Limits on a microwave background without the big bang

Abstract

The possibility of explaining the cosmic microwave back- ground in terms of thermalisation of radiation from such sources as galaxies by dust grains is explored further. Relevant calcula- tions of the optical cross-sections of graphite whiskers are given and it is shown that a smeared out dust density of ^ 10~³³ g cm~³ is required. Limits are set on the large-angle anisotropy of the background which is to be expected on the basis of this model. The relative merits of the conventional explanation and the present theory are discussed and a few discriminatory observational tests proposed. Some cosmological implications of whisker grains in the intergalactic space are examined.