Re: Time for a photon.

David,

Well, I do appreciate your responses, even if it sometimes LOOKS to me like you are not reading what I say. For example, how many times do I have to say that I do NOT believe -- and I have said this in these posts from the beginning -- that time stops for massless particles? One of my first points was that we should not ASSume, simply because neutrinos transform, that they cannot be massless particles. Okay? I'm sure we can disagree on enough things without "disagreeing" on things we actually agree on! Again, because I want to discuss things I don't understand or don't agree on, rather than something I do understand and do agree with you on, I do think that a particle with rest mass moving at c (impossible, but for the sake of argument) will have a time-rate of zero, but I do not think that this means that particles with zero rest-mass, even though they also move at c, have a time-rate of zero. So, hopefully, that point of false disagreement will end.

Let's get to the interesting stuff! First, does the ability of neutrinos to transform mean that they have mass? Google nova neutrino rest mass

http://science.slashdot.org/article.pl?sid=06/04/01/227223&from=rss

States that:

"BBC News reports that results from the MINOS experiment have confirmed that neutrinos have mass. To look for neutrino oscillations, scientists created muon neutrinos in a particle accelerator at the Fermi National Accelerator Laboratory (Fermilab). After passing through a particle detector at Fermilab, a high intensity beam of neutrinos travelled to another particle detector 724km (450 miles) away in a disused mine in Soudan, US. The set up established that fewer particles were being detected at the Soudan site than had been sent from Fermilab, which confirmed that some neutrinos changed their flavor on the way - an effect called neutrino flavor oscillation, which requires them to have mass."

And from the following, much the same thing

http://www.fnal.gov/pub/presspass/press_releases/minos_3-30-06.html

Now, although they state categorically that neutrinos MUST have mass because "neutrino oscillation" (the correct term, not my "neutrino transform") would otherwise not be possible, but I have not yet found their reasoning as to why. On NOVA, I am certain they said that it was because particles moving at c could not oscillate because time stands still for any particle moving at c, but it is possible that on this one point, they were, or I am, confused. Then again, maybe not. But just because I pointed out that what applies to particles WITH rest mass does not necessarily apply to particles WITHOUT rest mass, and you agreed, does not mean that anyone else has thought of this. One's initial reaction is to assume that everyone has thought of this, but if you are any student of the history of science, then you know better. For one thing -- and this is a very suspicious indication, not a proof -- why else would they think that the ability to oscillate means that neutrinos MUST have rest mass? Also, it really would be ridiculously easy to make a shift-error, specifically, to take the fact that time does stand still for particles with mass moving at c, and then conclude that, therefore, time must stand still for massless particles, since they move at c, forgetting that the SHIFT from particles with mass to massless particles means that, as a point of valid logical reasoning, conclusions which apply to the former cannot be ASSumed to apply to the latter.

At the second website they said:

"If neutrinos had no mass, the particles would not change as they traverse the Earth and the MINOS detector in Soudan would have recorded 177 +/- 11 muon neutrinos. Instead, the MINOS collaboration found only 92 muon neutrino events--a clear observation of muon neutrino disappearance and hence neutrino mass. The deficit as a function of energy is consistent with the hypothesis of neutrino oscilations and yields a value of delta m2, the square of the mass difference between two different types of neutrinos, equal to 0.0031 eV2 +/- 0.0006 eV2 (statistical uncertainty) +/- 0.0001 eV2 (systematic uncertainty)."

Here I'm a bit confused, perhaps you can help. The term "eV2" is unfamiliar to me. It appears to mean "the square of the mass difference between two different types of neutrinos," their words, obviously, which I THINK means that the difference in mass is sqrt(0.0031 eV2) = 0.056 eV? Plus or minus the error, of course.

Okay, some trimming:

[snip]

Let me ask you... does it matter? Current theory requires the neutrino to have mass. Current observation is that it has mass.

Actually, I believe that no one has "measured" the rest mass of a neutrino. They have deduced from various observations that it must have rest mass, and that the rest mass must be (1) below a certain number, as the result of certain experiments, and (2) that there is a difference in rest mass between two types, per the article above. In other words, it is current deduction, not direct observation, that indicates rest mass. A subtle, but significant, distinction, since the latter rests on assumptions that may be either false or not sufficiently inclusive.

