Let me say again that the abandonment of this one particular model in no way represented a rejection of the big bang. For details on the solidity of the evidence supporting it, evidence that has been convincing through the past twenty-five years, you may wish to see the ninth chapter of my book, The Fingerprint of God , second edition. The book also explains why the big bang has opponents. Some Christians have been bothered by that age figure, mistakenly believing that it contradicts the teaching of the Bible about when God created. The new COBE discovery is not so much a proof of the big bang theory, as some popular news reporters have indicated, as it is a significant step closer to an accurate big bang model.
Exotic matter is stuff that weakly interacts with radiation.
Since this kind of matter can act relatively independently of radiation, it is possible for this exotic matter to clump while the radiation remains nearly smooth. Then, through the action of gravity, the exotic matter could attract ordinary matter to it. In a universe containing much more exotic matter than ordinary matter, the background radiation could be relatively smooth while the galaxies are clumpy. Die hard opponents to the big bang were hoping that even this tiny level of unevenness in the background radiation never would be seen. But, all their forlorn hopes were dashed on April 24.