Exposé du point de vue “conventionnel” sur les décalages vers le rouge.

In Peebles’ well-known textbook, one chapter is entitled “a child’s garden of cosmological models”. Maybe a “jungle” would better describe the lush diversity of theories expounded at this exceptionally interesting conference. If there is a dominant orthodoxy in cosmology, the proceedings here have successfully obscured it – a participant without prior exposure to the subject would not have gleaned from this week’s discussions what views were “conventional” and what were not. Anyway, I presume that my brief is to assess the status of the cosmological views that would commend themselves to Peebles and his like: that is to say, the package of ideas in which there was a “hot big bang”, galaxies and clusters condensed via gravitational instability, the quasar phenomenon is related to galactic nuclei, and all large redshifts (except perhaps quasar absorption lines) are due to the expansion of the universe. This, at least, is the framework within which we “conventional” people attempt to interpret the data – or (in the view of some “radicals”) the self-imposed blinkers by which our vision is confined.