Posted on 11/04/2018 9:33:21 AM PST by ETL
Astronomers using the GRAVITY instrument on ESOs Very Large Telescope Interferometer (VLTI) have detected flares of infrared radiation coming from the accretion disk around Sagittarius A*, the 4-million-solar-mass black hole at the heart of our Milky Way Galaxy.
The flares the GRAVITY instrument detected provide long-awaited confirmation that the object in the center of our Galaxy is a supermassive black hole.
The flares originate from material orbiting very close to the black holes event horizon making these the most detailed observations yet of material orbiting this close to a black hole.
While some matter in the accretion disk the belt of gas orbiting Sagittarius A* at relativistic speeds can orbit the black hole safely, anything that gets too close is doomed to be pulled beyond the event horizon.
The closest point to a black hole that material can orbit without being irresistibly drawn inwards by the immense mass is known as the innermost stable orbit, and it is from here that the observed flares originate.
Its mind-boggling to actually witness material orbiting a massive black hole at 30% of the speed of light, said team member Dr. Oliver Pfuhl, a researcher at the Max Planck Institute for Extraterrestrial Physics, Germany.
GRAVITYs tremendous sensitivity has allowed us to observe the accretion processes in real time in unprecedented detail.
(Excerpt) Read more at sci-news.com ...
I believe 98% of this article and science concerning black wholes and deep space will eventually be proven wrong ...
Wait, black holes evaporate? The mass is turned into
energy until nothing is left?
Well, I guess we'll know in 10 or so billion years from now. :)
Ask Leonard or Sheldon.
Nothing lasts forever, not even black holes. According to Stephen Hawking, black holes will evaporate over vast periods of time. But how, exactly, does this happen?
The actor Stephen Hawking is best known for his cameo appearances in Futurama and Star Trek, you might surprised to learn that hes also a theoretical astrophysicist. Is there anything that guy cant do?
One of the most fascinating theories he came up with is that black holes, the Universes swiffer, can actually evaporate over vast periods of time.
Quantum theory suggests there are virtual particles popping in and out of existence all the time. When this happens, a particle and its antiparticle appear, and then they recombine and disappear again.
When this takes place near an event horizon, strange things can happen. Instead of the two particles existing for a moment and then annihilating each other, one particle can fall into the black hole, and the other particle can fly off into space. Over vast periods of time, the theory says that this trickle of escaping particles causes the black hole to evaporate.
Wait, if these virtual particles are falling into the black hole, shouldnt that make it grow more massive? How does that cause it to evaporate? If I add pebbles to a rock pile, doesnt my rock pile just get bigger?
It comes down to perspective. From an outside observer watching the black holes event horizon, it appears as if theres a glow of radiation coming from the black hole. If that was all that was happening, it would violate the law of thermodynamics, as energy can neither be created nor destroyed. Since the black hole is now emitting energy, it needs to have given up a little bit of its mass to provide it.
Lets try another way to think about this. A black hole has a temperature. The more massive it is, the lower its temperature, although its still not zero.
From now and until far off into the future, the temperature of the largest black holes will be colder than the background temperature of the Universe itself. Light from the cosmic microwave background radiation will fall in, increasing its mass.
Now, fast forward to when the background temperature of the Universe drops below even the coolest black holes. Then theyll slowly radiate heat away, which must come from the black hole converting its mass into energy.
The rate that this happens depends on the mass. For stellar mass black holes, it might take 10^67 years to evaporate completely.
For the big daddy supermassive ones at the cores of galaxies, youre looking at 10^100. Thats a one, followed by 100 zero years. Thats huge number, but just like any gigantic and finite number, its still less than infinity. So over an incomprehensible amount of time, even the longest living objects in the Universe our mighty black holes will fade away into energy.
One last thing, the Large Hadron Collider might be capable of generating microscopic black holes, which would last for a fraction of a second and disappear in a burst of Hawking radiation. If they find them, then Hawking might want to the acting on hold and focus on physics.
Nothing is eternal, not even black holes. Over the longest time frames were pretty sure theyll evaporate away into nothing. The only way to find out is to sit back and watch, well maybe its not the only way.
Does the idea of these celestial nightmares evaporating fill you with existential sadness? Feel free to share your thoughts with others in the comments below.
https://www.universetoday.com/119794/how-do-black-holes-evaporate/
Ron Cowen
October 2013
Old black holes never die, they just fade away. So says veteran cosmologist George Ellis of the University of Cape Town in South Africa, who suggests that the cosmos may be littered with an untold number of shrunken black hole remnants.
