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

NASA delivers hardware for ESA dark energy mission

The European Space Agency's Euclid mission, set to launch in 2022, will investigate two of the biggest mysteries in modern astronomy: dark matter and dark energy. A team of NASA engineers recently delivered critical hardware ...

Successful launch for eROSITA X-ray telescope

The Russian-German Spektrum-Roentgen-Gamma (SRG) space mission successfully lifted off from the Baikonur cosmodrome on Saturday, July 13 at 14:31. Onboard is the eROSITA X-ray telescope, which was developed and built by a ...

Holes in the Universe sharpen cosmic measurements

Regions of the Universe containing very few or no galaxies—known as voids—can help measure cosmic expansion with much greater precision than before, according to new research.

Data visualization could reveal nature of the universe

As cosmologists ponder the universe—and other possible universes—the data available to them is so complex and vast that it can be extremely challenging for humans alone to comprehend.

eROSITA – the hunt for dark energy begins

On 21 June 2019 the Spektrum-Röntgen-Gamma (Spektr-RG / SRG) spacecraft will be launched from the Kazakh steppe, marking the start of an exciting journey. SRG will be carrying the German Extended ROentgen Survey with an ...

A new filter to better map the dark universe

The earliest known light in our universe, known as the cosmic microwave background, was emitted about 380,000 years after the Big Bang. The patterning of this relic light holds many important clues to the development and ...

Video: The making of the largest 3-D map of the universe

DESI, the Dark Energy Spectroscopic Instrument, will mobilize 5,000 swiveling robots – each one pointing a thin strand of fiber-optic cable – to gather the light from about 35 million galaxies.

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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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