A rotating black hole is such an extreme force of nature that it drags surrounding time and space around with it. So it is only natural to ask whether black holes could be used as some sort of energy source. In 1969, mathematical physicist Roger Penrose proposed a method to do just this, now known as the " Penrose Process ."
The method could be used by sophisticated civilizations (aliens or future humans) to harvest energy by making "black hole bombs." Some of the physics required to do so, however, had never been experimentally verified — until now. Our study confirming the underlying physics has just been published in Nature Physics .
While you're here, how about this:
Bad Astronomy | Black hole disks illuminate themselves by bent light
I like to think that anyone is capable of some self-reflection. I would not, however, have thought to include black holes in that ability.
But it appears to be the case , at least for one such beast. And it's literal: Light emitted on one side of a disk around the black hole gets bent by the fierce gravity so much it travels back down to the disk on the other side, illuminating it, and gets reflected back up so we can see it.
The black hole is called XTE J1550−564, and it's located about 14,000 light years away from Earth. It has a mass of about 9 times the Sun's, so it's an average black hole in that respect. It's orbited by a star that's very roughly 10 million kilometers away from it; it's not clear what kind of star it is but it's likely something with around the mass of the Sun or a little less.
Scientists propose plan to determine if Planet Nine is a primordial black hole
"In the vicinity of a black hole, small bodies that approach it will melt as a result of heating from the background accretion of gas from the interstellar medium onto the black hole," said Siraj. "Once they melt, the small bodies are subject to tidal disruption by the black hole, followed by accretion from the tidally disrupted body onto the black hole.
Future searches for primordial black holes could be informed by the new calculation. "This method can detect or rule out trapped planet-mass black holes out to the edge of the Oort cloud, or about a hundred thousand astronomical units," said Siraj. "It could be capable of placing new limits on the fraction of dark matter contained in primordial black holes ."
Black hole: Expert confronts fears WHOLE UNIVERSE will collapse into supermassive giant | Science
He said: "Black holes generally 'feed' slowly [in a relative sense] such that the added mass is a small percentage of the total mass.
"This is true for a stellar-sized black hole [say with 5 times the mass of the Sun] pulling mass from a nearby companion star, or a supermassive black hole [say with 1 billion times the mass of the Sun] consuming a star with two to three solar masses.
"If we had sensitive enough instruments we could measure that change, but I don't believe we are quite there yet."
Not to change the topic here:
Mystery Object Blurs Line between Neutron Stars and Black Holes - Scientific American
Last Tuesday the Laser Interferometer Gravitational-Wave Observatory (LIGO) Scientific Collaboration announced the first conclusive detection of a stellar remnant falling into the so-called mass gap between neutron stars and black holes.
“I would rank this as definitely the most exciting announcement we’ve seen from LIGO since the original binary black hole discovery and then” the first detection of a neutron star collision, says Duncan Brown , a gravitational-wave astronomer at Syracuse University, who was not involved in the research. “We’re probing a new piece of astrophysical understanding of the universe.”
Care homes face staffing 'black hole' with new immigration bill - BBC News
Care homes could face a staffing "black hole" because of the impact of the government's immigration bill, care leaders have warned.
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Leaders of 37 national care organisations, including the NHS Confederation, have signed the letter to the prime minister.
The legislation will put EU and European Economic Area (EEA) citizens on an equal footing to immigrants from outside the bloc.
But the Cavendish Coalition said this points-based system currently does not include social care as the roles do not pass the proposed minimum salary threshold and "are not classed as a shortage occupation".
Most Massive Black Hole in the Universe Eats One Sun Per Day
In 2018, a team of scientists from the Research School of Astronomy and Astrophysics at the Australian National University discovered the fastest-growing supermassive black hole in the known universe, called J2157. This week, the same team released new research explaining exactly how massive the hole actually is as well as how much it eats to sustain its growth. The answer may shock you.
According to a press release about the research , the black hole is 34 billion times the mass of our sun and about 8,000 times bigger than the black hole at the center of the Milky Way. Research team member Dr. Christopher Onken explained it like this: "If the Milky Way's black hole wanted to grow that fat, it would have to swallow two-thirds of all the stars in our galaxy." Damn.
Supermassive binary black hole hunter: SKA pulsar timing array
Supermassive black holes are commonly found in the center of galaxies and evolve with their hosts. SMBBHs are thus expected to exist in close galaxy pairs. However, none has been unequivocally detected.
The research team carried out semi-analytical numerical simulation to estimate the number of detectable SMBBHs with SKA Pulsar Timing Array (SKA-PTA).
Based on infrared galaxy samples and statistical assumptions of the SMBBH population, the team calculated their low-frequency gravitational wave characteristics at different redshifts.
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