole nature of gravitational radiation, require that any causal theory have such a cancellation.

Anyway, my impression is that the problems he identifies with mainstream theory may simply represent gaps in his knowledge. But I have to rely upon what a physics professor says, because this is outside my background.

[ASH]

Re: neutrinos travel at a velocity 20 parts per million above the speed of light

As you touch on, the "big" vs. "little" always comes into play. I am wondering if their ability to really measure the speed of light is as good as they think it is. (20 parts per million- I believe is what they said).

Well, they did characterize the error of their measurement. The standard deviation was 10 ns, and their measurement was a 60 ns lag, so if they did everything right, it probably isn't noise. Then again, timing the arrival of neutrinos from SN1987A was much more accurate, and no evidence of faster propagation was found. So either something new and wonderful is happening as the neutrinos travel through the earth's crust that doesn't happen across hundreds of thousands of light-years of vacuum, or there's a systematic 60-ns delay somewhere in their timing electronics.

Another factor is that workers at Fermilab thought they saw something similar in 2007, but they dismissed it as experimental error. At least there's enough interest now that the experiment will be repeated and double-checked.

You certainly can't rule out the possibility that something weird is going on because of the recent proliferation of stuff we can't explain with current physics. Where are the super-symmetric particles I was promised? Where the hell is my dark matter? And what on earth is dark energy?

Chances are we're going to find something new and exciting pretty soon, because there's lots of stuff that doesn't fit within what we can describe with known physics. I don't necessarily think that we're going to end up supplanting the basic ground rules of relativity or quantum mechanics, but there surely must be some interesting elaborations to be discovered.


-- Cheers

[c1ue]

Re: neutrinos travel at a velocity 20 parts per million above the speed of light

You certainly can't rule out the possibility that something weird is going on because of the recent proliferation of stuff we can't explain with current physics. Where are the super-symmetric particles I was promised? Where the hell is my dark matter? And what on earth is dark energy?

As has been noted elsewhere, there do not seem to have been any fundamental breakthroughs since cutting edge physics started getting weird with string theory.

As far as I can recall, it is going on 20 years now since a major breakthrough has occurred which is physically verifiable.

Makes me wonder if all that theorizing has gone over the edge into navel gazing...

Chances are we're going to find something new and exciting pretty soon, because there's lots of stuff that doesn't fit within what we can describe with known physics. I don't necessarily think that we're going to end up supplanting the basic ground rules of relativity or quantum mechanics, but there surely must be some interesting elaborations to be discovered.

I'd hope so, otherwise we're all in a Peak Energy black hole.

[WDCRob]

Re: neutrinos travel at a velocity 20 parts per million above the speed of light

Hopefully not to hijack the thread, but this seemed a better home than starting a new one...

ASH, do you have a take on Garrett Lisi and his E8 Theory of Everything? Crackpot? Genius in the making? Wrong, but usefully so? Etc etc etc. Can't get a handle what the serious physics folks think of him, but when he first presented his paper it seemed like he had at least got their attention.

[c1ue]

Re: neutrinos travel at a velocity 20 parts per million above the speed of light

ASH, do you have a take on Garrett Lisi and his E8 Theory of Everything? Crackpot? Genius in the making? Wrong, but usefully so? Etc etc etc. Can't get a handle what the serious physics folks think of him, but when he first presented his paper it seemed like he had at least got their attention.

If you don't have a problem going to a 'denier' site, Lisi has long ago been smacked down.

http://motls.blogspot.com/2007/11/ex...theory-of.html