I don't understand what this has to do with neutrinos
changing, or the implications, if any, for the question
of whether they have rest mass.


I was attempting to locate massless particles with any observed/predicted halflives. You seem to feel that massless particles do not experience time.

See paragraph one on my repeatedly stated opinion that we CANNOT assume that "massless particles do not experience time."

[snip]


No quantum object ever ages. Only a population
of such objects do. So what quantum objects
must do is "change" in some way, and the
population accumulates this into "aging". I
welcome any/all more correct interpretations.

Yes, yes, that's why I put "aging" in quotes, so
that it would hopefully be clear that I was referring
to internal changes in the object, rather than some
deterioration.


Is "momentum" internal to the object? Is "polarization" internal to the object?

I would say no, meaning that the fact that these can be changed tells us nothing about the time-rate of the object in question, but I suspect this all relates to what appears to be your mistaken belief -- perhaps my fault for writing badly -- that I think "massless particles do not experience time."


I know of no theory that ACTUALLY predicts this,
but it seems to be a commonly held ASSumption
that, of course, this is one of relativity's predictions.

Relativity says nothing about time rate for a photon,
only time rate for "frames" inhabited by massive
particles.

That's what I thought, too, hence the puzzlement on
the show's comments, which I still suspect most
physicists actually believe (that would be a pretty
serious blunder for NOVA to make; possible, but
doubtful).


*Always* doubt. In the limit, Lorentz transforms
indicate that time should not pass for any particle
travelling at c. But in the same limit, no finite result
can be obtained for particle energy, whether that
particle be in the "c-frame" or in the rest of the
Universe. Yet photons always yield a finite result... like any object travelling less than c.

I'm not sure I see your point. The LT definitely refers
to objects with rest mass, but not, as far as I know,
to objects without rest mass (to conclude that
since the time-rate of rest mass objects drops to
zero, THEREFORE anything moving at c must have
a time-rate of zero, is another example of what I
mean by "shift-error").


Forgive me, but I thought you said:

I know of no theory that ACTUALLY predicts this,
but it seems to be a commonly held ASSumption
that, of course, this is one of relativity's predictions.

... it appears that whoever said that is expecting all who have made this "ASSumption" to have made your acknowledged "shift-error"...

Um, maybe? It would UNQUESTIONABLY be a shift error to ASSUME that what applies to particles with rest mass, AUTOMATICALLY applies to massless particles, but that doesn't mean that they could not, coincidently, have the same properties. It simply means we cannot, logically, assume that. I'm not sure, however, if this answers your point, since I'm not certain what your point is.

[snip]


Come on, cut the crap.


It was an attempt at a mild joke. I am sorry that you cannot see such, or feel on the defensive. This was not my intent.

Sounds good, we'll move on.


If it was a widely held
belief among physicists that "neutrino
transformation" did NOT at least indicate rest
mass, the odds of NOVA claiming otherwise
would be extremely low.


Why do you say this? First of all, you have to be 100% sure that what you remember *now* is what they said... in full context. Then you have to allow them some poetic license. As I have said, and linked to, theory already predicted that neutrinos had mass. (Equally true is that there are other theories that say nothing at all about neutrino mass, and still others that expect(ed) it/them to be massless.)

I think it is a valid statistical analysis on my part. I did not say, "there is no possibility that NOVA did not say that "transform (oscillation) = rest mass, SINCE the time-rate of massless particles is zero," I said that the odds of this were extremely low, and it seems obvious to me that a widely known fact would not be categorically contradicted by NOVA, although it is indeed possible, for the reasons you state. As it turns out, NOVA DID SAY that oscillation = rest mass, and the only remaining question for us is whether they believe that massless particles cannot oscillate because their time-rate is zero, just as it would be for particles with rest mass moving at c. Perhaps it is some other property of massless particles that would prevent them from oscillating. Can you come up with even one wild guess, other than what I said that NOVA said (massless = c = zero time-rate), that could explain why massless particles cannot oscillate?

