Matt WillemsenNov 15, 2023
Kind of a Drag
Supermassive black hole at the heart of the Milky Way is approaching the cosmic speed limit, dragging space-time along with it
Supermassive black hole Sagittarius A* is spinning nearly as fast as it can, dragging the very fabric of space-time with it and shaping the heart of the Milky Way.
https://www.livescience.com/space/black-holes/our-galaxys-monster-black-hole-is-spinning-at-top-speed-and-its-dragging-everything-along #Supermassive #BlackHole #MilkyWay #cosmic #SpeedLimit #SagittariusAPrime #AngularMomentum #FrameDragging
Supermassive black hole at the heart of the Milky Way is approaching the cosmic speed limit, dragging space-time along with it

Supermassive black hole Sagittarius A* is spinning nearly as fast as it can, dragging the very fabric of space-time with it and shaping the heart of the Milky Way.

Live Science
RichardSep 20, 2023

Black holes eat faster than previously expected: New finding might explain why quasars flare and fade so quickly

https://phys.org/news/2023-09-black-holes-faster-previously-quasars.html

"One cycle of the endlessly repeating eat-refill-eat process takes mere months—a shockingly fast timescale compared to the hundreds of years that researchers previously proposed."

https://arxiv.org/abs/2210.10053

#astronomy #Astrodon #blackholes #framedragging.

Black holes eat faster than previously expected: New finding might explain why quasars flare and fade so quickly

A new Northwestern University-led study is changing the way astrophysicists understand the eating habits of supermassive black holes.

Phys.org
Ashkbiz DanehkarNov 9, 2022
"Covariant Evolution of Gravitoelectromagnetism" published by Universe #mdpiUniverse https://t.co/LLqvh497ID #mdpiuniverse via @Universe_MDPI https://t.co/W8kMT8VMzn #cosmology #Universe #gravitomagnetism #FrameDragging @MDPIOpenAccess https://t.co/lCC2G0fpR8
Covariant Evolution of Gravitoelectromagnetism

The long-range gravitational terms associated with tidal forces, frame-dragging effects, and gravitational waves are described by the Weyl conformal tensor, the traceless part of the Riemann curvature that is not locally affected by the matter field. The Ricci and Bianchi identities provide a set of dynamical and kinematic equations governing the matter coupling and evolution of the electric and magnetic parts of the Weyl tensor, so-called gravitoelectric and gravitomagnetic fields. A detailed analysis of the Weyl gravitoelectromagnetic fields can be conducted using a number of algebraic and differential identities prescribed by the 1+3 covariant formalism. In this review, we consider the dynamical constraints and propagation equations of the gravitoelectric/-magnetic fields and covariantly debate their analytic properties. We discuss the special conditions under which gravitational waves can propagate, the inconsistency of a Newtonian-like model without gravitomagnetism, the nonlinear generalization to multi-fluid models with different matter species, as well as observational effects caused by the Weyl fields via the kinematic quantities. The 1+3 tetrad and 1+1+2 semi-covariant methods, which can equally be used for gravitoelectromagnetism, are briefly explained, along with their correspondence with the covariant formulations.

MDPI
Ashkbiz DanehkarNov 9, 2022
Special Issue: "Frame-Dragging and Gravitomagnetism"
https://t.co/yPlahNBnel #mdpiuniverse #gravitomagnetism #FrameDragging @Universe_MDPI @MDPIOpenAccess