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The Einstein–de Sitter universe is a model of the universe proposed by Albert Einstein and Willem de Sitter in 1932. [1] On first learning of Edwin Hubble's discovery of a linear relation between the redshift of the galaxies and their distance, [2] Einstein set the cosmological constant to zero in the Friedmann equations, resulting in a model of the expanding universe known as the Friedmann ...
A de Sitter universe is a cosmological solution to the Einstein field equations of general relativity, named after Willem de Sitter.It models the universe as spatially flat and neglects ordinary matter, so the dynamics of the universe are dominated by the cosmological constant, thought to correspond to dark energy in our universe or the inflaton field in the early universe.
De Sitter space and anti-de Sitter space are named after Willem de Sitter (1872–1934), [1] [2] professor of astronomy at Leiden University and director of the Leiden Observatory. Willem de Sitter and Albert Einstein worked closely together in Leiden in the 1920s on the spacetime structure of our universe.
In 1931, Einstein accepts the theory of an expanding universe and proposes, in 1932 with the Dutch physicist and astronomer Willem de Sitter, a model of a continuously expanding universe with zero cosmological constant (Einstein–de Sitter spacetime).
Analogous results are known for lambdavac perturbations of the de Sitter lambdavacuum (Helmut Friedrich) and for electrovacuum perturbations of the Minkowski vacuum (Nina Zipser). In contrast, anti-de Sitter spacetime is known to be unstable under certain conditions. [4] [5]
The de Sitter–Schwarzschild spacetime is a combination of the two, and describes a black hole horizon spherically centered in an otherwise de Sitter universe. An observer who hasn't fallen into the black hole, and who can still see the black hole despite the inflation is sandwiched between the two horizons.
de Sitter space, often referred to as the dS cosmological model, anti-de Sitter space, often referred to as the AdS cosmological model, de Sitter–Schwarzschild metric, which models a spherically symmetric massive object immersed in a de Sitter universe (and likewise for AdS), Kerr–de Sitter metric, the rotating generalization of the latter,
In physics, the Lemaître–Tolman metric, also known as the Lemaître–Tolman–Bondi metric or the Tolman metric, is a Lorentzian metric based on an exact solution of Einstein's field equations; it describes an isotropic and expanding (or contracting) universe which is not homogeneous, [1] [2] and is thus used in cosmology as an alternative to the standard Friedmann–Lemaître–Robertson ...