[snip]


Yes, but unless I am misreading these, they are
discussing conditions and limits that must exist
IF neutrinos have rest mass. None of these are
discussing WHY physicists believe they must,
or should, have rest mass (the other reason I
have heard is that it would supply the "missing mass" of the universe).


I think you are not reading deep enough. There are theoretical requirements for the class of all neutrinos that they sum to some finite non-zero mass. The internet is full of the stuff. If NOVA got you interested in the topic, then they did a really good job.

Now here we agree, there are theoretical requirements, reasons, for believing that neutrinos have rest mass.

Now I understand that you will think I am changing the subject, but I am trying to form a simile: Teachers still teach Newton in physics. Is it a "huge blunder", that you find hard to believe, that they are still doing this to this day?

I'm trying, but I think you have me :-(
...

The same instant of the supernova process that is
recorded as peak intensity occurs at a different
time than the production of neutrinos.

Yes, but that would merely easily explain their
"beating the photons to Earth" if they travel at c,
just like photons. If they have rest mass, then they
CANNOT travel at c, since that rest mass would
increase to infinity.

Wrong. Rest mass doesn't change with particle
speed. Note the word "rest". Note also that the
physics community at large accepts that mass is
invariant. So that leaves your statement saying
"since that [neutrino's energy] would increase to infinity."

Yes, my typo. But read it with "since that mass
would increase to infinity." Do you see my point?


Yes. And it is just as wrong. "Relativistic mass" increases to infinity, but it is a complex mistake, combining scalar and vector components, and doing neither well. And this term exists only because "common understanding" is such that E = m_o c^2 applies to something other than a mass at rest in your frame.

Wait a minute, are you claiming that the total energy of a neutrino does NOT vary as a function of the neutrino's velocity, that neutrinos form a category of particles that move at c, have a non-zero rest mass, but have a finite energy? It sounds from what you say below ...


Whatever rest mass they have must be increased to a ridiculous degree just to allow them
to "beat" the photons to Earth.


NO change in mass. Change in energy. That is why I adjusted your statement the way I did.

.... that the answer is no, meaning that neutrinos CANNOT move at c, because their energy would be infinite. I THINK you believe that the total energy of a neutrino is its rest mass times gamma, 1/sqrt(1 - v^2/c^2), true? I confess, if physicists have invented a class of particles with a non-zero rest mass that can move at c, but have a finite total energy, it's news to me. Perhaps this is where I'm confused? Or perhaps not, you tell me.

Well, actually, I see from:

http://www.phys.hawaii.edu/~jgl/nuosc_story.html#Implications

"We claim the discovery of neutrino oscillations therefore mass. In short, we observe a deficit of muon neutrinos coming from greater distances and at lower energies, from their production by cosmic rays high in the atmosphere to the detector buried deep underground. The behaviour of this deficit as a function of energy and arrival angle tells us that muon neutrinos oscillate, which is to say that they alternatingly change from one type of neutrino to another as they travel at close to the speed of light."

Close to the speed of light, so no, if neutrinos have rest mass, they do not travel at c, so their total energy is gamma times the rest mass. Later they add that:

"Measuring oscillation tells us the difference between neutrino masses, so the number we find is only a lower limit on the actual neutrino mass. We are measuring a mass of 0.07 +/- 0.04 eV, about one ten millionth of the mass of the electron."


And if I am correct, the difference in arrival times for the neutrinos and the photons matched
predictions which assume that neutrinos travel at
c, not just less than c, which means that difference in speed must make a difference of just minutes or
even seconds over a travel time of 150,000 years!


Clearly ignoring the mechanics of how the neutrinos are formed. You are aware that in "local" cases, the neutrinos arrive *before* the light? Neutrinos are formed *before* the outer sheath is blown away, and maximum intensity occurs when the mass travelling at 0.1c gets large and not-yet too cool.

