Editing Arthur Eddington (section)

==Cosmology==
Eddington was also heavily involved with the development of the first generation of general relativistic cosmological models. He had been investigating the instability of the Einstein universe when he learned of both [[Georges Lemaître|Lemaître's]] 1927 paper postulating an expanding or contracting universe and Hubble's work on the recession of the spiral nebulae. He felt the [[cosmological constant]] must have played the crucial role in the universe's evolution from an Einsteinian steady state to its current expanding state, and most of his cosmological investigations focused on the constant's significance and characteristics. In ''The Mathematical Theory of Relativity,'' Eddington interpreted the cosmological constant to mean that the universe is "self-gauging".