ABSTRACT
Cosmology is, simply put, the study of the universe. Relativistic cosmology
is the study of solutions of Einstein’s equation, which may represent the
broad features of the universe as a whole.
One constraint on such models is the seemingly innocuous statement
that the sky is dark at night. Why is this surprising? In a Euclidean
universe with a uniform distribution of stars, both the density of matter
and the apparent luminosity fall off as 1/r2. Thus, the perceived brightness
of every thin spherical shell of stars, as seen at the center of the sphere, is
the same; an infinite universe would therefore lead to an infinitely bright
night sky! This seeming contradiction is known as Olbers’ paradox.
