Talk:Rayleigh–Jeans law

message: There is a potential confusion: Energy per unit volume, which is what one usually means by energy density, has different units from energy density per unit wavelength which, in turn, has different units from energy density per unit frequency. It is stated that the function given is the energy density which cannot be the energy per unit volume by dimensional analysis. Furthermore, the Plank law originally written had wavelength-cubed dependence in the denominator which I changed to wavelength-to-the-fifth. This is necessary to get the first equation as the short-wavelength limit. Which form of the energy `density' one uses is a matter of convention but because of non-trivial Jacobian factors which appear in going from one to the other, the functional dependence of these forms is quite different. —The preceding unsigned comment was added by Wdlinch3 (talk • contribs) 18:11, 22 March 2007 (UTC)
thread_title:  Energy densities 

message: The stuff in the following link should be added:
68.145.103.0 (talk) 04:12, 8 January 2008 (UTC)
thread_title:  Electromagnetic modes

message: I notice that Rayleigh limit redirects here.  I think that is misleading: it should be set to Angular resolution instead. Any thoughts or objections before I proceed? CrispMuncher (talk) 19:19, 13 October 2009 (UTC)
replies: text: Sounds fine.  I think that the angular resolution thing is usually called the Rayleigh criterion (which does redirect to angular resolution), but a quick google suggests that the term "Rayleigh limit" is used both as an alternative name for Rayleigh criterion, or for the limit to the stability of charged droplets of liquid (see http://phd.marginean.net/rayleigh.html).  (Maybe both about equally?)  Neither of these have anything to do with the Rayleigh–Jeans law, so it definitely shouldn't redirect here!  Djr32 (talk) 20:20, 13 October 2009 (UTC)
thread_title:  Rayleigh limit 

message: The units on the graph are given as J m^-2 Sr^-1 when radiance is given in W m^-2 Sr^-1. Is someone able to change this graph. Its either a mistake or at best a confusing abstraction.  —Preceding unsigned comment added by Phuech (talk • contribs) 12:41, 9 July 2010 (UTC)
thread_title:  Units of first plot 

message: :B_\lambda(T) = \frac{2 c k T}{\lambda^4},
and 
:B_\nu(T) = \frac{2 \nu^2 k T}{c^2}.
seem to have different dimensions.
mmkay mm?  —Preceding unsigned comment added by 157.193.3.7 (talk) 17:14, 24 April 2011 (UTC)
replies: text:  Yes, conversion with nu = c/lambda was made incorrectly in entire article Dims (talk) 09:49, 1 December 2019 (UTC)
thread_title:  incompatible expressions? 

message: It is believed that the Rayleigh-Jeans law strongly disagrees with experimental results at high frequencies owing to the inability  to use classical concepts to describe the distribution of energy in the spectrum of the black body. In fact, the cause is incorrect use of the differential characteristics to describe the real processes.
The Rayleigh-Jeans law contains three misconceptions. This law does not take into account the limitation of real processes in speed, it does not take into account the limitation of the real processes in energy and the uniform distribution of probability density (any oscillator can have any energy with equal probability) is not suitable to describe the processes that obey the normal distribution law.
Reason of the error can be understood just from the classic concept of the linear oscillator. One picture is worth a thousand words. The most obvious explanation would look like with images.
Energy of a linear oscillator is the sum of the kinetic and potential energy which changing in the opposite phase (on the image: Ek - kinetic energy, Ep - potential energy, t - time) and does not depend from time.
Therefore, differential characteristics (instantaneous speed, instantaneous impulse and instantaneous energy) can be used for calculate the energy of a linear oscillator. In the Rayleigh-Jeans law is assumed that the energy of a linear oscillator is dependent only from temperature (on the image: E - energy, T - temperature, t - time).
However, the energy of a linear oscillator can be completely consist only of kinetic energy, or only of the potential energy.  Real time is needed for move from one energy state to another. For radiation of low frequency speed of transition is real and description in the Rayleigh–Jeans law is valid. But with increasing frequency time for the transitions between energy states must be less and less. Instantaneous speed (and instantaneous energy) of the such oscillator tends to infinity with increasing frequency.
This is the fatal error for the linear oscillator. Therefore it requires a speed limit for transition of a linear oscillator from one energy state to another for high frequency radiation. Looks like nobody noticed how beautifully Planck introduced the dependence of the real process from time - the energy of the linear oscillator (kinetic energy) can not be greater than hν at any temperature.
Such explanation could been done long ago (probably hundred years ago). In addition, one would assume (eighty years ago) that there is another solution when the distribution of energy in the spectrum of black body is described by Fermi-Dirac statistics /link/. Linear oscillator has limit by the energy (potential energy) directly in this case. Leonid 2 (talk) 06:19, 8 May 2011 (UTC)
thread_title:  Rayleigh-Jeans law and the fatal error for the linear oscillator 

message: What is 8 mK supposed to be ?Eregli bob (talk) 07:18, 26 May 2011 (UTC)
replies: text: Millikelvins, i.e. 8 mK = 0.008 K = -273.142 °C--SiriusB (talk) 12:46, 16 February 2012 (UTC)
thread_title:  8 mK 

message: "In 1900 Max Planck empirically obtained an expression for black-body radiation" - Did he 'empirically' ...?
--Gozo032 (talk) 15:53, 31 August 2020 (UTC)
thread_title:  Empirically 

message: I would like to point out that :Category:Obsolete theories in physics is still unverified within the article. I have stated before that I am comfortable citing 's source about how this law was , but there is no mention of it being  or  , and the book that  provided is not referenced in the article. Both of these things should be done for this category to be verified. Unfortunately,  has protected this article in a version that includes the category which  has challenged and  has repeatedly added without citation      . , could you explain this decision?      — Freoh 18:12, 17 March 2023 (UTC)
replies: text: Simple. See here. Daniel Case (talk) 18:15, 17 March 2023 (UTC)
replies: text: Thanks for the clarification, I had not seen that essay before.      — Freoh 18:23, 17 March 2023 (UTC)
thread_title: Still uncited