Established Member
See this paper
Summary:
-Anything with a significant redshift due to the Compton Effect would have significant blurring since it would be scattered from off-line of sight (the Compton Effect is dependent on scattering of photons).
-Compton Effect predicts z proportional to 1/wavelength whereas the cosmological redshift shows no such dependence.
Therefore, we should not conclude that the Compton Effect explains the redshift-distance relation.
Established Member
The report assumes that the photon deflection deflects the ExH vector of the photon. But this is a throwback to the old way of explaining the Compton effect as Thomson scattering. Thomson scattering depended on the charge of the electron and the varying electric field of the e-m wave. Compton scattering is a direct challenge to this interpretation and instead takes the extreme quantum mechanic view of the process. The "scattering" is entirely explained in terms of conservation of energy and momentum and has no electromagnetic changes involved. In fact, the compton effect is explained as occuring for neutral as well as charged particles. The presence of the "unshifted line" is explained as scattering off the entire target atom which has an insignificantly small wavelength change because the change is inversely proportional to the mass of the target. When light traverses a transparent medium, it is not blurred even though the light interacts so strongly with the medium it is slowed (according to the index of refraction of the medium). But there is no blurring because the ExH vector is unchanged by the interaction. We can see deflections of the photons in the near field with energy detectors, but in the far field the wavefront is reconstructed via Huygens secondary wavelets to proceed in the ExH direction with9out blurring. To cause blurring you must change the ExH vector like is done in little mirrors or fog droplets. Feyman made some contributions in this theory. The paper is wrong in that it assumes that the blurring must occur in the far field just like it does in the near field and does not consider the reconstruction of the wavefront. The author should read up on radar imaging theory to get the difference between far field and near field imaging. When I worked on the Shuttle Imaging Radar this was a major concern. We had to test on antenna ranges that were large enough to get the far field data and reconstruct the reflected image back to the SAR. In the near field we indeed got blurring. The answer to the blurring problem is not so hard once you understand group velocity.
Hey, if the Compton effect doesn't cause a red shift then why did Compton himself ascibe the solar red shift to the Compton effect. Don't you think he would've known about this?
<font size=-1>[ This Message was edited by: John Kierein on 2003-01-27 13:38 ]</font>
Established Member
John Kierein is dead wrong. Thomson scattering is the low-photon-energy limit of Compton scattering.
And light going through a medium will have its wavelength changed, but not its frequency. And a change of frequency is necessary for producing a redshift.
And where is Compton supposed to have claimed that the Sun's redshift is due to Compton scattering?
Even if it was, then that is no counterargument, because the scattering in the Sun's atmosphere blurs details of what's below.
Established Member
Well, JK, for starters you didn't address a single one of the points. The report nowhere assumes a deflection of the EXH vector (by the way, for a vacuum you've got an EXB vector). It doesn't refer to any sort of conditional charge relationship at all. All it does is model the mechanics of a scattering. A scattering occurs with a change in angle. That's the physical definition of scattering.
Frankly, if you have a change in the momentum of the vector that means you need to have a change in the Poynting vector (or it's quantum mechanical equivalent value). This will mean that you end up scattering your photon. Thus the term Compton "Scattering".
Of course, then JK goes onto "reconstructing wavefronts" but offers nothing in the way of support that such a mechanism could take back the deflection, as it were, and still allow for a change in the energy signal. Does this make sense to anybody reading?
Then JK throws in a red herring about radar imaging which has absolutely nothing to do with weak Compton Scattering. The paper is utterly basic and easy to understand, but he doesn't address any of the fundamental arguments. What is the equation for the scattering, JK, if the authors got it wrong?
It's also apparent he didn't read the paper because the very last paragraph states that Compton's explanation for the limb effect on the sun doesn't say anything about cosmology. I'll leave it to the gentle reader to find it. If anybody has trouble reading it, they can get in touch with me.
Frankly, it's funny that JK hasn't read this paper since it references one of his own!
Established Member
how about light traversing a medium that absorbs light then reemits it at a lower frequency ??
in this case we have redshift with no Doppler or Compton .
