The microwave “background”

2. The microwave “background” makes more sense as
the limiting temperature of space heated by starlight
than as the remnant of a fireball.
The expression “the temperature of space” is the title of chapter 13 of
Sir Arthur Eddington’s famous 1926 work. [4] Eddington calculated
the minimum temperature any body in space would cool to, given that

it is immersed in the radiation of distant starlight. With no adjustable
parameters, he obtained 3 K (later refined to 2.8 K [5]), essentially the
same as the observed, so-called “background,” temperature. A similar
calculation, although with less certain accuracy, applies to the limiting
temperature of intergalactic space because of the radiation of galaxy
light. [6] So the intergalactic matter is like a “fog,” and would
therefore provide a simpler explanation for the microwave radiation,
including its blackbody-shaped spectrum.
Such a fog also explains the otherwise troublesome ratio of
infrared to radio intensities of radio galaxies. [7] The amount of
radiation emitted by distant galaxies falls with increasing
wavelengths, as expected if the longer wavelengths are scattered by
the intergalactic medium. For example, the brightness ratio of radio
galaxies at infrared and radio wavelengths changes with distance in a
way which implies absorption. Basically, this means that the longer
wavelengths are more easily absorbed by material between the
galaxies. But then the microwave radiation (between the two
wavelengths) should be absorbed by that medium too, and has no
chance to reach us from such great distances, or to remain perfectly
uniform while doing so. It must instead result from the radiation of
microwaves from the intergalactic medium. This argument alone
implies that the microwaves could not be coming directly to us from a
distance beyond all the gala xies, and therefore that the Big Bang
theory cannot be correct.

None of the predictions of the background temperature based on
the Big Bang were close enough to qualify as successes, the worst
being Gamow’s upward-revised estimate of 50 K made in 1961, just
two years before the actual discovery. Clearly, without a realistic
quantitative prediction, the Big Bang’s hypothetical “fireball”
becomes indistinguishable from the natural minimum temperature of
all cold matter in space. But none of the predictions, which ranged

between 5 K and 50 K, matched observations. [8] And the Big Bang
offers no explanation for the kind of intensity variations with
wavelength seen in radio galaxies.