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The measurements from ancient and dormant galaxies show black holes growing more than expected, aligning with a phenomenon predicted in Einsteinâs theory of gravity. The result potentially means nothing new has to be added to our picture of the Universe to account for dark energy: black holes combined with Einsteinâs gravity are the source.
A supermassive black hole at the centre of a galaxy some 8.5 billion years way has ripped apart a nearby star, producing some of the most luminous jets ever seen.
When stars and other objects stray too close to a supermassive black hole they are destroyed by the black holeâs immense gravity.
These occurrences, known as tidal-disruption events (TDEs), result in a circling disk of material that is slowly pulled into the black hole and very occasionally, as in the case of supermassive black hole AT2022cmc, ejecting bright beams of material travelling close to the speed of light.
Two decades of monitoring from W. M. Keck Observatory on Mauna Kea in Hawaiʻi reveals a peculiar cloud dubbed X7 being pulled apart as it accelerates toward the supermassive black hole at the center of our Milky Way galaxy.
Astronomers from the UCLA Galactic Center Orbits Initiative (GCOI) and Keck Observatory have been tracking the evolution of this dusty gas filament since 2002; high-angular resolution near-infrared images captured with Keck Observatoryâs powerful adaptive optics system show X7 has become so elongated that it now has a length of 3,000 times the distance between the Earth and sun (or 3,000 astronomical units).
The study is published in todayâs issue of The Astrophysical Journal.
When two black holes collide into each other to form a new bigger black hole, they violently roil spacetime around them, sending ripples, called gravitational waves, outward in all directions. Previous studies of black hole collisions modeled the behavior of the gravitational waves using what is known as linear math, which means that the gravitational waves rippling outward did not influence, or interact, with each other. Now, a new analysis has modeled the same collisions in more detail and revealed so-called nonlinear effects.
âNonlinear effects are what happens when waves on the beach crest and crash,â says Keefe Mitman, a Caltech graduate student who works with Saul Teukolsky (Ph. D. â74), the Robinson Professor of Theoretical Astrophysics at Caltech with a joint appointment at Cornell University.
âThe waves interact and influence each other rather than ride along by themselves. With something as violent as a black hole merger, we expected these effects but had not seen them in our models until now. New methods for extracting the waveforms from our simulations have made it possible to see the nonlinearities.â
The new modeling method could help scientists better understand the inner workings of black hole mergers.
A team of researchers from the US has developed an improved method for modeling the mergers of colossal black holes.
Their improved method could help shed new light on the structure of merging black holes and their role in the universe.
Researchers have created a new optical illusion that makes your brain try to predict the future â namely, entering a dark tunnel.
Posted in cosmology
Black holes are bizarre things, even by the standards of astronomers. Their mass is so great, it bends space around them so tightly that nothing can escape, even light itself.
And yet, despite their famous blackness, some black holes are quite visible. The gas and stars these galactic vacuums devour are sucked into a glowing disk before their one-way trip into the hole, and these disks can shine more brightly than entire galaxies.
Stranger still, these black holes twinkle. The brightness of the glowing disks can fluctuate from day to day, and nobody is entirely sure why.
Posted in cosmology
Interview with Prof. Sean Carroll, Research Professor of Physics at Caltech and an External Professor at the Santa Fe Institute. We mainly talk about quantum spacetime: the idea that our familiar spacetime might be actually emergent from some complex quantum mechanical system. We cover entanglement, decoherence, entropic gravity, the AdS/CFT correspondence, string theory, black holes, along with several philosophical questions concerning these topics, including reduction and emergence, substantivalism vs. relationalism, monism, and much more.
Seanâs website: https://www.preposterousuniverse.com/
His recent book concerning these topics: https://www.preposterousuniverse.com/somethingdeeplyhidden/
His papers on these topics can be found here: https://www.preposterousuniverse.com/research/annotated-publications/
His podcast: https://www.preposterousuniverse.com/podcast/
And his Twitter: https://twitter.com/seanmcarroll/
Scientists try to unravel the birth, growth and power of black holes, some of the most forceful yet difficult-to-detect objects in our universe.
It was only last year that astronomers were finally able to unveil the first pictures of the supermassive black hole at the center of our Milky Way galaxy. But you couldnât actually see the black hole itself, not directly. Thatâs because it is so dense that its gravitational pull prevents even light from escaping.
But the image of Sagittarius A, as our galaxyâs black hole is known, revealed a glowing halo of gas around the objectâan object that we now know has a million times more mass than our sun.
