Re: Photon momentum [Was Re: Setterfield's c-decay and the frequency of light]

From: Bill Hobba (bhobba_at_rubbish.net.au)
Date: 12/10/04 

Date: Fri, 10 Dec 2004 01:05:10 GMT

"N:dlzc D:aol T:com (dlzc)" <N: dlzc1 D:cox T:net@nospam.com> wrote in
message news:qb6ud.1467$Af.1371@fed1read07...
> Dear sheperdmoon:
>
> <shepherdmoon@yahoo.com> wrote in message
> news:1102623049.172645.168510@f14g2000cwb.googlegroups.com...
> > N:dlzc D:aol T:com (dlzc) wrote:
> ...
> >> > Along those lines, I noticed that the equation for a
> >> > photon's momentum
> >> > (p) is:
> >> >
> >> > p = h/lambda
> >> >
> >> > where
> >> > h = Planck's constant
> >> > lambda = photon's wavelength
> >> >
> >> > So it seems to me that I have an airtight object
> >> > to my opponent's claim that the speed of light was
> >> > higher in the past because the frequency was
> >> > higher while the wavelength remained constant. Look
> >> > at my thinking, for argument's sake.
> >>
> >> No. c is always c.
> >
> > I don't follow you here.
>
> Both the frequency AND the wavelength are altered. c is always c.
>
> > This is what Setterfield's paper says (from
> > the introduction):
> >
> > ---
> > If indeed the velocity of light has changed or is changing,
>
> This would violate conservation of energy locally.
>
> > a certain
> > set of related other physical "constants" have changed as well. The
> > authors have not set out to "prove" that this is indeed the case. They
> > have however amassed and carefully studied a great body of data
>
> This is indeed the case.
>
> > that
> > suggests that the some of most "sacred" of the physical constants are
> > not constant after all.
>
> They do NOT suggest this. They do highlight clearly that standards and
> transfer standards (ie. metrology) has changed. Some early measurements
of
> c were less than today's established value.
>
> > Their report is written in accord with
> > perfectly orthodox scientific standards. That is, they have collected
> > and analyzed the available data and formed a hypothesis.
>
> Backwards, actually. They had a hypothesis, and they gathered the data to
> support it.
>
> > This
> > hypothesis (that the velocity of light has decreased with time) is
> > testable.
>
> It is not testable. The SPEED of light is established, and the meter is
> derived from it. No decrease in c can be observed, and cannot be
observed,
> since 1983.
>
> > It is a perfectly valid hypothesis until further data proves
> > otherwise.
>
> Like the definition of the meter, which obviates his entire argument.
>
> > I believe it is timely and appropriate to call wider
> > attention to this hitherto little known investigation. This report is
> > therefore presented to invite discussion, comment, rebuttal, and
> > hopefully to provoke researchers to look for further evidence which
> > could support or refute the authors' conclusions.
> > ---
> > http://www.setterfield.org/report/report.html
> >
> > It states that the hypothesis is "that the velocity of light has
> > decreased with time."
>
> Actually it purports that this is the *conclusion*. The hypothesis is
that
> all sacred constants point to creation 6000 years ago.
>
> ...
> >> > I think there should be an observable difference between
> >> > what is generally claimed by scientists -- that c has been
> >> > constant for eons if not right back to the Big Bang -- and
> >> > what Setterfield claims -- that c has been dropping.
> >>
> >> *Measurements* of c overall have been. But this is a
> >> metrology problem.
> >
> > As I said above, I don't follow. I think I see what you are assuming,
> > namely, that light has been moving with constant speed all along, but
> > our measurements of time have been changing due to cosmological
> > changes. These changes in time measurement have in turn affected our
> > measurements of c's velocity.
>
> Not exactly. The changes in time measurement affect (to some tiny extent)
> previosuly established measurements. Red shifting of ancient light, as
the
> prime example.
>
> > But even if the hypothesis is that the measurement of c is just a
> > metrology problem, which the above Setterfield quotation appears to
> > contradict,
>
> It is his intent to support creation 6000 years ago. What else CAN he
say?
>
> > then you would still see other corresponding metrology
> > problems in the observed momentum of photons throughout the universe.
>
> And the momentum is in fact reduced. That is what red shift does. The
> photons are not affected, but the relationship between the emitter and the
> receiver is. Photons always travel at *local* c. Local in both space...
> and time.
>
> >> > Can someone confirm what the implications would
> >> > be of a 10 million-fold increase in photon momentum
> >> > across the universe over 6,000-10,000 years (the YEC
> >> > claim for the age of the universe)?
> >>
> >> The momentum is *reduced*, not increased. Longer
> >> wavelength equates to lower momentum.
> >
> > In other cases, Setterfield appears to have one constant changing to
> > offset another, so that he can then claim that there would be no
> > observed difference (e.g., hc is a constant).
>
> He *does* (and *did*) a through job of evaluating all the constants, yes.
> And not only are they tied to alpha (which has been documented to be
*very*
> constant), but they are tied to metrology. Since alpha is dimensionless,
> changes in the meter would not affect alpha. Likewise the second and the
> kilogram. If calibrations are carried out with the same fastideousness,
> and are timely, alpha should appear constant. And it is.

