Interpretation of the cosmic microwave background

Abstract

The discovery of microwave background radiation by Penzias and Wilson is one of the most interesting events in observational astronomy in recent years. On the basis of the first observations at a single wavelength, the radiation was interpreted as being of the black-body type, and it was concluded that this was the remnant of the primordial radiation of a big-bang universe. Later results by different observers have strengthened this interpretation. Indeed it is now claimed that the black-body curve applies for a wavelength range of 1:90, and corresponds to a temperature T=2.68° K. The observers go as far as to state that the exact black-body intensity curve I(ν) ∝ ν³/e^hν/kT−1 (1) fits the observations better than the "grey-body" approximation at long wavelengths-namely I(ν) ∝ ν² (2).