Maximum intensity of photons or neutrinos? I believe that max neutrino intensity occurs either when the electrons combine with the protons, or shortly after (the density is so great that even neutrinos get delayed). But hey, let's check:

http://zebu.uoregon.edu/~soper/StarDeath/sn1987a.html

The prediction was that the detectors should see neutrinos from SN 1987A for about 10 seconds. One recorded 5.5 seconds, the other 12.5 seconds. This occured at (universal times) 7:36 Feb 23. An observer saw nothing at 9:30 Feb. 23, but an optical plate showed SN 1987A at 10:30 Feb. 23, between 2 and 3 hours after the neutrinos (core collapse), in agreement with theory.

Now, let's say that, in fact, the neutrinos had a 6-hour head start -- contradicting theory -- but that they arrived just 2 hours before the photons, meaning they lost 4 hours due to their less than c velocity. From 167,000 light-years. If we agree with theory then they lost at most 1 hour, but let's be generous and leave it at 4 hours. This places the velocity of a neutrino (assuming 365.25 days per year) at:

365,970,479/365,970,480 of light, or 0.999999997267539 c

Needless to say, I don't have a calculator that can produce gamma, but there's a neat trick that will serve as a close estimate.

0.99726754 -- 13.53646
0.9999726754 -- 135.27292
0.9999997268 -- 1352.834
0.9999999973 -- 13608.

Obviously errors begin to add up in my 10-digit calculator, but also obviously we can take gamma to be 13,520 without too much error. The fact that we took the maximum possible difference in arrival times to be 4 times too high, according to theory, would double this, to 27,040. So, if the rest mass of a neutrino is at least 0.07 eV -- their "middle estimate," but possibly MUCH less than the actual rest mass, since this is only a difference -- then the energy is 946.4 eV with the conservative estimate, or 1,893 eV with the maximum possible difference in arrival times allowed by theory. Now, this is well within the ranges for neutrinos, but it is nased on the most permissible estimates, which has to make you winder.

News flash, I was looking for neutrino energies from SN 1987A, and found an article by Woosley and Weaver from Aug. 1987 SA, where they addressed this issue, and said, "Furthermore, neutrinos of quite different energies arrived within seconds of one another; in contrast, the arrival times of particles with significant mass would have been spread out in order of decreasing energy." and later, "have yielded a firm upper limit on the electron antineutrino's mass: about 20 electron volts."

Okay, okay, the arrival times do not preclude masses < 20 eV, but it is quite possible that other SN events will put much more stringent limits of the possible reat mass, and until I hear that physicists have a reason other than "time-rate for particles with rest mass is zero at c, therefore massless particles must have a time-rate of zero, therefore oscillating neutrinos must have rest mass," I will remain dubious. Remember, I am sure I heard then say just that on NOVA, and neither you nor I have been able to come up with an alternative explanation for the belief that "oscillations = rest mass." And as the articles above show, this IS what physicists believe, we're just not 100% certain WHY they believe it.


So, just to make sure I'm not wasting breath (or fingertips), would you agree that this also
puts a limit on the maximum rest mass of a neutrino?


No real tight limit, no. Accelerating a ba-zillion Mercedes Benz to 0.999999c might be more energy that a supernova can produce. But protons or something smaller, no I don't see that it would be a problem.

As the article just listed shows, it did indeed put a "real tight limit" on the rest mass of a neutrino.


My point was, just how much less than c can the
speed of a neutrino be if it is to reach Earth ahead
of the photons? In your reference, they state that
it took the neutrinos 150,000 years to get here.
Even if the actual collapse of the core (which I believe
is when the neutrinos are produced) occurs a full day
before the light output rises to supernova level (not
necessarily the peak, but enough to show up as a
SN),

There is no reason, and no belief that SN reach peak
in one day. The ejected matter leaves at "0.1c", and
starts to cool sometime later.

Come on, the models predict a certain time from
collapse to noticeable (here on Earth) photon emmision.
I don't remember the number, but I believe it's less than
a day, and even a week would put severe limits on the neutrino rest mass.


