The conclusive evidence that the universe began in a fiery ball of radiation, some 13.8 billion years ago, came from the discovery of what the Russians have called 'relic' radiation even before it was discovered! And even when it was discovered, presumably by Penzias and Wilson, it was at a single frequency of 4 GHz. So since when does a single frequency determine a black body spectrum?
Penzias and Wilson measured a total temperature of 6.7 degrees Kelvin. They attributed 2.3 of that to the atmosphere, 0.8 to Ohmic losses and a back lobe response to the ground of 0.1. That left a whopping 3.5 degrees to some unknown radiation. Just a few miles from where they made their discovery at Holmdel NJ, Dicke and Peebles were working on Gamow's conjecture of a hot big bang as the birth of the universe whose relic radiation would be about 5 degrees Kelvin. Without a moment of hesitation, they dubbed this the remanence of the big bang, a term coined by Fred Hoyle in mocary of the proposal.
Immediately they went to publish their findings--but with the cart before the horse. The Dicke and Peebles paper preceded that of Penzias and Wilson who had initially no knowledge of what they measured. Never before in the history of science had the interpretation preceded the discovery! But, this seems to be a pattern. The LIGO team had the spectra in-hand of what they wanted to observe! So history repeats itself, and so do the mistakes!
It wasn't until the launch of the COBE and Planck satellites that the unsymmetrical bell-shaped curve characteristic of black body radiation was supposedly mapped out--and at the precise temperature reported by Penzias and Wilson. However, a more recent optical radio telescope was constructed by Paris Herouni in Armenia in the former Soviet Union. This telescope guarded against the diffraction of stray signals into the antenna, unlike that of Penzias and Wilson, and measured only a temperature of 2.6 K. Taking all other contributions into account that left nothing for the microwave background radiation which they were supposed to find at an 8 mm wavelength. What happened?
The supposedly 6 degree Kelvin was nowhere to be found. After hesitating over a decade, Herouni published his finding in an out of the way Greek journal. If that wasn't enough, the paper seeming disappeared. Such is the shenanigans of the cosmological community "where personal beliefs and personal prejudice enter strongly into cosmology" to quote Hoyle, Burbidge and Narlikar in their Different Approach to Cosmology.
We won't even question what consists the opaque enclosure necessary to obtain black body radiation. But once accepting a black body spectrum that the COBE satellite measured out to centimeter wavelengths, the million dollar question became where did all the structure we observe in the universe come from? The fact that a precise black body spectrum was observed should have been sufficient to exclude any macroscopic excursion from thermal equilibrium. It would be equivalent to observing a melted ice cube reforming in a glass of whiskey. Sure fluctuations exist, but not those that could be the culprit of the formation of stars and galaxies. And here the fun and games begin.
There is a small dipole anisotropy of about 0.0033 degrees associated with the motion of the Milky Way through the microwave background. Anisotropies in the radiation field smaller than that, although extremely difficult to measure, must be found for without them there would be no galaxies and no us. But look at the ludicrous path of events: We wait more than an infinite amount of time (certainly the time given by the standard model of 380 000 years is too small) so as to secure a final resting place of thermal equilibrium and then we look for needles in the haystack to take us out of that resting state! This defies all logic, but has been engraved into the standard model.
Penzias and Wilson found their radiation to be isotropic to within 10%. The big bangers reasoned that fluctuations in density caused by gravitation should amount to between 0.1 and 1% to get galaxies to form. When such anisotropies, or temperature fluctuations, were not found, they didn't throw the towel in but, rather, went to the next level. They certainly should be recommended in their perserverance in the face of defeat, and now claimed that the relative thermal fluctuation should be of the order of 0.00001. This was confounded by the so-called inflationary model which predicted that the universe was virtually at its critical value. Another of order of magnitude lower could be achieved if the universe was dominated by non-baryonic matter. The idea of non-baryonic matter was supposedly to guarantee that the formation of the light elements occurred in the big bang, and the seemingly low level of temperature perturbations.
Pushed to the limit, with their backs to the wall, the big bangers finally could claim that temperature fluctuations were found by COBE at a temperature difference of some 30 microkelvin at a large angular scale of some 10 degrees. These fluctuations were attributed to density variations on a scale of not greater than 100 Mpc as seen today. This led Smoot to claim that "if you are a religious person, it's like seeing the face of God", and Turner to burst out with "They have found the Holy Grail of Cosmology," The scientists are no worse than the people who believe them.
The bottom line is: You don't go to equilibrium to get nonequilibrium structures. Those structures must have formed prior to the bodies that emit a thermal, black body spectrum. And the opposite is also true. According to the big bangers, any matter present would destroy the background radiation by causing hot spots leading to thermal fluctuations of at least a thousand times greater than those actually observed. This is a classic example of which came first, the chicken or the egg.