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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).
In physics, quintessence is a hypothetical form of dark energy, more precisely a scalar field minimally coupled to gravity, postulated as an explanation of the observation of an accelerating rate of expansion of the universe.
A cosmological constant has negative pressure, =, which contributes to the stress–energy tensor that, according to the general theory of relativity, causes accelerating expansion. 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 ...
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 ...
The findings announced on Tuesday are part of a years-long study of the history of the cosmos focusing upon dark energy, an invisible and enigmatic force that is accelerating the ongoing expansion ...
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.
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.
Dark energy dominates the total energy (74%) while dark matter (22%) constitutes most of the mass. Of the remaining baryonic matter (4%), only one tenth is compact. In February 2015, the European-led research team behind the Planck cosmology probe released new data refining these values to 4.9% ordinary matter, 25.9% dark matter and 69.1% dark ...