måndag 24 oktober 2011

The Faustian Deal of DLR/Backradiation by Planck

Max Planck just after having made the deal with statistics of quanta in 1900.

In our search for the origin of the idea of DLR or backradiation, let us see what Planck says
in the Preface to the 2nd edition of his Theory of Heat Radiation from 1914 when explaining the difference as compared to the 1st edition from 1907:
  • The main fault of the original treatment was that it began with the classical electrodynamical laws of emission and absorption, whereas later on it became evident that, in order to meet the demand of experimental measurements, the assumption of finite energy elements must be introduced, an assumption which is in direct contradiction to the fundamental ideas of classical electrodynamics.
  • It is true that this inconsistency is greatly reduced by the fact that, in reality, only mean values of energy are taken from classical electrodynamics, while, for the statistical calculation, the real values are used; nevertheless the treatment must, on the whole, have left the reader with the unsatisfactory feeling that it was not clearly to be seen, which of the assumptions made in the beginning could, and which could not, be finally retained.
  • In contrast thereto I have now attempted to treat the subject from the very outset in such a way that none of the laws stated need, later on, be restricted or modified. This presents the advantage that the theory, so far as it is treated here, shows no contradiction in itself, though certainly I do not mean that it does not seem to call for improvements in many respects, as regards both its internal structure and its external form. To treat of the numerous applications, many of them .very important, which the hypothesis of quanta has already found in other parts of physics, I have not regarded as part of my task, still less to discuss all differing opinions.
In short, what Planck does here is to give up his analysis of blackbody radiation based on a classical deterministic continuum physics wave model in the form of Maxwell's equations (classical electrodynamics) for an analysis based on statistical particle physics model borrowed from thermodynamics.

Planck thus replaces deterministic continuum mechanics by statistical mechanics of quanta, an thus finally gives up his long struggle to save his rational soul from the statistics of quanta he had introduced in 1900 with the words:...
  • ...the whole procedure was an act of despair because a theoretical interpretation had to be found at any price, no matter how high that might be
but which had propelled him to become the father of modern physics. Planck thus made a true Faustian deal, which is described in the upcoming book Dr Faustus of Modern Physics.

As concerns DLR/backradiation Planck states on page 1 of his 1914 book:
  • All heat rays which at a given instant pass through
    the same point of the medium are perfectly independent of one
    another, and in order to specify completely the state of the
    radiation the intensity of radiation must be known in all the
    directions, infinite in number, which pass through the point in
    question; for this purpose two opposite directions must be
    considered as distinct, because the radiation in one of them is
    quite independent of the radiation in the other.
  • ...heat rays are identical
    with light rays of the same wave length. The term "heat
    radiation" then, will be applied to all physical phenomena of the
    same nature as light rays.
  • Every light ray is simultaneously a
    heat ray.
  • As a further consequence of this law we shall
    apply to the radiation of heat all the well-known laws of
    experimental optics, especially those of reflection and refraction, as
    well as those relating to the propagation of light.
Planck speaks about "heat rays" as streams of "heat particles", in analogy with "light rays" as streams of "light particles" or "photons", in opposition to light as wave phenomenon.

Newton proposed a particle theory of light which was abandoned when Maxwell showed that light is an electromagnetic wave phenomenon. Planck and Einstein reintroduced the old particle theory because of certain perceived difficulties with Maxwell's wave model.

In Mathematical Physics of Blackbody Radiation I propose a way out of these difficulties
based on a new concept of finite precision computation within Maxwell's wave model and without any particle statistics.

A particle model of light must viewed as primitive, and as a primitive model it is misleading, in particular misleading into an unphysical concept of a two-way transfer of heat energy between bodies of different (or equal) temperature carried by "heat rays" traveling back and forth. Very primitive, indeed. But very popular among CO2 alarmists.

If Planck would have been alive today, we could have asked him about the rationality of his "heat rays" supporting CO2 alarmism. Since this is not the case we have to ask living physicists but they say nothing,
just refer to Planck in his grave.

9 kommentarer:

  1. I'm sorry to say, but there seems to me like my engagement in your model of blackbodies has been a waste of time. You seem to base your justifications on a metaphysical ideal of how you believe nature must behave.

    You asked it yourself in a prior comment, now it's my turn, where is the beef?


  2. So, let me try to summarise your argument.

    1. Planck is dead
    2. There is a cut-off in the spectra of black bodies.
    3. The atmosphere is colder than the Earth
    4. Therefore, radiation from the atmosphere does not exist
    5. If it exists, it is not absorbed by the Earth
    6. If it is absorbed, it doesn't transfer any energy

    Is that correct?

  3. The beef is big: rational determinism vs irrational statistics.

  4. 1-3 yes. 4-6 have to formulated more precisely, I do not say that.

  5. Claes wrote:
    The beef is big: rational determinism vs irrational statistics.

    Well, in my point of view this has no substance at all.

    How you wish nature to behave should have no restrictions on how nature behaves, at least if we wish to keep rationality.

    The this world view vs that world view discussion is a metaphysical one and has no infliction on the true nature of the world. That is my own rational view.

    So for me, until you come up with a more convincing argument based on discernible empirical results, the beef lies between nothing to really slim, at best.


  6. It is up to you to find something useful in what I am saying. You don't have to and I am not insisting that you should.

  7. There is one thing that bothered me, and a couple of moments ago, when I was out on my daily run, it manifested itself for me.

    You have claimed that one of the big problems in what we are discussing is that heat can not go from a colder body to a warmer and that this is prevented by thermodynamics. But is it really?

    Imagine two bodies, one hot A and one colder B. Say that a net exchange of heat is transmitted that is dQ = dQ_A - dQ_B from body A to body B.

    We then have,

    dQ/T_B - dQ/T_A = dQ(1/dT_dB - 1/dT_dA) =dQ(T_A - T_B)/(T_A*TB) > 0,

    given that body A gives away more heat then body B.

    So there is no problem with the thermodynamics when we have two radiating bodies where one is hotter.


  8. Are you saying that heat is transferred from hot to cold?

  9. Claes wrote:
    Are you saying that heat is transferred from hot to cold?

    To be picky heat is transmitted in both directions, but the net heat is transferred from hot to cold. (Just read the equations...)

    But seriously, this isn't a semantic question, it is a question of thermodynamics.