Established Member
I believe that would be equivalent to Raman scattering. I can see two problems with trying to explain redshifts with this. First, the direction that the light is re-emitted will not likely be in the same direction as the original direction so an object would still be blurred. Second, the resulting spectrum would be very different than the original object. We would see nothing like the spectral lines of hydrogen (redshifted or not).On 2003-01-27 15:03, cable wrote:
how about light traversing a medium that absorbs light then reemits it at a lower frequency ??
in this case we have redshift with no Doppler or Compton .
Established Member
Right, cable, that's a separate issue. Of course, the problem with such a model is that absorption and reemmission at a lower frequency implies a net increase in the energy of the absorber. So this would have to be a completely new and strange substance, see that would have to be in tremendous conspiracy to get everything to work out in the right way.
Established Member
lpetrich knows not whereof he speaks. The frequency must change if the wavelength changes. It's basically the same thing. Lf =c.
JS is right that the ExH vector is the same as the Poynting vector. There are attempts to marry the Thomson scattering with Compton scattering, but the data do not support this only theoretical attempt. Thomson scattering was thought to be the mechanism for interaction of electrons with electromagnetic waves on a theoretical basis. This mechanism was that the wave was composed of varying electric and magnetic fields. The theory is similar to that of an antenna picking up a signal by having conductive electrons in a wire respond to the varying electric field of the wave and thus generate a current of the same signal. The theory is that the electron responds to the incoming varying electric field and vibrates up and down at the same frequency as the incoming wave, thus generating a new isotropic wave and causing blurring. This theory is not correct according to Compton. This theory predicts the scattering to be isotropic from the scatterer and definitely will not work for scattering from neutral particles. It does not predict a change in wavelength, although there have been attempts to modify the theory to make this work by classical physicists.
On the other hand, the Compton effect has nothing to do with the charge of the electron or the varying electric field of the photon. It is entirely described by billiard ball mechanics and gives the resulting acceleration of the electron to a new velocity with a new kinetic energy and a corresponding loss of energy of the photon to a shorter wavelength. It correctly predicts the change in wavelength of the photon and the energy of the electron. It also occurs for scattering from neutral particles unlike the previously wrong description of the Thomson scattering as being the mechanism, which is still taught in schools despite this. The crossection of the electron for the probability of the interaction is probably correct.
Now the author correctly says that there must be a change in the momentum vector for the Compton effect to occur. But he presumes that if the individual photon changes direction that we would therefore see blurring. This is where we disagree. There is nothing in the Compton effect to change the ExH (or ExB) vector. There are no electromagnetic effects to make that occur. Admittedly the individual photon will take a slightly longer path when encountering material such as a transparent medium, but this only results in a slowing of the group velocity of the wavefront composed of many photons, each one of which is travelling at c despite the fact that the wavefront is travelling at less than c. What we "see" or image is the ExH vector of the wavefront, but we can detect the energy of individual photons with energy detectors. This is the strange duality of light where it acts both as a wave and a particle. We see the wavefront and we can detect the particle. The wavefront is reconstructed by multiple photons by Huygens secondary wavelets that act like the scattering centers. These Huygens secondary wavelets explain the interference patterns we see when light goes through a slit.
Anybody who denies that the Compton effect exists is incorrect. It won a Nobel prize for Compton. Compton said the red shift on the sun was due to the Compton effect. It is normally seen in the lab only at short wavelengths because at these wavelengths the energy change is very large percentage of the energy of the energy of the already very energetic photon and it is easily observed. Also it is very hard to get free electrons in the lab to be a target, they are almost all tied up in various energy levels of atoms and molecules, so if the photon is very short wavelength it can eject the electron from the atom (by being ionizing radiation) and then immediately scatter the photon from the electron. But if there are already free electrons in a highly ionized plasma, then the Compton effect works for all wavelengths. Unfortunately, for longer wavelengths the change in wavelength is not a very big portion of the energy of the original photon and it takes a very large number of electrons and "scatterings" to produce a decently measurable shift. So this is very hard to do in the laboratory, but is seen in the sun's atmosphere where we get a small, but measurable shift from all the electrons along the line of sight in the sun's atmosphere.
