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The density of dark matter in an expanding universe decreases more quickly than dark energy, and eventually the dark energy dominates. Specifically, when the volume of the universe doubles, the density of dark matter is halved, but the density of dark energy is nearly unchanged (it is exactly constant in the case of a cosmological constant).
Studies with quintessence dark energy found that it dominates gravitational collapse in a spacetime simulation, based on the holographic thermalization. These results show that the smaller the state parameter of quintessence is, the harder it is for the plasma to thermalize.
Since the 1990s, studies have shown that, assuming the cosmological principle, around 68% of the mass–energy density of the universe can be attributed to dark energy. [6] [7] [8] The cosmological constant Λ is the simplest possible explanation for dark energy, and is used in the standard model of cosmology known as the ΛCDM model.
The fraction of the total energy density of our (flat or almost flat) universe that is dark energy, , is estimated to be 0.669 ± 0.038 based on the 2018 Dark Energy Survey results using Type Ia supernovae [8] or 0.6847 ± 0.0073 based on the 2018 release of Planck satellite data, or more than 68.3 % (2018 estimate) of the mass–energy density ...
In astronomy and cosmology, the dark fluid theory attempt to explain dark matter and dark energy in a single framework, as suggested by cosmologist Alexandre Arbey in 2005. [1] [2] The theory proposes that dark matter and dark energy are not separate physical phenomena, nor do they have separate origins, but that they are strongly linked together and can be considered as two facets of a single ...
[29] [30] Anthropic arguments gradually gained credibility among many physicists after the discovery of dark energy and the development of the theoretical string theory landscape, but are still derided by a substantial skeptical portion of the scientific community as being problematic to verify. Proponents of anthropic solutions are themselves ...
This relationship between pressure and energy density served as the initial theoretical prediction of dark energy. [ citation needed ] In the early 1970s, Yakov Zeldovich noticed the flatness and horizon problems of Big Bang cosmology; before his work, cosmology was presumed to be symmetrical on purely philosophical grounds. [ 6 ]
Many energy conditions are known to not correspond to physical reality—for example, the observable effects of dark energy are well known to violate the strong energy condition. [ 2 ] [ 3 ] In general relativity, energy conditions are often used (and required) in proofs of various important theorems about black holes, such as the no hair ...