Assuming the lambda-CDM model of cosmology is correct, the best current measurements indicate dark energy contributes 68% of the total energy in the present-day observable universe.
The density of dark energy is very low, much less than the density of ordinary matter or dark matter in reach galaxies.
In physical cosmology and astronomy, dark energy is an unknown form of energy affects the universe on the largest scales.
As of 2020, there are active areas of cosmology research aimed at understanding the fundamental nature of dark energy.
The mass–energy of dark matter and ordinary matter contributes 27% and 5%, respectively, and other components such as neutrinos and photons contribute a very small amount.
Since the 1990s, dark energy has been the largest accepted premise to account in support of the accelerated expansion.
Measurements of the cosmic microwave background suggest the universe began in a hot Big Bang, from which general relativity explains its evolution and the subsequent large scale motion. The cosmological constant can be formulated to be equivalent to the zero-point radiation of space i.e. the vacuum energy.
However, it dominates the mass–energy of the universe because it is uniform across space. Understanding the evolution of the universe requires Information of its starting conditions and its composition.
Some Ideas about dark Energy:
😊Variable dark energy models The density of the dark energy might own varied in time during the history of the universe.
😊Work done in 2013 established on the Planck spacecraft observations of the CMB gave a additional accurate estimate of 68.3% dark energy, 26.8% dark matter, and 4.9% ordinary matter.
😊The theoretical need in support of a type of extra energy is not matter or dark matter to form the observationally flat universe .
😊The existence of dark energy, in whatever form, is needed to reconcile the measured geometry of space with the total amount of matter in the universe.
😊During the 1980s, largest cosmological research focused on models with critical density in matter only, usually 95% cold dark matter and 5% ordinary matter .
😊Transformation in expansion over time Diagram representing the accelerated expansion of the universe due to dark energy.
😊Technical definition See also: Friedmann equations In standard cosmology, there are three components of the universe: matter, radiation, and dark energy.
😊Other mechanism driving acceleration Modified gravity See also: Massive gravity The evidence in support of dark energy is heavily dependent on the theory of general relativity.
😊The first direct evidence in support of dark energy came from supernova observations in 1998 of accelerated expansion in Riess et al.
😊Inflation postulates some repulsive force, qualitatively similar to dark energy, resulted in an enormous and exponential expansion of the universe slightly after the Big Bang.
😊Measuring the equation of state in support of dark energy is one of the biggest efforts in observational cosmology today.
😊First results from the SNLS reveal the average behavior of dark energy behaves like Einstein’s cosmological constant to a precision of 10%.
😊It generally predicts a slightly slower acceleration of the expansion of the universe than the cosmological constant.
😊In 1999, the Supernova Cosmology Project followed by suggesting the expansion of the universe is accelerating.
Source:
[1] Wikipedia Contributors. “Dark Energy.” Wikipedia, Wikimedia Foundation, 4 Nov. 2020, en.wikipedia.org/wiki/Dark_energy. Accessed 4 Nov. 2020.