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The monster black hole in the center of the Milky Way is strangely silent, and astronomers now think they know why.
Lines of invisible magnetic fields are wrapping around him – researchers had already suspected him. But new images show that these invisible lines form a structure that expands the light-years into space and can be powerful enough to prevent materials from falling into the black hole. And if gigantic magnetic fields spill material into an orbit out of reach of the black hole, this could explain why it is mostly knocked out. In fact, it is so weak that a magnetar can surpass it in the sky.
"The spiral shape of the magnetic field drives the gas into an orbit around the black hole," said C. Darren Dowell, a scientist at NASA's Jet Propulsion Laboratory and lead author of the study, in a statement from the NASA. "This could explain why our black hole is silent while others are active. [9 Weird Facts About Black Holes]
Once things fall beyond the event horizon of a black hole, they are functional forever. The space beyond the event horizon is, from our point of view, really dark. There is nothing to see there. But as the Event Horizon telescope of the supermassive black hole of the Virgin One galaxy shows this spring, the horizon of events around a black hole is often surrounded by clouds of falling material. And this material moves so quickly and creates so much friction that it shines, creating light that allows astronomers to see Earth.
Some supermassive black holes put on these kinds of light shows all the time. But Sagittarius A * is one of the most common supermassive black holes. The structure does not seem to engulf a lot of material. And the Dowell team suspects that these intense magnetic fields could be the reason.
To map the magnetic field lines, a team of researchers pointed to a NASA infrared telescope called SOFIA – mounted at the back of a Boeing 747 – at Sagittarius A *. They have not yet officially released their findings, but the researchers presented their findings at the June meeting of the American Astronomical Society and described them in the NASA statement. SOFIA could not see the invisible lines, of course, but he could see the dust particles floating through these lines. And the structure of the magnetic field caused all the particles to point in one direction. These aligned particles in turn polarized the infrared light passing through the dust – in the same way that the sunglasses can polarize the light that passed through it – allowing researchers to determine where the lines were and where they were pointing.
Astronomers not involved in the research said the measurement of the magnetic field lines was exciting, but were skeptical that these lines fully accounted for the silent state of the black hole. (Everyone also noted that it was difficult to fully evaluate the work before the publication of the document.)
Erin Bonning, astrophysicist and black hole researcher at Emory University who did not participate in the work of SOFIA, pointed out that the image of the magnetic field lines corresponds to about 10 light-years , where 1 light year equals 93 million miles. (150 million kilometers). It's much wider than Sagittarius A * – an object that could enter our solar system – and is therefore too big to capture details in close proximity to the black hole. This smaller and closer region, she says, is where you expect the most important events that strike a material in a black hole – or hold it at bay – unfold.
"The press release seems to suggest that the magnetic field is directing the material into an orbit that" misses "the black hole.This would be a plausible explanation for the lack of strong accumulation on Sgr A *", writes Bonning in an e-mail to Science Live. .
However, she stressed, you would not necessarily expect materials to fall into a black hole, even without a magnetic field. Most supermassive black holes fail to absorb so many materials – perhaps because they are largely accumulated in the accretion disk orbiting the dark cosmic beast – and remain quite silent .
"You can see it this way: As massive as Sgr A * is, it is a physically * tiny * target with astronomical scales, so that matter falls in the vicinity of the event horizon, it has to move more or less directly to her, "said Bonning.
This happens most often in galaxies that have recently experienced violent mergers, she said. But the Milky Way has not experienced such a recent meltdown.
"If you have magnetic fields structured at light-years away from the black hole powerful enough to direct the movement of the gas, it may be that it's an additional mechanism preventing the material from penetrating in the galactic centers, "said Bonning.
But that does not mean that the magnetic field is the main mechanism that keeps the black hole silent.
Misty Bentz, an astrophysicist at Georgia State University, who was not involved in research, pointed out that while magnetic fields play an important role in maintaining the tranquility of Sagittarius A *, this does not mean that Similar forces work around a silent supermassif. black holes in other galaxies.
"Our galaxy is a bit special because our location inside it allows us to study many properties and regions in great detail," she said. "However, other galaxies are usually too far away to reach the same level of resolution and detail, especially when we talk about overcrowded environments in their galactic centers."
And what is true in the Milky Way might not be elsewhere.
"There could be a variety of reasons why other black holes do not feed, including shock waves and supernova explosions that expel gas from the center of the galaxy, or there could simply be a general lack of gas in the center of the galaxy, "Bentz said.
Simeon Bird, an astrophysicist from the University of California, Riverside, who also did not participate in the research, told Live Science that "magnetic fields can certainly help explain why some black holes are at rest and other assets ", but as Bentz points out. "All other supermassive black holes are far farther away, so it's hard to measure the magnetic fields around them."
Like Bentz, Bird is interested in other explanations for which black holes are silent. [5 Reasons We May Live in a Multiverse]
"Another possibility that could help keep the black holes at rest is that during an active phase, the black hole heats the gas around it to the point of completely disrupting it," he said. he declares. "If the black hole is very active, the energy of the black hole might just be able to completely eliminate the gas, get it out of the galaxy."
And once that happens, that black hole will probably disappear.
Nevertheless, despite some skepticism that the magnetic field lines could fully explain why Sagittarius A * is so silent – or that other supermassive black holes are silent for the same reason – Bonning, Bentz and Bird have qualified the important study, claiming that it proposes new keys to unlock the mysteries of supermassive black hole behaviors.
"Each discovery, such as the role of magnetic fields around Sagittarius A *, contributes to providing a piece of the puzzle and, with enough puzzle pieces, we can hope to understand the life cycle of the galaxies and the black holes that we have. they are hosting, "said Bentz. I said.
Originally published on Science live.
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