Bingo. To the original poster David has hit one of the issues with the idea
of changing constants right on the head with his comments about alpha. As I
have been trying to get across to you the exact value of constants like c,
h, the permitvity of space etc are meaningless because they can always be
set to one by a suitable choice of units. When that is done in QED only one
dimensionless constant remains - the fine structure constant alpha - and
that has been shown to be constant to at least .6 parts per million.

The other stuff that David has been alluding to indicates the person who
wrote the paper does not understand fundamental physics. If you find
difficulty in countering the arguments of this person ask them to post here.
We have some genuine physicists (I am not one) who regularly post and I have
no doubt they will be able to tear his paper to shreds. David has provided
enough information to indicate it is basically rubbish written by someone
who wants to put the cart before the horse ie justify something they have
made their minds about beforehand. From what David has written it is
doubtful they even understand the role of c in modern physics - it is not
really the speed of light - if it is an experimental matter - it is a
natural constant whose existence is implied by the POR. To understand this
you might like to have a look at the following:

http://arxiv.org/abs/physics/0110076,
and ancient, but I still think excellent post by Tom Roberts
http://groups.google.com/groups?hl=en&lr=&c2coff=1&selm=54jfst%24glp%40ssbunews.ih.lucent.com
and chapter 10 of
http://www.courses.fas.harvard.edu/~phys16/Textbook/
under the heading of Relativity without c.

Thanks
Bill

>
> > I suspect these
> > adjustments are made so that Setterfield's hypothesis will appear not
> > to contradict data we have observed for c = 299,792,458 m/s.
>
> Not just observed (in 1983), but established. c will not have any other
> value in a vacuum, unless some committee gets the "world" to agree to the
> new standard.
>
> > But in the case of momentum, the claim is that h is rising (because c
> > is dropping), and that lambda has remained constant. Lambda has to
> > remain constant because, my opponent claims, frequency was higher in
> > the past, based on the photon speed equation
> >
> > c = frequency * wavelength
>
> This is not the case, however. Time dilation of the duration of Type I
> supernovae is in proportion to teh redshift of its characterisitc light
> spectra. The frequency is slowed, in proportion to the change in
> wavelength. Net-net is: c_now = c_then. *We* are different.
>
> > It is the frequency increase that Setterfield uses to claim that c was
> > higher in the past. As I understand the argument, wavelength cannot
> > change because that would lead to observable consequences (assuming the
> > need to maintain the literal biblical account) such as the Garden of
> > Eden being fried by high-energy radiation etc.
>
> Yes, well. Adam's children did not marry each other, but they did marry.
> The Bible's Old Testament is at best a public health manual.
>
> > Thus, if h is higher now than in the past, and lambda has remained
> > constant, then p is higher how than in the past according to p =
> > h/lambda, because the numerator is growing while the denominator stays
> > the same.
>
> The momentum *must* be the same. The charge on the electron and proton
> hasn't changed (by his claim), and the discrete "orbitals" of hydrogen
> haven't changed. *We* have (more correctly, *Now* has).
>
> ...
> >> > It sounds as if Setterfield may be saying that photon
> >> > momentum does vary. But even if this is true, then that
> >> > means photon energy is not conserved, which contradicts
> >> > his claim that it is conserved.
> >>
> >> Conservation of energy in an expanding Universe is not required.
> >>
> >
> > Honestly, I don't know enough physics to say that conservation is or is
> > not required in an expanding universe. But I do know that Setterfield
> > claims that E (photon energy) has remained constant (he says it above),
> > which from what I have read implies that momentum has remained
> > constant, too.
>
> Only if you discount his change in h.
>
> > And I am making what I think is a reasonable logical
> > assumption, namely, that a universe with a photon momentum constant
> > over time would look different from a universe with a photon momentum
> > that has increased over time.
>
> I think you need to look at "when" that momentum is established. Old
light
> has lower momentum, when it was generated from a similar "jump". "Old"
and
> 'similar "jump" ' being compared to "now".
>
> > My momentum example addresses only Setterfield's claim that a value has
> > remained constant when it appears impossible that it could have,
> > according to the equations.
>
> You have to make inferences that he is not willing to make. Nor will he
be
> willing to change. His work is *huge* (in some sense), and is literally
> man years of effort. Its purpose vanishes, if you convince him...
>
> Still wish to assail the edifice? It will not change...
>
> David A. Smith
>
>

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