This paper gives the proportionality to wavelength that the author couldn't find.
http://www.geocities.com/CapeCanaver...5/compton.html
<font size=-1>[ This Message was edited by: John Kierein on 2003-01-27 15:29 ]</font>
<font size=-1>[ This Message was edited by: John Kierein on 2003-01-27 15:33 ]</font>
<font size=-1>[ This Message was edited by: John Kierein on 2003-01-27 15:37 ]</font>
<font size=-1>[ This Message was edited by: John Kierein on 2003-01-27 15:54 ]</font>
Established Member
John, the paper cited below deals with this point:On 2003-01-27 15:28, John Kierein wrote:
. . .
There are attempts to marry the Thomson scattering with Compton scattering, but the data do not support this only theoretical attempt. Thomson scattering was thought to be the mechanism for interaction of electrons with electromagnetic waves on a theoretical basis. This mechanism was that the wave was composed of varying electric and magnetic fields. The theory is similar to that of an antenna picking up a signal by having conductive electrons in a wire respond to the varying electric field of the wave and thus generate a current of the same signal. The theory is that the electron responds to the incoming varying electric field and vibrates up and down at the same frequency as the incoming wave, thus generating a new isotropic wave and causing blurring. This theory is not correct according to Compton. This theory predicts the scattering to be isotropic from the scatterer and definitely will not work for scattering from neutral particles. It does not predict a change in wavelength, although there have been attempts to modify the theory to make this work by classical physicists.
On the other hand, the Compton effect has nothing to do with the charge of the electron or the varying electric field of the photon. It is entirely described by billiard ball mechanics and gives the resulting acceleration of the electron to a new velocity with a new kinetic energy and a corresponding loss of energy of the photon to a shorter wavelength. It correctly predicts the change in wavelength of the photon and the energy of the electron. It also occurs for scattering from neutral particles unlike the previously wrong description of the Thomson scattering as being the mechanism, which is still taught in schools despite this.
. . .
http://www.phys.ksu.edu/~cdlin/articles/cdl/j104.pdf
This paper shows that Compton scattering in fact does depend on the charge state, so that there is more than just the billiard ball dynamics.
The next question I would have for you is this: if Compton scattering is not based on E&M, what force is it based on? This is multiple choice: has to be either (a) strong nuclear force; (b) weak nuclear force; (c) gravity; or (d)E&M. It's obviously not the strong force (e-'s do not interact this way) or gravity. What does that leave you?
<font size=-1>[ This Message was edited by: Zathras on 2003-01-27 15:41 ]</font>
Established Member
Did you read the paper, John? Be honest.
here's a quote from yours:
This cos q is exactly the problem number one. If you don't think that Compton scattering takes light from one direction and shifts it into another you don't understand your own equations. Even billiard balls deflect, for goodness sake.where Dli is the shift per interaction given by the familiar Compton formula:
Dli = h (1 - cos q) / mc (3)
where h is Planck's constant, m is the mass of the particle (electron), c is the velocity of light, and q is the angle of deflection of the photon velocity vector. Ni in equation 2 is the number of Compton
interactions occurring, so that cos q is the "average cos q" observed over the large number of interactions involved.
The rest of the argument stands, then. It is done using that very equation you state as the familiar COmpton formula. It is utterly simple and an elegent proof that we should expect a wavelength dependence on z and furthermore we should expect scattering of photons. In fact, you even derive yourself that H is dependent on the angle. You've offered nothing in the way of proof as to how to get rid of this other than saying you can "average" over all angles. Ridiculous. This is junk mathematics and an attempt to placate your own prejudices against a Doppler velocity.
We know for a fact that redshift of the sun is accounted for by at least two different and maybe three different factors. Chalking it all up to Compton Scattering is downright absurd.
Established Member
Hey, I just spent a long answer saying that the fact that the photon deflects doesn't cause blurring. I didn't deny that the photon deflects, just that that doesn't cause blurring. Re-read what I wrote. It has to do with the dual wave and particle nature of light. The particle deflects, but the wavefront doesn't. Reber used a random walk argument to show this. Look at his J. Franklin Research paper to see this.
