CMBR

[Alan Grayson]

I've asked this before but can't recall the responses, so bear with me. At the time of recombination, when H atoms formed, is the CMBR the result of the fact that the total energy of neutral H is LESS  than that of protons and electrons existing independently, and that the CMBR is the energy emitted when H atoms formed? If not, what is the source of the CMBR? TIA, AG

[Alan Grayson]

On Wednesday, April 8, 2020 at 7:52:19 PM UTC-6, Alan Grayson wrote:

I've asked this before but can't recall the responses, so bear with me. At the time of recombination, when H atoms formed, is the CMBR the result of the fact that the total energy of neutral H is LESS  than that of protons and electrons existing independently, and that the CMBR is the energy emitted when H atoms formed? If not, what is the source of the CMBR? TIA, AG

I think that was my original hypothesis, which is apparently incorrect as it would result in a single emission frequency, not that of a blackbody. AG  

[Alan Grayson]

On Wednesday, April 8, 2020 at 8:01:40 PM UTC-6, Alan Grayson wrote:

On Wednesday, April 8, 2020 at 7:52:19 PM UTC-6, Alan Grayson wrote:

I've asked this before but can't recall the responses, so bear with me. At the time of recombination, when H atoms formed, is the CMBR the result of the fact that the total energy of neutral H is LESS  than that of protons and electrons existing independently, and that the CMBR is the energy emitted when H atoms formed? If not, what is the source of the CMBR? TIA, AG

I think that was my original hypothesis, which is apparently incorrect as it would result in a single emission frequency, not that of a black-body. AG  

The confusion, IMO, of what it means to be a "black-body" involves the idea that "black" generally means total absorption of incoming radiation, implying no emission, whereas the usual example of black-body radiation is the emission from a small hole in a cavity which is at thermodynamic equilibrium.  What seems to be the case, is that incoming radiation in the cavity example is totally absorbed -- no reflection whatsoever -- but the incoming photons are bounced around the walls of the cavity, possibly changing frequency with each impact, with the emitted radiation taking the form of the distribution of so-called black-body radiation. This connects with the idea that the CMBR is predicted to a black body distribution since before recombination, photons were entrapped in the early, foggy universe as if they were in a cavity. AG