Cold big-bang cosmology as a counterexample to several anthropic arguments- art. no. 083508

A general Friedmann big-bang cosmology can be specified by fixing a half-do zen cosmological parameters such as the photon-to-baryon ratio eta (gamma), the cosmological constant Lambda, the curvature scale R, and the amplitude Q of (assumed scale-invariant) primordial density fluctuations. There is c urrently no established theory as to why these parameters take the particul ar values we deduce from observations. This has led to proposed "anthropic" explanations for the observed value of each parameter as the only value ca pable of generating a universe that can host intelligent life. In this pape r, I explicitly show that the requirement that the universe generates Sun-l ike stars with planets does not fix these parameters, by developing a class of cosmologies (based on the classical "cold big-bang" model) in which som e or all of the cosmological parameters differ by orders of magnitude from the values they assume in the standard hot big-bang cosmology, without prec luding in any obvious way the existence of intelligent life. I also give a careful discussion of the structure and context of anthropic arguments in c osmology, and point out some implications of the cold big-bang model's exis tence for anthropic arguments concerning specific parameters.