I don't think you've got it yet. The neutrinos are formed where in the process?
precrunch, crunch, cook, blast, expansion & cooling to max intensity, expansion & cooling beyond max intensity. We become aware of supernovas by light, and that occurs (hopefully) during the early expansion phases. Keep in mind, light generated in the core of our own Sun takes a month or more to reach the surface where we can see it.

I assume you now know that 2 to 3 hours is the predicted time difference.


the difference in velocity must be so small that
the photons cannot come close to catching up
with the neutrinos even after 150,000 years,
which means the "rest mass" of a neutrino

No need for quotes...

True, I was thinking massless particles, you
caught me.


I wasn't trying to "catch" you. I was trying to point out:
mass = gravitational mass = inertial mass = rest mass =/= relativistic mass


must be so small as to be ridiculous (my bet is
no, that neutrinos have NO rest mass).

Here I was wrong, the rest mass is at most 20 eV.


You'd lose. There are theoretical requirements for
them to have mass.

So? What are those theoretical requirements?


I've provided links. Google will give you a host more.


Has anyone PROVED that they have rest mass?


The data supports them having a mass less than a threshold, and the data supports the entire family having non-zero mass. Science isn't about proof, but *disproof*. We can show something isn't right, or we can show that it survives until the next test. Period. So far theories that predict non-zero neutrino mass are 100%, and ones that don't are being revised.

The fact that so many theories are being revised means nothing by itself, since both the truth, and an error, could cause such revisions.


What I am trying to say is that my GUESS -- and
yes it MIGHT be wrong, but you don't know that, so
why pretend you do --


Thanks. You have made your agenda clear.

WHAT??? I have an opinion that the belief in rest mass MAY be based on a shift-error, I at least thought I heard them say on NOVA just that error, and they unquestionably believe that "oscillations = rest mass," which certainly supports what I believe I heard, and you have what, exactly, to support your apparently completely "faith-based" assertion that the reasons for their belief have NOTHING to do with confusing time-rate for massless particles vs. particles with mass?? Why don't you leave your opinions as to my "agenda" -- when I can assure you, simple pride forces me to immediately change my opinions as soon as verifiable facts force me to -- out of this discussion. Did I call you a "defender of the Holy Experts" simply because you kept asserting that physicists did not make a shift error, even when you provided no backup for that statement? Come on, cutting down your opponent to "prove him wrong" is a very old, and very tiresome, debating trick, so don't do it. I have one "agenda," and it's called REALITY. I liked the NOVA show very much, but as soon as I heard them say that neutrinos must have rest mass because time stops for ANY particle moving at c, I had to conclude that they made an assumption about reality that no theory, as far as you or I know, actually supports. Could it be that the show mistated things? Sure, but to claim so with no supporting evidence -- and a bunch of theories that say neutrinos must have mass is NOT evidence -- is not scientific, nor honest. I won't be so ill-manered as to suggest that you are the one with an agenda, but your statements appear to be based on something other than iron-clad lines of reasoning. Name one physicists who has stated that relativity tells us nothing about the time-rate of massless particles. Just one. One. That will be at least some evidence, unless it turns out that there is a 100 to 1 ration of physicists who think that it DOES tell us that massless particles have a time-rate of zero. That's reality, agenda free. Unless, of course, you call getting at the truth an "agenda." This always pisses me off. Why is it that so many people have to claim that any disagreement with the current beliefs is based on some non-scientific "agenda." Trust me, you are not alone ...


is that the theoretical requirements will turn out to
be based on faulty assumptions. For example, the
idea that since neutrinos transform, they must have
rest mass, because time "stands still" for massless
particles.


*You* have made assumptions, done so despite the experimental data, showing no theoretical premise for doing so, and performed a "shift-error" in insisting that formulae derived for massive particles apply to massless ones. Is that about the size of it?

No. I just hope you have at least a vague understanding of why "no" is in fact the correct answer. The only assumption I can see that I made that was wrong is that the neutrinos from SN 1987A set limits on the rest mass of a neutrino that are lower than they realistically can be, and even that was a "I bet that the data will show," clearly stated as an opinion, not an absolute fact. I see nothing but increasing evidence that physicists have indeed made a shift-error, although they may indeed have, as you CLAIM (and claim your links prove, although I haven't seen it yet), some other reason for believing that "oscillations = rest mass."




