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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.
One of his sons, Ulbo de Sitter (1902 – 1980), was a Dutch geologist, and one of Ulbo's sons was a Dutch sociologist Ulbo de Sitter (1930 – 2010). Another son of Willem, Aernout de Sitter (1905 – 15 September 1944 [7]), was the director of the Bosscha Observatory in Lembang, Indonesia (then the Dutch East Indies), where he studied the Messier 4 globular cluster.
In the approach of classical perturbation theory, we can start with Minkowski vacuum (or another very simple solution, such as the de Sitter lambdavacuum), introduce very small metric perturbations, and retain only terms up to some order in a suitable perturbation expansion—somewhat like evaluating a kind of Taylor series for the geometry of ...
Starobinsky originally used the semi-classical Einstein equations with free quantum matter fields. [4] However, it was soon realized that the late time inflation which is relevant for observable universe was essentially controlled by the contribution from a squared Ricci scalar in the effective action [ 5 ] [ 6 ]
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.
When it comes to hiring intelligent employees, it seems companies prefer people smarts more so than book smarts, a new survey finds. More than 70 percent of employers way they value emotional ...
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.