Facts — Observations of Cosmological Significance

Abstract

In this chapter various observations relevant to cosmology will be introduced. We shall see how they fit into a “standard model” — one of the homogeneous, isotropic Friedmann—Lemaître models presented in the last chapter — and to what extent they determine the parameters. In Chap. 1 we pointed out that the cosmological model and the present epoch (t ₀) can be determined by the measurement of two dimensionless numbers: q ₀, ${{q}_{0}},{{\Omega }_{0}} \equiv {{\varrho }_{0}}/\varrho C$, and a scale constant H ₀ . Λ = 0 is equivalent to 2q ₀ = Ω₀.

“There are probably few features of theoretical cosmology that could not be completely upset and rendered useless by new observational discoveries.”

H. Bondi

“I hate reality, but it is still the only place where I can get a decent steak.”

Woody Allen