Willem de Sitter

"Is the density anywhere near that corresponding to the static universe, or is it so small that we can consider the empty universe as a good approximation?"

"Gravitation is entirely independent of everything that influences other natural phenomena. It is not subject to absorption or refraction, no velocity of propagation has been observed. You can do whate…"

"Theories Of The Universe by Munitz,Milton K. includes "Relativity and Modern Theories of the Universe"

"Since we only consider the universe on a very large scale, and make abstraction of all details and local irregularities, our universe must be homogeneous and isotropic. It follows... that the three-di…"

"We know by actual observation only a comparatively small part of the whole universe. I will call this "our neighborhood." Even within the confines of this province our knowledge decreases very rapidly…"

"In the beginning of 1917, two solutions of the field equations for a homogeneous isotropic universe had been found, which I... call the solutions "A" and "B." ...at that time only static solutions wer…"

"Gravitation is not only similar to inertia in its generality, it is also measured by the same number... the mass. The inertial mass is what Newton calls the "quantity of matter": it is a measure for t…"

"It is possible to relegate the epoch of the starting of the expansion to minus infinity, e.g. by using instead of the ordinary time the logarithm of the time elapsed since the beginning. But this is o…"