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Category: cosmology – Page 42
A brief explanation of how superfluid dark matter can combine fluid dark matter and modified gravity.
For galaxy clusters and for the cosmic microwave background, dark matter matter is the better explanation. But to explain galactic rotation curves and other properties of galaxies, modified gravity is the better explanation.
Until now, physicists have taken an either-or approach. In this video I argue that the answer may be a combination of both. This idea may be realized through dark matter which forms a superfluid. In this case dark matter has two phases, a normally fluid phase and a superfluid phase. In the latter phase, it has no internal friction and appears like modified gravity.
Taken together, so I argue, this explains the existing data best.
The eROSITA telescope’s detailed pictures are among the most precise cosmological measurements ever made.
Scientists say microscopic wormholes could explain discrepancies in cosmological constants and affect our understanding of quantum mechanics and dark energy.
We revise the dynamics of interacting vector-like dark energy, a theoretical framework proposed to explain the accelerated expansion of the universe. By investigating the interaction between vector-like dark energy and dark matter, we analyze its effects on the cosmic expansion history and the thermodynamics of the accelerating universe. Our results demonstrate that the presence of interaction significantly influences the evolution of vector-like dark energy, leading to distinct features in its equation of state and energy density. We compare our findings with observational data and highlight the importance of considering interactions in future cosmological studies.
New James Webb Space Telescope observations may have done with one of the longest-standing tensions in cosmology.
For almost a decade, astronomers have been struggling with a nagging mismatch between two different ways of determining the Hubble constant — a measure of the current expansion rate of the universe. This mismatch, known as the Hubble tension, has led to claims that new physics might be needed to solve the issue. (Read about the “constant controversy” in the June 2019 issue of Sky & Telescope.)
But a detailed analysis of a new set of James Webb Space Telescope (JWST) observations now suggests that the problem may not exist. “As Carl Sagan said, extraordinary claims require extraordinary evidence,” says Wendy Freedman (University of Chicago), “and I don’t see extraordinary evidence.”
Astronomers capture rare black hole awakening, witnessing a galaxy’s core flare up in real-time.
Neutron stars are timelike matter with a maximum mass of about 2.34 solar masses in quantum chromodynamics (the strong color force). Black holes are spacelike matter that have no maximum mass, but a minimum mass of 2.35 solar masses. Indeed, black holes have been identified with millions or billions of solar masses.
The origins of aptly named supermassive black holes—which can weigh in at more than a million times the mass of the sun and reside in the center of most galaxies—remain one of the great mysteries of the cosmos.