Banned
Good observation i have introduce Paul Marmet works explaining a Non Cosmological Redshift introducing an aspect non considered in Compton effect. ie- In the usual treatment of the Compton effect, bremsstrahlung is neglected.On 2003-01-27 15:03, cable wrote:
how about light traversing a medium that absorbs light then reemits it at a lower frequency ??
in this case we have redshift with no Doppler or Compton .
http://www.newtonphysics.on.ca/HUBBLE/Hubble.html
And a model introducing an Intrinsic Redshift of Z 3 explaining the Layman Alpha Forest
http://216.239.53.100/search?q=cache...hl=en&ie=UTF-8
Recent progress with cosmological hydro-simulations based on hierarchical
structure formation models has led to important insights into the physical struc-
tures giving rise to the forest. *If these ideas are correct, a truly inter- and pro-
togalactic medium at high redshift Z 3*
the main repository of baryons
collapses under the influence of dark matter gravity into flattened or filamentary
structures, which are seen in absorption against background QSOs. With decreas-
ing redshift, galaxies forming in the denser regions may contribute an increasing
part of the Ly
absorption cross section.
PDF version:
http://lithops.as.arizona.edu/~jill/...f/rauch267.pdf
Established Member
JK, using Reber as your source for explaining cross-spectral redshifts is ludicrous. He has been sufficiently debunked in the past and I'm not going to entertain you with a reprisal.
Using the wavefront, ladies and gentlemen, proves that JK has extreme sour grapes. Herein lies the problem...
JK says he wants to use Compton Scattering. Wonderful, say we, where does Compton Scattering take place? Why for quantum-like particles called photons. It is inversely dependent upon wavelength so we expect to see it mostly in high-energy photons (X-rays are where we first confirmed Compton scattering).
If we move to the radio, which is where Reber lived most of his life, what we find is that Compton Scattering just doesn't happen. The fact of the matter is, the effect is so small you just won't get it. There is a wavelength dependence on the scattering (notice JK does not deal with this problem). So, great, you might be able to show that for a significantly delocated wavefront you get no net scattering... but then you have no scattering and certainly no energy transfer. This is where Reber fell to pieces and could not come up with a decent explanation.
So, this is the problem. For sufficiently high enough energy photons the wavefront's momentum (the Poynting vector) is the same as the photon's momentum. This means that you have a deflection effect. This means we expect to see blurring. Case closed.
If you wish to reopen the case, JK, please respond to Zathras' force criticism and the wavelength dependence of the redshift. As far as I'm concerned you've proven yourself incapable of supporting your pet mechanism.
Established Member
Nonsense, this is a horrible model it doesn't do what it proports to do in the least. Reverse engineering at its worst... and let's sees a GP effect out of this! (HINT: there is none).
And a model introducing an Intrinsic Redshift of Z 3 explaining the Layman Alpha Forest
http://216.239.53.100/search?q=cache...hl=en&ie=UTF-8
Convenient and impossible theorizing. Herein is the problem, if you want a uniform "cloak" at z=3 you have to see the stuff in emission. It is not seen. Therefore I dismiss your theory as hogwash.*If these ideas are correct, a truly inter- and pro-
togalactic medium at high redshift Z 3*
the main repository of baryons
collapses under the influence of dark matter gravity into flattened or filamentary
structures, which are seen in absorption against background QSOs. With decreas-
ing redshift, galaxies forming in the denser regions may contribute an increasing
part of the Ly
absorption cross section.
Banned
Did you read all the study before reaching your conclusions.This is a very detailed model made by the very serious Arizona Edu U niversity of course this is not in accord with your conception of the Universe, so who we will believe?You seem in complete disagreement with the conclusion of other Big Bang -modelers-!On 2003-01-27 17:08, JS Princeton wrote:
Nonsense, this is a horrible model it doesn't do what it proports to do in the least. Reverse engineering at its worst... and let's sees a GP effect out of this! (HINT: there is none).
And a model introducing an Intrinsic Redshift of Z 3 explaining the Layman Alpha Forest
http://216.239.53.100/search?q=cache...hl=en&ie=UTF-8
Convenient and impossible theorizing. Herein is the problem, if you want a uniform "cloak" at z=3 you have to see the stuff in emission. It is not seen. Therefore I dismiss your theory as hogwash.*If these ideas are correct, a truly inter- and pro-
togalactic medium at high redshift Z 3*
the main repository of baryons
collapses under the influence of dark matter gravity into flattened or filamentary
structures, which are seen in absorption against background QSOs. With decreas-
ing redshift, galaxies forming in the denser regions may contribute an increasing
part of the Ly
absorption cross section.
http://216.239.53.100/search?q=cache...hl=en&ie=UTF-8
Established Member
Orion, don't you understand that this paper is in support NOT of alternative models but in support of the mainstream?
