Publication : t04/156

Abstract:
The full recognition of the genuine expansion of the Universe and all its consequences is what led to the construction of the 'hot big-bang' scenario. The reasons why it is now widely accepted as the standard model of cosmology are reviewed. They are all related to the fact that, if matter and energy is to be conserved is an expanding Universe, its content gets diluted over cosmological time implying that it has experienced a thermal history. Many physical phenomena associated with this evolution have been identified, the signatures of which have been actively looked for and indeed been found in a series of crucial observations, from big-bang nucleosynthesis to the patterns expected from the gravitational growth of structure of the Universe. What is well established, what is speculative and the questions that are totally left unanswered in the standard cosmology scenario is succinctly presented.

publi.pdf