This isn't philosophy. What we have are "arguments" and data. Proofs are for non-science disciplines.

That is truly stupid. Proofs are very much for science disciplines, the only caveat being that their reliability isn't absolute, merely 1,000 times better than any hypothesis. This was Newton's point in his 4th "rule of reasoning," it was quite valid then, and still is today.


and while I don't have a problem with that, you act as if they were proofs, when they're clearly
not. Neutrinos MIGHT have rest mass. Most
physicists (!) clearly think so. They have been wrong before, and MIGHT be wrong this time,
especially if they base their belief largely on
the "transform = rest mass," which you have given no proof is something physicists do not
believe, contradicting what at least one
physicist (if I rememeber correctly) said on the
NOVA show.


We can argue "proof" till the cows come home. Theories that predict neutrino mass won. Other theories died, or are being revised. The "flip-flop" between the Sun and Earth was not the deal breaker.

Apparently it was.

...

but I think you and I agree, and disagree with NOVA,
about the ability of massless particles to "change state."

I frankly don't know, Phil. I don't see that that
"massless" equates to "changeless".

The show stated that massless does equate to
changeless, and we both disagree with that
conclusion. Where we disagree is on the point of
how many physicists disagree with you and me.


What does it matter? You are willing to disallow data that require the neutrino to have mass, even though that data is in agreement with theories that predict that mass.

What matters is that you said "I don't see that that 'massless' equates to 'changeless'," then I pointed out that that is what I've been saying all along, and suddenly your response is "What does it matter?" What data did I "disallow?" Do you mean I didn't think, simply because physicists have lots of reasons to believe that neutrinos have mass, that it MUST be true? Do you actually believe that "widespread beliefs" are enough to MAKE things true? Who's being unscientific here? I pointed out a possible flaw with the current beliefs. I have seen nothing from you that shows that the flaw does not actually exist, unless you think that "widespread and increasingly popular opinion" is proof that the flaw does not exist. Let's get real here, if they made the shift-error I have referred to, then there could be a real problem with "all the theories" that predict neutrino mass. What are the odds of that being the case? I should think, or at least hope, low, but it's not the kind of thing you put aside merely because you have "faith" that it isn't true. As a scientist, you make sure that a potentially lethal error has not gone unnoticed, period. There is no other SCIENTIFIC option.



It could be that NOVA is quite correct concerning the beliefs of a significant percentage


I know you hate word games, but "many" starts at "5".

True.



I don't bet. I didn't see the program. I'd bet a transcript was available.
Haven't found it yet, but we need to hear from "real physicists," not NOVA, before you wil suspect that a real problem might exist anyway, so "what does it matter?" (sorry, couldn't resist)


It could be worth checking out, and perhaps even
writing a letter to some magazine or journal if it
turns out that NOVA is correct.


http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/headlights.html
<QUOTE>
There is no sense in saying that time stops when you go at the speed of light. This is not a failing of the theory of relativity. There are no inconsistencies revealed by these questions. They just don't make sense.
<END QUOTE>

http://math.ucr.edu/home/baez/PUB/photonframe
<QUOTE>
If you've been following the above, I am sure you can answer this question yourself--- you -thought- str gave one or more "answers", when it makes no sense in str to ask "how much time would a photon experience.."
<END QUOTE>

I could come up with the necessary three more to make a "many physicists" for you. Will this be necessary?

Interesting how many sites I came up with that established that the speed of light was infinite in the photon's "frame"! Classical frame jumps, and from "edu" sites. The speed of light in the photon's "frame" is indeteminate.

I think none of these are relevant to the issues I have actually raised, as opposed to the issues you seem to think I want to raise. Particles with rest mass don't travel at c, but IF THEY DID their time-rate would HAVE to be zero. Massless particles DO travel at c, and if physicist took what would in fact be true for rest mass particles, and accidently applied that to massless particles, "it would be bad." To claim that I am now suddenly talking about rest mass particles moving at c, for real, is just weird.

Phil

David A. Smith


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