Banned
I think this paper support Marmet`s theory indirectly.Even if it was done by the mainstream.On 2003-01-27 18:23, JS Princeton wrote:
Orion, don't you understand that this paper is in support NOT of alternative models but in support of the mainstream?
Marmet A New Non-Doppler Redshift
http://www.newtonphysics.on.ca/HUBBLE/Hubble.html
What makes you change your mind about this paper
http://216.239.53.100/search?q=cache...hl=en&ie=UTF-8
You wrote Posted: 2003-01-27 17:08
Nonsense, this is a horrible model it doesn't do what it proports to do in the least. Reverse engineering at its worst... and let's sees a GP effect out of this! (HINT: there is none).
--
Convenient and impossible theorizing. Herein is the problem, if you want a uniform "cloak" at z=3 you have to see the stuff in emission. It is not seen. Therefore I dismiss your theory as hogwash.
<font size=-1>[ This Message was edited by: Orion38 on 2003-01-27 19:46 ]</font>
Established Member
Orion, the paper is about observational evidences and models that tie in reionization with the lyman alpha forest. What I was criticizing was Marmet's nonsense (and it really is just that). You need to learn a bit more if you think that there is a comparison between these two models. The paper you cite is from CalTech by people who buy a Lambda-CDM model being the best parametrization of our universe. Their tweaking with alternatives makes them conclude that they can fit a decent model for the Ly-alpha forest. Marmet's nonsense is just baloney. We've gone through it before, Orion, and you're basically wasting our time
Banned
The study talk about the interaction of gas cloud causing the Layman Alpha Forest and is in direct line of thought with Marmet worksOn 2003-01-27 20:46, JS Princeton wrote:
Orion, the paper is about observational evidences and models that tie in reionization with the lyman alpha forest. What I was criticizing was Marmet's nonsense (and it really is just that). You need to learn a bit more if you think that there is a comparison between these two models. The paper you cite is from CalTech by people who buy a Lambda-CDM model being the best parametrization of our universe. Their tweaking with alternatives makes them conclude that they can fit a decent model for the Ly-alpha forest. Marmet's nonsense is just baloney. We've gone through it before, Orion, and you're basically wasting our time
about a Non Doppler Redshift
http://www.newtonphysics.on.ca/BIGBANG/Bigbang.html
http://www.newtonphysics.on.ca/hydrogen/index.html
A Canadian Astrophysicist presents this evidence and explains how the cosmic redshift is caused by gaseous matter in space, not by the Doppler effect.
Caption for Crab Nebula.
Interstellar matter, seen here in the Crab Nebula in Taurus, has its counterpart on a larger scale in the rarefied intergalactic medium. The intergalactic medium was first shown to exist in the 1970s. It is impossible, the author says, for the light we see from distant galaxies not to interact with this medium as it passes through it.
Established Member
I have had some correspondence with Jacques Moret-Bailly of the Laboratory de Physique, U. of Bourgogne, 2100 Dijon France. He is a strong proponent of Raman scattering causing the red shift. He sent me a paper called "A tentative elementary model of quasars" that uses this mechanism. I think some of his papers are posted on the internet on the university website. I think this may partially cut the mustard.(Dijon pun intended). However, I don't think this would operate over the entire spectrum like the Compton effect or produce the background hectometric radiation for the cosmological interpretation, but he may disagree.On 2003-01-27 15:23, Laser Jock wrote:
I believe that would be equivalent to Raman scattering. I can see two problems with trying to explain redshifts with this. First, the direction that the light is re-emitted will not likely be in the same direction as the original direction so an object would still be blurred. Second, the resulting spectrum would be very different than the original object. We would see nothing like the spectral lines of hydrogen (redshifted or not).On 2003-01-27 15:03, cable wrote:
how about light traversing a medium that absorbs light then reemits it at a lower frequency ??
in this case we have redshift with no Doppler or Compton .
