- #1
artis
- 1,481
- 976
So as the hot plasma of a universe expanded it grew colder and at "recombination" it reached a state where it isn't opaque to em radiation any more unlike dense plasma which is.
So we say this is the moment the CMB started.
But this got me thinking, after recombination the matter was still some 3000 K hot and I would assume it did not cool momentarily but it was a gradual process. The universe still being much smaller than today and rather dense , why don't we see a range of frequencies as the CMB?
In other words the matter after recombination was still giving off radiation for some time (and continues to this day) so shouldn't there be a wide range of frequencies seen as the CMB?
Say for example the radiation given off after recombination was of ever lower frequency adding redshift due to expansion it could now be in the Mhz range and some maybe even lower?
So we say this is the moment the CMB started.
But this got me thinking, after recombination the matter was still some 3000 K hot and I would assume it did not cool momentarily but it was a gradual process. The universe still being much smaller than today and rather dense , why don't we see a range of frequencies as the CMB?
In other words the matter after recombination was still giving off radiation for some time (and continues to this day) so shouldn't there be a wide range of frequencies seen as the CMB?
Say for example the radiation given off after recombination was of ever lower frequency adding redshift due to expansion it could now be in the Mhz range and some maybe even lower?