Context:
In 1917, Einstein applied the General theory of relativity to model the structure of the universe as a whole. He apprehended that his equations predicted the universe to be either contracting or expanding. He wanted the universe to be eternal and unchanging, but this type of universe is not consistent with relativity. To fix this, Einstein modified the general theory by introducing a new notion,
the cosmological constant, which he called
Lambda.
[107] The purpose of Lambda was to rectify the effects of gravity and allow the whole system to stay balanced. With a positive cosmological constant, the universe could be an eternal static sphere. However, in 1929,
http://en.wikipedia.org/wiki/Edwin_Hubble confirmed that the universe is expanding, Einstein exclaimed after his
http://en.wikipedia.org/wiki/Mount_Wilson_Observatory visit with Hubble: "If there is no quasi-static world, then away with
the cosmological term!"
[108][109] and Einstein supposedly discarded the cosmological constant.