Talk:Poynting–Robertson effect

message: I may be wrong but so far as I can tell the given equation on the page has no source, and from sources in my own search, papers and lectures appear to have a much lengthier/involved rendition. Is this equation correct? I'm wanting to use it in my own writing but I'm failing to verify if it is accurate and I'm not of the needed skillset to check if the other forms do simplify to the one given here. The inclusion of a derivation would be well received I'm sure. 
Examples of variations to the equation:
slide 11 of this
At the bottom of this NASA paper
160.5.189.168 (talk) 18:21, 25 April 2019 (UTC)
thread_title:  Equation Origin 

message: The "solar system perspective" explanation is flawed. The re-radiation does not contribute to the Poynting-Robertson effest. This is most easily seen by removing the sun's radiation: A glowing lightbulb flying through space would have to slow down on its own by this radiation effect (which it obviously does not). In the solar system perspective, the effect is still that the sun's radiation absorbed by the particle does not carry an impulse in the particle's direction of movement; thus, by absorption, the particle's mass, but not its impulse (in that direction) is increased: It is slowed.
Unfortunately, this mistake managed to find its way into parts of the literature, probably based on the Poynting article cited, which predates relativity theory and is ether-based. Robertson seems to have seen this problem, but I'm not sure whether he concerns himself with the solar system perspective at all. I'm no physicist myself and therefore don't know all the literature; could someone more qualified than me rewrite that section and cite an adequate reference? Yours, Huon 12:44, 3 June 2006 (UTC)
thread_title:  Re-radiation 

message: Hi, I have been carefully studying the PR drag and I would like to add a few words on this discussion. Let me point them out as numbered statements which may help to further discussion :
1.- The main contribution of the PR drag is the special relativistic light aberration effect. Let us assume that in a given reference system, there is a constant radiation field perpendicular to the motion of a particle; then in the comobile reference system of the particle, the radiation will be tilted a small angle, as it happens when you go by car and it is raining (form the driver's point of view, the rain comes to his front glass). In this picture, it is easy to see that the radiation field effectively breaks the particle. The same is applicable for short timescales to an orbiting dust grain. Since the PR drag is small, one can assume that it quasistatically brakes de particle, changing slowly its angular momentum dL/dt = m r x dv/dt
2.- Absorption/radiation is not required. Even if the light is simply reflected, the PR will take place. Again, imagine you drive a car and icy drops fall on the car. They exchange momentum with your car glasses even if they are bounced by the glass. In fact, reflection exchanges more momentum than absorption. The increase in mass is negligible in this scale, and the PR effect has nothing to do with this. The expression of the PR effect should include a multiplicative factor of the form (1+k), where k is the "albedo" constant (say, the fraction of radiation that is reflected with respect to the incident one). 
3.- If there is absoption, there will be some isotropic radiation, but only on the instantaneously comoving reference system of the particle. As seen from the Solar System reference system, you have a time dependent radiation field form the particle which certainly dissipates angular momentum. This will, for sure, cause a loose of angular momentum. At this point i am not sure, but i have the feeling that it works at a higher v/c order (PR drag is a v/c^1 effect), thus producing negligible effects. This should be computed accurately since it depends (for example) on the albedo constant k. 
I will check more carefully the literature. It may happen that the original Poynting papers gave a wrong description of the effect (they assumed there was eather!!!), but qualitatively correct answers. Most likely, a more modern review on the topic should be used and cited.
Astre 23:34, 17 Octubre 2007 (UTC)
:While I'm in no way certain right now, I believe Poynting's result is quantitatively off by a factor 2 or so, but Robertson's is correct. Concerning the angular momentum: In the Solar System reference system, the radiation field dissipates angular momentum, but it also dissipates mass, and the effects cancel each other out and don't contribute to PR drag. As Rschr said above, turn off the sun, and a lightbulb flying through space doesn't slow down even though it has a similar time-dependent radiation field. By the way, since Poynting was able to discover the effect before using relativity, it can't be primarily relativity-based as you claim under 1.-  Yours, Huon 23:40, 17 October 2007 (UTC)
replies: text: @Astre; re 2: "simply reflected" can mean many things --- that's how solar sails work! If the mirror normal is radial, then there is no angular momentum transfer, but there is radiation pressure; if the mirror normal is tangential, then we get a large PR effect; and if the mirror normal is orbit-binormal, ... then I think there's nothing going on. Jcmckeown (talk) 23:45, 20 September 2016 (UTC)
thread_title:  Misleading arguments in this discussion

message: The Royal Philosophical Society Archives are now on-line going back to the mid 1600's. 
The original Poynting paper is sharp text on clear background vs the poorly-done copy-machine version.
The Astronomical Society references are a bit more difficult to find.
Hpfeil (talk) 16:25, 27 October 2011 (UTC)
thread_title:  Royal Philosophical Society Archives 

message: Please could mention be made of where the angular momentum goes? Does the Poynting–Robertson effect, ever so slightly, cause the sun to spin faster? Or is it somehow radiated into deep space? The answer isn’t obvious to this scientific reader, and might be even less obvious to some other readers. JDAWiseman (talk) 20:59, 2 May 2018 (UTC)
thread_title:  Angular momentum 

message: Exactly like the Sun seen by an astronomer the dust particle receives the light with an aberration effect poynting (pun intended) forward its own movement AND also submitted to a retardation effect poynting backward proportional to the remoteness of the source. Only the vectorial sum of these two causes can yield the actual direction of the light pressure.  — Preceding unsigned comment added by 37.164.218.13 (talk) 11:54, 14 January 2022 (UTC)
thread_title:  Retardation