Ellis speculative report, posted on 17 October on the preprint server arXiv (G. F. R. Ellis http://arxiv.org/abs/1310.4771; 2013), seems to undermine the seminal work of Stephen Hawking, a cosmologist at the University of Cambridge, UK. In 1974, Hawking calculated that, owing to quantum effects, black holes are not entirely black: some particles escape the black holes gravitational barrier, known as the event horizon. For a solar-mass black hole, these particles, known as Hawking radiation, would be emitted over the course of 1067 years until the object vanished without a trace (S. W. Hawking Nature 248, 3031; 1974).
Although many physicists are sceptical about Elliss work, it highlights a long-running debate over the ultimate fate of black holes. Uncertainties abound because of the difficulties in reconciling quantum theory which predicts the Hawking radiation and Einsteins classical theory of gravitation, which defines a black holes structure. This is very much a living issue that people are confused about, says Vijay Balasubramanian, a string theorist at the University of Pennsylvania in Philadelphia.
The debate also touches on one of the most cherished beliefs about the Universe: that information is always preserved. If black holes evaporate, then the information they contain may die along with them. By contrast, a black hole remnant would offer a way in which information might be preserved (even if it could never be extracted). By serving as a storehouse, a remnant could be a fantastic way of resolving all the issues we have with black holes, says theoretical physicist Jeff Murugan of the University of Cape Town.
In Hawkings original view, quantum theory permits large fluctuations in energy for brief moments of time. As a consequence, the vacuum of space seethes with particleantiparticle pairs that continually pop in and out of existence (see Vanishing act). When this occurs at the event horizon, one member of a particle pair could be sucked into the black hole, whereas the other could escape as Hawking radiation, depleting the black holes mass.
But Ellis says that this radiation has another effect. According to Einstein, any source of mass or energy distorts space. A black hole, a body so massive that space closes in on itself, is an extreme example of that distortion. The Hawking radiation would add even more distortion, Ellis says, and so, too, would the ubiquitous photons from the cosmic microwave background, the bath of radiation left over from the Big Bang. He says that these two types of radiation bend space-time in such a way that the region from which the Hawking radiation is generated eventually gets pushed back behind the event horizon. Once it has been relocated, the radiation can no longer escape and the black hole plateaus at a constant mass.
The analysis is more of an essay than a full-blown study, says string theorist Samir Mathur of Ohio State University in Columbus, because Ellis does not perform a thorough calculation for the bending effect of the radiation. Other physicists say that Ellis is probably incorrect. Nonetheless, Balasubramanian says, the paper is an example of physicists innate dissatisfaction with evaporating black holes. The stuff radiates in a weird way, information is lost and then we turn intellectual somersaults to try to account for why the information isnt lost, he says.
But black hole remnants do not offer a perfect solution to the problem of information loss, either. To contain all the information originally stored in a large black hole, the tiny remnants would need to have an infinite number of internal states which would violate quantum theory, says Mathur.
In 1997, Mathur found a potential way around this problem. He and his colleagues used string theory, a way of marrying quantum theory and gravity, to describe all of the possible states of the gravitational field of black holes. They found that these states lay just outside the classical event horizon in a fuzzball of quantum states. If the fuzzball was the black holes true boundary, then there would be no Hawking radiation emitted from the event horizon, no evaporation and no information loss, he says.
Last year, others proposed a more violent approach to the problem of information loss. They suggested that the particles in the Hawking radiation did not behave randomly but were instead entangled with each other in such a way that they could be messengers from the darkness, conveying information that had been stored in the black hole. But that entanglement had its own consequence: an enormous amount of energy would be unleashed at the event horizon, such that anything falling in would be instantly immolated (see Nature 496, 2023; 2013).
The ongoing struggle to preserve the precepts of quantum theory without losing information may offer clues about how and where quantum physics begins to significantly modify Einsteins theory of gravity, says Matt Visser, a cosmologist at Victoria University of Wellington. The conventional picture holds that quantum theory makes big corrections to gravity only well inside the event horizon, near the black holes singularity the point at which the density of matter becomes infinite. But some physicists think that quantum physics may be blurring the sharp boundary of the event horizon itself. Elliss work, Visser says, puts a stronger spotlight on such speculations.
https://www.nature.com/news/black-holes-shrink-but-endure-1.14051
Life sure is complicated, and then you fall into
a black hole.
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