Search results
Results from the WOW.Com Content Network
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 astronomy, dark matter is an invisible and hypothetical form of matter that does not interact with light or other electromagnetic radiation.Dark matter is implied by gravitational effects which cannot be explained by general relativity unless more matter is present than can be observed.
In recent years, light dark matter has become popular due in part to the many benefits of the theory. Sub-GeV dark matter has been used to explain the positron excess in the Galactic Center observed by INTEGRAL, excess gamma rays from the Galactic Center [7] and extragalactic sources. It has also been suggested that light dark matter may ...
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 [7] 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 chemistry, many reactions depend on the absorption of photons to provide the energy needed to overcome the activation energy barrier and hence can be labelled light-dependent. Such reactions range from the silver halide reactions used in photographic film to the creation and destruction of ozone in the upper atmosphere .
In cosmology, the cosmic coincidence is the observation that at the present epoch of the universe's evolution, the energy densities associated with dark matter and dark energy are of the same order of magnitude, leading to their comparable effects on the dynamics of the cosmos. [1]
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 ...