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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).
Dark energy does not exist, some scientists have claimed – which could help get rid of one of the universe’s biggest mysteries. ... ‘Supernovae evidence for foundational change to ...
The simplest explanation for dark energy is that it is a cosmological constant or vacuum energy; in this case w = −1. This leads to the Lambda-CDM model , which has generally been known as the Standard Model of Cosmology from 2003 through the present, since it is the simplest model in good agreement with a variety of recent observations.
The measured dark energy density is Ω Λ ≈ 0.690; the observed ordinary (baryonic) matter energy density is Ω b ≈ 0.0482 and the energy density of radiation is negligible. This leaves a missing Ω dm ≈ 0.258 which nonetheless behaves like matter (see technical definition section above) – dark matter.
The physical nature of dark energy is at present unknown," Huterer said. The new findings appear to corroborate the current standard model of cosmology that includes the theory of general relativity.
This argument depends on the vacuum energy density being constant throughout spacetime, as would be expected if dark energy were the cosmological constant. There is no evidence that the vacuum energy does vary, but it may be the case if, for example, the vacuum energy is (even in part) the potential of a scalar field such as the residual ...
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 ...
Dark energy is one of the greatest mysteries in science today. One of the simplest explanations is that it is a “cosmological constant” – a result of the energy of empty space itself – an ...