Established Member
The paper you reference is dealing with the scattering from targets that have bound or loosley bound electrons in the atom or molecule. It has to do with things like the Klein-Nishina formula which involves the energy loss necessary to get the electon out of the bounds to the target atom and release it so that it is a free electron. The energy needed to free the electron from the atom depends on the charge state of the electron and has nothing to do with basic mechanism of the Compton effect. There are crosssections related to this, but that is different from the basic cross section of an already free electron. That's why their cross section has to do with the charge state of the target. There is much confusion about cross-sections which are used to calculate the probability of a collision. There will be no wavelength change collision with an electron if the incoming photon does not have enough energy to ionize the target. So, if there is no collision the crossection is zero. This has nothing to do with the calculation of the probability of collision with an already free electron that is not bound to anything. The Klein-Nishina formula reduces to the Thomson cross-section for an already free electron, even though the Thomson mechanism was shown by Compton to be incorrect.On 2003-01-27 15:37, Zathras wrote:
John, the paper cited below deals with this point:On 2003-01-27 15:28, John Kierein wrote:
. . .
There are attempts to marry the Thomson scattering with Compton scattering, but the data do not support this only theoretical attempt. Thomson scattering was thought to be the mechanism for interaction of electrons with electromagnetic waves on a theoretical basis. This mechanism was that the wave was composed of varying electric and magnetic fields. The theory is similar to that of an antenna picking up a signal by having conductive electrons in a wire respond to the varying electric field of the wave and thus generate a current of the same signal. The theory is that the electron responds to the incoming varying electric field and vibrates up and down at the same frequency as the incoming wave, thus generating a new isotropic wave and causing blurring. This theory is not correct according to Compton. This theory predicts the scattering to be isotropic from the scatterer and definitely will not work for scattering from neutral particles. It does not predict a change in wavelength, although there have been attempts to modify the theory to make this work by classical physicists.
On the other hand, the Compton effect has nothing to do with the charge of the electron or the varying electric field of the photon. It is entirely described by billiard ball mechanics and gives the resulting acceleration of the electron to a new velocity with a new kinetic energy and a corresponding loss of energy of the photon to a shorter wavelength. It correctly predicts the change in wavelength of the photon and the energy of the electron. It also occurs for scattering from neutral particles unlike the previously wrong description of the Thomson scattering as being the mechanism, which is still taught in schools despite this.
. . .
http://www.phys.ksu.edu/~cdlin/articles/cdl/j104.pdf
This paper shows that Compton scattering in fact does depend on the charge state, so that there is more than just the billiard ball dynamics.
The next question I would have for you is this: if Compton scattering is not based on E&M, what force is it based on? This is multiple choice: has to be either (a) strong nuclear force; (b) weak nuclear force; (c) gravity; or (d)E&M. It's obviously not the strong force (e-'s do not interact this way) or gravity. What does that leave you?
<font size=-1>[ This Message was edited by: Zathras on 2003-01-27 15:41 ]</font>
The Compton effect is exactly explained by exchanges of energy and momentum exactly like a billiard ball. These are momentum exchanges and the forces involved are exactly the same as billiard balls. Billiard ball dynamics are none of the forces you describe, but are just the equations of motion and the conservation of energy and momentum. The electromagnetic energy of the photon is converted to kinetic energy of the electron very elegantly and straightforwardly. You may enjoy going to Compton's lengthy 1923 paper see the entire setup of his experiments and his derivations as well as his attribution of the solar red shift to the Compton effect. (Compton, A. H., 1923 Phil. Mag. 46, 897.) I almost fell off my chair when I read that! The old masters knew their stuff!
<font size=-1>[ This Message was edited by: John Kierein on 2003-01-27 23:24 ]</font>
Established Member
Orion, you are seriously misguided if you think that Lyman Alpha Forests are caused by redshifts in the mainstream model. They are caused by line of sight absorptions and, in fact, emissions.
Established Member
Ta da! We finally have the crankiest statement to come out. Completely non-physical. Billiard balls repel each other because of one of two reasons: one is degeneracy pressure due to the Pauli-exclusion principle (which is a direct result of the strong nuclear force in one way of looking at it) or as a result of the electromagnetic force. Not realizing that there are four fundamental forces which it ultimately breaks down to is a showing of JK's lack of knowledge and understanding (and frankly refusal to understand) in this area.On 2003-01-27 23:16, John Kierein wrote:
The Compton effect is exactly explained by exchanges of energy and momentum exactly like a billiard ball. These are momentum exchanges and the forces involved are exactly the same as billiard balls. Billiard ball dynamics are none of the forces you describe, but are just the equations of motion and the conservation of energy and momentum.
