WAS THERE REALLY A BIG BANG?

The big-bang cosmology described in the last two chapters has a large following amongst the astronomical community. The models of Friedmann are able to account for the observed expansion of the Universe, for the smooth background of microwave radiation, and for the abundance of light nuclei that cannot be generated inside stars. Are these not good enough reasons for believing in the overall picture?

Playing the devil's advocate in this chapter, let me voice a few dissenting views. First, a scientific theory, howsoever successful it may be, must always be vulnerable to checks of facts and conceptual consistency. Even a well established theory like Newton's had to give way to Einstein's when it was found wanting under these checks (see Chapter 5). The formidable facade of big-bang cosmology is likewise developing cracks that can no longer be plastered over.

The first crack has actually been there right from the beginning and may have been noticed by the reader of Chapter 9. He or she may ask the questions, ‘What preceeded the big bang? How did the matter and radiation in the Universe originate in the first place? Does it not contradict the law of conservation of matter and energy?’

These questions cannot be answered within the framework of Einstein's general theory of relativity, which was used to construct the Friedmann models. The moment of ‘big bang’ is a singular epoch, according to the theory, just as the end of a collapsing object, described in Chapter 7, is in a singularity.