A team of astronomers using the Canada-France-Hawaii Telescope discovered a new stellar stream emanating from the M92 globular cluster. This new stream suggests that M92 is actively being disrupted by tidal forces caused ...
Astronomy
Oct 15, 2020
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207
Researchers at the National Institute of Standards and Technology (NIST) and their colleagues have proposed a novel method for finding dark matter, the cosmos's mystery material that has eluded detection for decades. Dark ...
Space Exploration
Oct 14, 2020
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82
A team of US astrophysicists has produced one of the most precise measurements ever made of the total amount of matter in the Universe, a longtime mystery of the cosmos.
Astronomy
Sep 29, 2020
3
54
One-hundred million light years away from Earth, an unusual supernova is exploding.
Astronomy
Sep 10, 2020
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824
Astronomers have known for two decades that the expansion of the universe is accelerating, but the physics of this expansion remains a mystery. Now, a team of researchers at the University of Hawai'i at Mānoa have made a ...
Astronomy
Sep 01, 2020
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4128
The nature of dark matter remains one of the great unsolved puzzles of fundamental physics. Unexplained by the Standard Model, dark matter has led scientists to probe new physics models to understand its existence. Many such ...
General Physics
Aug 13, 2020
3
245
When it launches in the mid-2020s, NASA's Nancy Grace Roman Space Telescope will create enormous panoramic pictures of space in unprecedented detail. The mission's wide field of view will enable scientists to conduct sweeping ...
Astronomy
Jul 25, 2020
0
80
For only the second time ever, astrophysicists have spotted a spectacular flash of ultraviolet (UV) light accompanying a white dwarf explosion.
Astronomy
Jul 23, 2020
3
365
Dark energy is one of the greatest mysteries in science today. We know very little about it, other than it is invisible, it fills the whole universe, and it pushes galaxies away from each other. This is making our cosmos ...
Astronomy
Jul 23, 2020
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183
The Sloan Digital Sky Survey (SDSS) released today a comprehensive analysis of the largest three-dimensional map of the universe ever created, filling in the most significant gaps in our possible exploration of its history.
Astronomy
Jul 20, 2020
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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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