We have written more than once about the ability of black holes to absorb almost any matter in the universe. However, recently, science has been able to discover a whole arsenal of other various features of these objects. It turns out that they are not only able to move at almost light speed and show signs of real space maniacs, destroying and devouring everything in their path, but also demonstrate significantly more flexible behavior than we are used to expecting from them. Today we'll talk about what else these objects are capable of.
Spin very fast
Scientists are the first to accurately measure the rotation speed of a supermassive black hole. It is amazing - 84 percent of the speed of light.
The black hole of the galaxy NGC 1365, located 60 million light years away, amazed researchers with its characteristics. Its diameter is 3.2 million kilometers, and its mass is approximately equal to several million solar masses.
As it rotates, it literally bends not only space, but also time behind it, creating a flaming whirlpool of X-rays, gas and dust falling into its bowels. All of this matter most likely falls into the black hole from one direction, which scientists believe gives it such an incredible rotational speed.
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Unite in groups
The largest galaxies discovered by astronomers are literally seeded with supermassive black holes. They are so huge that scientists doubt that single stars were their progenitors. Scientists have long suspected that supermassive black holes could be born in dense star clusters made up of groups of dying binaries or groups of more compact black holes that merge over time to form true supergiants.
Interestingly, the assumption has finally found real confirmation. X-ray analysis of the center of the Milky Way showed that in the very center of our galaxy there is a very dense region, in which there can be up to 12 black holes orbiting the main central black hole of the Milky Way - Sagittarius A *.
In addition, the analysis showed that a total of up to 20,000 black holes can be found in the central region of our galaxy.
Throw Jupiter-sized matter (sometimes in our direction)
Theoretical calculations and computer modeling suggest that near the central black hole of our galaxy - Sagittarius A * - there may be a very massive star, which every 10 thousand years approaches the hole very close, because of which the latter pulls out stellar matter from it, forming a long stream of incandescent matter. Part of this matter is devoured by the hole itself, while the other is thrown into space. However, some of this matter remains at a sufficiently distant distance from the hole and is capable of merging into a ball the size of a planet. But the most interesting thing is not even that.
These clubs of matter, in some cases the size of our Neptune, and sometimes as large as Jupiter, are thrown into galactic space at a speed of 3.2 - 32.2 million kilometers per hour. According to the calculations of the researchers, as a result of the events of tidal destruction of the star, about 100 million of these bodies will be thrown into space. And, perhaps, some of them will be directed in our direction.
Hide the galactic past
The Atacama Large Antenna Millimeter Array (ALMA) complex of radio telescopes allowed scientists to look for the first time at the core of a black hole - a collection of dust and gas orbiting a galactic monster's mouth and looking like a donut.
The object of study is located 47 million light-years away in the constellation Cetus. Thanks to the amazing power and sensitivity of ALMA, scientists have even calculated its width. It is about 20 light years old. By observing the tori of black holes, researchers can learn more about the past of galaxies. For example, an asymmetrical torus shape may indicate that a galaxy could merge with another galaxy at a certain period of its history in the past.
Absorb matter at incredible speed
A billion light-years away in the direction of the constellation Coma of Berenice is a very bright galaxy PG211 + 143. The galaxy owes its brightness to the central black hole, which absorbs matter from outer space at an incredible speed of 100,000 kilometers per second.
The researchers found that the X-ray emission from this galaxy exhibits a significant redshift, which can be explained by the movement of matter in this galaxy straight towards the central supermassive black hole at a tremendous speed of about 30 percent of the speed of light. This gas hardly revolves around the black hole, but moves directly to its center in a straight line, being incredibly close to the center of the black hole, which is only 20 times the size of a black hole.
Wander through space
Astronomers have long assumed that black holes can sometimes be ejected from their galaxies. And very strong evidence of this assumption, as it turned out, is located about 8 billion light-years from us. It is the quasar 3C 186, which has a mass of one billion solar.
Scientists have found that the quasar is striving at full steam to leave its native galaxy cluster. According to the calculations of the researchers, the gas cloud of the quasar is carried away at a speed of 7.6 million kilometers per hour. At this speed, for example, it will be possible to reach the Moon from the Earth in just 3 minutes.
Astronomers believe that the reason for this "escape" is gravitational waves - the product of the merger of two supermassive black holes. As a result of this merger, they created a powerful shock wave, comparable in strength to the simultaneous explosion of 100 million supernovae, which literally pushed the quasar out of its "home" place.
Stealing from larger relatives
At the moment, astronomers have not only confirmed five events of mergers of black holes and the gravitational waves produced by them, but also identified one of them that stands out against the general background. We are talking about the merger of two black holes, the mass of which, according to forecasts, should have been 10-15 solar. In fact, it turned out that the mass of both black holes exceeds 20 solar masses.
After analyzing the collected data, the scientists came to the conclusion that both black holes gained weight due to the fact that they stole "food" from a much larger black hole, which is also in the vicinity of the galactic center.
Before becoming black holes, these thieves were two massive stars. In the course of stellar evolution, they collapsed into black holes and began to be attracted to the galactic center, where there was already a supermassive black hole, absorbing the gas and dust surrounding it. The two "crumbs" managed to steal some of the matter from the central black hole and gained almost three times the mass of their original size before merging with each other.
Use magnetic fields for food
According to astronomers, one of the main factors determining the mass of a black hole may be its magnetic field. While exploring the Cygnus A galaxy, located 600 million light-years away, scientists discovered a very strong magnetic field in its galactic center.
Further analysis showed that the black hole Cygnus A is very active. Scientists believe that it is the most powerful extragalactic source of radio emission in its constellation, which is created as a result of absorption of the surrounding matter by a hole. And in this case, the researchers say, its magnetic field takes an active part, which attracts matter to the torus of the black hole, and then to its very depths.
According to astronomers, the difference between active galaxies like Cygnus A and inactive galaxies like our Milky Way lies in the presence and absence of a magnetic field.
Hide in tiny galaxies
There are only 100 million stars in the Fornax UCD3 galaxy in the constellation Fornax. This is a real crumb compared to the same Milky Way, in which hundreds of billions of stars can presumably be located. The radius of the Fornax UCD3 galaxy is only some 300 light years. Despite its tiny size, the "ultra-compact dwarf" UCD3 is one of the densest galaxies in the universe.
At its center is a supermassive black hole with 3-5 million solar masses. It is almost as heavy as the Sagittarius A * black hole at the center of our Milky Way, which is about 150,000 light years across.
The discovery of the UCD3 black hole turned out to be only the fourth case of the discovery of supermassive black holes inside ultracompact galaxies. Astronomers estimate that the hole accounts for 4 percent of the galaxy's total mass. As a rule, in any other case, this share is only 0.3 percent.
Scientists suspect that earlier the galaxy UCD3 was even larger, but the close location with a larger galaxy deprived Fornax UCD3 of a large number of its stars, turning it into a dwarf.
Eat our Sun in two days
Astronomers have discovered a remarkably voracious black hole that was born about 12 billion years ago. The discovered quasar absorbs a mass equivalent to one solar every two days. Due to this appetite, the black hole grows so fast that its radiation is thousands of times brighter than that of an entire galaxy. The very same radiation occurs due to the heating of matter and gases that it absorbs.
Scientists have not yet figured out how the black hole from the "dark times" so quickly gained its mass, but they are well aware of its potential.
If this monster were in the center of our Milky Way, then its brightness would be 10 times higher than the brightness of the full moon in the sky. The object would be so bright that it would overshadow the light of more stars in the sky, and it would also kill us all with its X-rays.
Nikolay Khizhnyak