Related topics: universe · dark matter · galaxies · white dwarfs · big bang

Activity discovered on largest comet ever found

A newly discovered visitor to the outer edges of our solar system has been shown to be the largest known comet ever, thanks to the rapid response telescopes of Las Cumbres Observatory. The object, which is named Comet C/2014 ...

Improving lab constraint on exotic spin interaction

Prof. Du Jiangfeng, Prof. Rong Xing, and their colleagues from the Key Laboratory of Micromagnetic Resonance, University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS) have set the most ...

Hunting dark energy with gravity resonance spectroscopy

Dark Energy is widely believed to be the driving force behind the universe's accelerating expansion, and several theories have now been proposed to explain its elusive nature. However, these theories predict that its influence ...

Giant comet found in outer solar system by Dark Energy Survey

A giant comet from the outskirts of our solar system has been discovered in six years of data from the Dark Energy Survey. Comet Bernardinelli-Bernstein is estimated to be about 1000 times more massive than a typical comet, ...

Astronomers discover three new faint dwarf galaxies

By analyzing the data from the Dark Energy Survey (DES), an international team of astronomers has conducted a search for nearby faint dwarf galaxies. In result, they detected three such objects around the Sculptor Galaxy. ...

Dark Energy Spectroscopic Instrument (DESI) starts 5-year survey

A five-year quest to map the universe and unravel the mysteries of "dark energy" is beginning officially today, May 17, at Kitt Peak National Observatory near Tucson, Arizona. To complete its quest, the Dark Energy Spectroscopic ...

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Dark energy

In physical cosmology and astronomy, dark energy is a hypothetical form of energy that permeates all of space and tends to increase the rate of expansion of the universe. Dark energy is the most popular way to explain recent observations that the universe appears to be expanding at an accelerating rate. In the standard model of cosmology, dark energy currently accounts for 74% of the total mass-energy of the universe.

Two proposed forms for dark energy are the cosmological constant, a constant energy density filling space homogeneously, and scalar fields such as quintessence or moduli, dynamic quantities whose energy density can vary in time and space. Contributions from scalar fields that are constant in space are usually also included in the cosmological constant. The cosmological constant is physically equivalent to vacuum energy. Scalar fields which do change in space can be difficult to distinguish from a cosmological constant because the change may be extremely slow.

High-precision measurements of the expansion of the universe are required to understand how the expansion rate changes over time. In general relativity, the evolution of the expansion rate is parameterized by the cosmological equation of state. Measuring the equation of state of dark energy is one of the biggest efforts in observational cosmology today.

Adding the cosmological constant to cosmology's standard FLRW metric leads to the Lambda-CDM model, which has been referred to as the "standard model" of cosmology because of its precise agreement with observations. Dark energy has been used as a crucial ingredient in a recent attempt to formulate a cyclic model for the universe.

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