Still waiting on the wavelength dependence. Notice that JK can't deal with simple discussions of the dynamics of these interactions which are seen in the laboratory and instead tends to veer off in directions of incomprehensibility. If anybody doesn't understand the mechanism for redshifts from the mainstream it is available for explanation. If anybody doesn't understand JK's explanations, well, they're in good company.
Yes, it is a crackpot idea.
Of course, Compton agreed that the effect was due to electromagnetism as do the rest of the sane in this thread. You can actually read about it in the very article that JK cites. Feynman actually sums it up best in his book QED (for the layman) where he states that all interactions between photons and electrons are electromagnetic in nature. They involve exchanges of photons. Yes, photons can exchange photons with each other and photons can exchange photons with neutrons (though the cross-sections are small). These are ALL electromagnetic interactions. In fact, the ONLY way that particles interact microscopically is through the exchange of a force-carrier boson. End of story.The electromagnetic energy of the photon is converted to kinetic energy of the electron very elegantly and straightforwardly.
Notice also, gentle reader, that JK has yet to admit to reading the paper that started this thread. Will he read it? Doubtful.
Established Member
Check the parenthetical I made about Pauli exclusion and the nuclear force. I was thinking too much about degenerate stars recently. Of course, with electrons, the Pauli exclusion principle ONLY involves photons as the boson interactions. We therefore have electromagnetism as the reason for billiard balls interacting all around.
I will point out that billiard balls are NEVER EXACTLY the right way to look at a problem in detail. This is because no collision can ever be completely elastic which is what billiard balls are meant to convey. In fact, in quantum mechanics and with Compton scattering the correct way to look at the problem is to solve Schrodinger's Equation. It's actually something that is done in most introductory QM texts rather elementarily and to get the quoted result we've been dealing with.
Of course, we still have redshift dependent on wavelength. Remember, this is something that isn't observed and JK has offered no explanation. The sound of silence.
Established Member
Hey, I answered that for you here. You Obviously didn't read it. Hello neighbors, hello friends.
Of course, we still have redshift dependent on wavelength. Remember, this is something that isn't observed and JK has offered no explanation. The sound of silence.
http://www.geocities.com/CapeCanaver...5/compton.html
(By the way I've met Assis a couple of times. A nice guy from U. Campanos Brazil. The last time I met him (@ a conference @ the U. of Ct) he sorta apologized for this paper after seeing the above, but he's never retracted it. I like his history of the 3 deg K paper. I attempted to rebut this paper, but they quit publishing the journal.)
<font size=-1>[ This Message was edited by: John Kierein on 2003-01-28 17:25 ]</font>
<font size=-1>[ This Message was edited by: John Kierein on 2003-01-28 17:29 ]</font>
Established Member
Uhh... sorry... no dice. You gotta look at the paper I cited, JK. You have not answered the fundamental problem with your idea that is brought up.
Established Member
I can't see any physical sense in the idea that the Compton effect could cause what we refer to as the cosmological redshift.
Compton scattering does not happen at all for photons with an energy much below the rest energy of the electron (511 kev) in the rest frame of the electron. That means the electron has to see a photon that has a wavelength not much larger than 0.024Å. Contrast this with the wavelength & energy of a Lyman-alpha photon (1216Å, 10.2 ev). Lyman-alpha is far too low in energy to Compton scatter under any but perhaps extraordinary circumstances.
Lyman-alpha photons are commonly used to determine cosmological redshifts, as are numerous lower-energy spectral features. Yet simple physical considerations show that these photons should be essentially immune to Compton scattering. This implies that the cosmological redshifts are not caused by the Compton effect.
The scattering cross sections & probabilites for Compton scattering are far below those for Thomson scattering (see, for instance, figure 14.18 in the 3rd edition of Jackson's Classical Electrodynamics). So, considering both the low photon energy, and the much smaller Compton scattering probability, one would expect the process to be dominated by Thomson scattering in any case.
The strong energy dependence of Compton scattering means that it is incapable of producing a wavelength independent redshift. On the other hand, an expanding universe should produce a wavelength independent redshift. The observed cosmological redshift is wavelength independent, which favors an expanding universe origin over a Compton effect origin.
