In physical cosmology, the cosmological constant (usually denoted by the Greek capital letter lambda: Λ) is equivalent to an energy density in otherwise empty space. It was originally proposed by Albert Einstein as a modification of his original theory of general relativity to achieve a stationary universe. Einstein abandoned the concept after the observation of the Hubble redshift indicated that the universe might not be stationary, as he had based his theory on the idea that the universe is unchanging. However, a number of observations including the discovery of cosmic acceleration in 1998 have revived the cosmological constant, and the current standard model of cosmology includes this term.
Read more about Cosmological Constant: Equation, History, Positive Value
Famous quotes containing the word constant:
“There exists a black kingdom which the eyes of man avoid because its landscape fails signally to flatter them. This darkness, which he imagines he can dispense with in describing the light, is error with its unknown characteristics.... Error is certainty’s constant companion. Error is the corollary of evidence. And anything said about truth may equally well be said about error: the delusion will be no greater.”
—Louis Aragon (1897–1982)