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English: The number-line is broken into the two major classifications of dark matter particle hypotheses, particle-like dark matter (e.g. WIMPs) and wave-like dark matter (e.g. axions). The Compton wavelength and Compton frequency of the particles are shown for comparison, along with a few major reference points.
In standard cosmology, there are three components of the universe: matter, radiation, and dark energy. This matter is anything whose energy density scales with the inverse cube of the scale factor, i.e., ρ ∝ a −3, while radiation is anything whose energy density scales to the inverse fourth power of the scale factor (ρ ∝ a −4).
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 ...
It is due to dark matter that galaxies are able to keep their shape, with the mass of dark matter creating enough gravitational force to hold the stars that make up a galaxy together. Dark energy, however, is a substance or force responsible for the accelerating expansion of the universe over time. [2]
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.
Michael S. Turner (born July 29, 1949) [1] is an American theoretical cosmologist who coined the term dark energy in 1998. [2] He is the Rauner Distinguished Service Professor Emeritus of Physics at the University of Chicago, [3] having previously served as the Bruce V. & Diana M. Rauner Distinguished Service Professor, [4] and as the assistant director for Mathematical and Physical Sciences ...
In cosmology and physics, cold dark matter (CDM) is a hypothetical type of dark matter.According to the current standard model of cosmology, Lambda-CDM model, approximately 27% of the universe is dark matter and 68% is dark energy, with only a small fraction being the ordinary baryonic matter that composes stars, planets, and living organisms.
In these models, the quintessence field has a density which closely tracks (but is less than) the radiation density until matter-radiation equality, which triggers quintessence to start having characteristics similar to dark energy, eventually dominating the universe. This naturally sets the low scale of the dark energy. [12]