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 ...
Astronomy
Jun 18, 2019
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48
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 ...
General Physics
May 08, 2019
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480
Now that they've identified the Higgs boson, scientists at the Large Hadron Collider have set their sights on an even more elusive target.
General Physics
Apr 18, 2019
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2602
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.
Astronomy
Apr 15, 2019
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144
The world is finally about to see a black hole—not an artist's impression or a computer-generated likeness, but the real thing.
Astronomy
Apr 10, 2019
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The world, it seems, is soon to see the first picture of a black hole.
Astronomy
Apr 06, 2019
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17629
On April 1, the dome of the Mayall Telescope near Tucson, Arizona, opened to the night sky, and starlight poured through the assembly of six large lenses that were carefully packaged and aligned for a new instrument that ...
Astronomy
Apr 03, 2019
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154
Some of the bacteria that live in ponds, lakes and other freshwater environments grow faster during the day, even though they don't take in sunlight as an energy source, according to researchers at the University of Delaware. ...
Cell & Microbiology
Feb 26, 2019
0
21
Combining Einstein's theory of relativity with one of the most powerful telescopes in the world has helped an international team of researchers measure where and how dark matter structures grow in the universe. Their analysis ...
Astronomy
Feb 13, 2019
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71
Dark energy and dark matter comprise 96 percent of the total mass of the universe. Two main hypotheses about the nature of dark matter are presently debated. One posits that dark matter consists of massive compact halo objects; ...
Astronomy
Feb 06, 2019
5
180
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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