Final answer:
Black body radiation provides evidence of the Big Bang theory, having properties that are consistent with the universe's cooling over billions of years since the Big Bang, and is aligned with the discovery of the cosmic microwave background radiation by Arno Penzias and Robert Wilson.
Step-by-step explanation:
Black body radiation provides evidence of the Big Bang theory. Essentially, it is considered to be a remnant of the primordial fireball that would have existed if the Big Bang had occurred. The characteristics of the radiation suggest it has been traveling through space since shortly after the Big Bang, becoming redshifted over time, which implies a cooling process. The temperatures associated with the blackbody radiation are orders of magnitude lower than would be expected immediately after the Big Bang.
The concept of a blackbody, an idealized perfect absorber and emitter of thermal radiation, is fundamental in understanding how objects at a thermal equilibrium radiate energy. Only energy in discrete quanta is exchanged, as proposed by Max Planck, contradicting classical continuous exchange theories and paving the way for the development of quantum physics.
After their predictions in the 1940s, George Gamow and collaborators provided estimates for the temperature of this cosmic blackbody radiation, which should be approximately 7 Kelvin, peaking at microwave frequencies. Verification came in 1964 when Arno Penzias and Robert Wilson detected this cosmic microwave background radiation, confirming the predictions and the Big Bang model.