These two arguments look strong to me. Photons short of X-ray wavelengths are too low in energy to experience any significant Compton scattering, and Compton scattering cannot produce a wavelength independent redshift.
Established Member
Tim: Where did you get the idea that photons with less energy than the rest energy of an electron don't scatter from electrons? True, the Compton effect is normally seen in the lab for high energy photons, but that's because they must be more energetic than the binding energy to the target atom in order to release the electron from the atom. But for an already free electron the photon doesn't ignore the electron no matter what the photon energy. Sure the change in wavelength per interaction as a percentage of the photon's original energy is very small for long wavelengths, but it's there. Compton himself said the red shift on the sun was Compton and this is for visible wavelengths.
The Klein-Nishina formula gives the cross section for a target atom and it reduces to the Thomson cross section for a free electron.
Look at this which I gave in another thread: http://www.geocities.com/CapeCanaver...5/compton.html
<font size=-1>[ This Message was edited by: John Kierein on 2003-01-29 20:49 ]</font>
<font size=-1>[ This Message was edited by: John Kierein on 2003-01-29 20:54 ]</font>
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JK: Where did you get the idea that photons with less energy than the rest energy of an electron don't scatter from electrons?
From Classical Electrodynamics, J.D. Jackson, John Wiley & Sons, 3rd edition, 1999. See section 14.8, pp.694-697.
Quote: "The classical Thomson formula is valid only at low frequencies where the momentum of the incident photon can be ignored. When the photon's momentum hbar*omega/c becomes comparable to or larger than mc, modifications occur. These can be called quantum mechanical effects, since the concept of photons as massless particles with momentum and energy is certainly quantum mechanical (pace, Newton!), but granting that, most of the modifications are purely kinematical. The most important change is the one observed experimentally by Compton. The energy or momentum of the scattered photon is les than the incident energy because the charged particle recoils during the collision." (pp. 695-696).
The same discussion occurs in section 14.7 of the 2nd edition, which I have from my student days and is probably more common on bookshelves.
From Radiative Processes in Astrophysics, G.B. Rybicki & A.P. Lightman, John Wiley & sons, 1979. See chapter 7, p.195, "Compton Scattering".
Quote: "For low photon energies, h*nu very much less than mc^2, the scattering of radiation from free charges reduces to the classical Thomson scattering, discussed in chapter 4." The authors go on to develop the theory of Compton scattering & inverse Compton scattering in great detail.
JK: The Klein-Nishina formula gives the cross section and it reduces to the Thomson cross section for a free electron.
Correct. However, in the Klein-Nishina formula, the cross section is energy dependent. Compton scattering becomes less efficient at higher energies (see Rybicki & Lightman, p. 197). This in turn means that the optical depth for Compton scattering is also energy dependent. That's why the Compton effect cannot produce a wavelength-independent redshift, because the scattering optical depth is wavelength (energy) dependent.
It may not be exactly correct to say that Compton scattering does not occur at all for low energy photons, but it is correct to say that the scattering optical depth will drop so close to zero that Compton scattering ceases to be a physically significant process at such low photon energies. Compton himself discovered the effect with X-rays, where photon energies are high enough to make the process work.
<font size=-1>[ This Message was edited by: Tim Thompson on 2003-01-29 21:26 ]</font>
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Isn`it this aspect than Marmet resolve when he introduce the bremsstrahlung in his calculations?On 2003-01-29 20:40, Tim Thompson wrote:
Compton scattering does not happen at all for photons with an energy much below the rest energy of the electron (511 kev) in the rest frame of the electron. That means the electron has to see a photon that has a wavelength not much larger than 0.024Å. Contrast this with the wavelength & energy of a Lyman-alpha photon (1216Å, 10.2 ev). Lyman-alpha is far too low in energy to Compton scatter under any but perhaps extraordinary circumstances.
Lyman-alpha photons are commonly used to determine cosmological redshifts, as are numerous lower-energy spectral features.
http://www.newtonphysics.on.ca/HUBBLE/Hubble.html
In this paper, we consider this problem at very low energy (visible light and lower energy) where classical considerations are still mostly valid. We consider further the case of photon scattering on atoms at an extremely low atom density, which is a condition prevailing in outer space. In the usual treatment of the Compton effect, bremsstrahlung is neglected. In these circumstances, it is known that the change Dl in wavelength is given by:
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