Cosmological theories of special and general relativity - II

Astronomers measure distances to faraway galaxies and their velocities. They do that in order to determine the expansion rate of the Universe. In Part I of these lectures the foundations of the theory of the expansion of the Universe was given. In this part we present the theory. A formula for the distance of the galaxy in terms of its velocity is given. It is very simple: r(v) = c tau/beta sinh beta nu/c, where tau is the Big Bang time, beta = root 1 - Omega(m), and Omega(m) is the mass density of the Universe. For Omega(m) < 1 this formula clearly indicates that the Universe is expanding with acceleration, as experiments clearly show.