“the predictions of the standard model of the universe appear to be at odds with some recent observations.”
Right now, it looks like the cosmology is at a tipping point.
Category: cosmology – Page 43
A small black hole must work harder against gravity to keep from collapsing. In rapidly rotating black holes, the Ni shell would collapse to a torus, as possibly reflected in the dramatic photos of supermassive black holes.
At a deeper level, the gravity/Λ mechanism might be seen as a kind of quantum overlay of the Ni solutions, a possible step towards reconciliation of the quantum gravity and general relativity perspectives.
Cosmologists will not be quick to endorse a shell universe. There is still much heavy lifting still to do, for instance, in matching the Ni solutions to the observed universe. Dark matter and dark energy will not lightly be cast aside. But if I am right, the universe is not as you may always have thought.
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If we discover how to connect quantum mechanics with general relativity we’ll pretty much win physics. There are multiple theories that claim to do this, but it’s notoriously difficult to test them. They seem to require absurd experiments like a particle collider the size of a galaxy. Or we could try to physics smarter, instead of physicsing harder. Let’s talk about some ideas for quantum gravity experiments that can be done on a non-galaxy-sized lab bench, and in some cases already have been done.
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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.”