For a long time, it seemed that mysterious black holes existed exclusively in the minds of theoretical physicists. Now, thanks to the achievements of modern science, it has become clear: they really exist. On September 14, 2015, gravitational waves first oscillated space-time in American LIGO detectors. The proof of the ripples of space-time, predicted by Albert Einstein (1879–1955) 100 years earlier, is at the same time an experimental proof of the physical existence of black holes.
The first measured signal GW150914 arose from two black holes with 36 and 29 solar masses, which once surrounded each other in the form of a binary star system, until they finally merged into an object of 62 solar masses.
A few months later, the researchers recorded gravitational waves from the source GW151226 from a similar system. These events tremendously shocked the structure of space-time. And in an impressive way they confirmed the existence of this unknown cosmic monster.
But what is known to the common man about black holes? Just a few facts once learned in school astronomy classes. Let's try to compensate for this knowledge gap. Introducing the top 10 interesting facts about black holes in space.
10. Can be infinitely large
Super-sized black holes can reach from 105 to 1010 solar masses. It is still unclear how they arose and developed. Researchers suggest that there is a supermassive black hole in almost every center of the galaxy.
The black hole, which is located in the center of the Milky Way, also belongs to this category with 3.6 million solar masses. If a black hole is surrounded by a rotating gas-dust disk, then the matter may heat up and begin to glow very brightly. Such phenomena are called Seyfert galaxies or quasars.
9. They are barely noticeable
Black holes are hard to find because they do not emit light. Passing rays of light deviate from their orbit due to the enormous force of gravity. There are also black holes that “sleep” and become active only when matter approaches.
Since black holes absorb all of the light, as many shiny space objects in the sky do, astronomers cannot determine them directly. But there are a few keys that show the presence of a black hole.
On the one hand, the strong gravity of a black hole attracts any surrounding objects. Astronomers use these erratic movements to infer the presence of an invisible monster that is hiding nearby.
Or objects can revolve around a black hole, and astronomers can look for stars that don't seem to move at all to find a likely candidate for the title of black hole. So astronomers in the late 2000s identified Sagittarius A as a black hole.
8. Black holes - giant vacuum cleaners
Some scientists call black holes giant clusters of matter in a very small space. They also acknowledge that black holes act like a super-strong space vacuum cleaner.
They attract matter, and then mercilessly absorb it, like a carnivorous plant in a deep vent. They also catch stars when they fall into the attraction zone of such a black hole. In this case, stellar matter rotates around a black hole, heats up and glows brightly before disappearing into it.
In 2010, researchers observed with a telescope how a giant black hole literally tore a star.
7. Affect time
According to Einstein's Theory of Relativity, time for different observers proceeds differently. At speeds close to the speed of light, time flows more slowly for a moving body. That is, the speed of light is an absolute value, which is unrealistic to achieve, and time is always relative.
At one time, Einstein concluded that gravity appears as a result of the curvature of space-time. He called such a regularity the general theory of relativity. In curved space-time, all elements move along the shortest path.
The general theory of relativity suggests that the speed of time is directly dependent on the gravitational field.
Black holes have such a large mass that they bend space-time in such a way that a bottomless failure occurs in it. Therefore, once there, returning is already unrealistic.
6. Throw matter into space
Black holes are also a kind of omnivorous eaters, which often give out their location. When they attract surrounding stars, their powerful gravitational and magnetic forces overheat the incident gas and dust, causing them to radiate radiation. Part of this luminous matter encompasses a black hole in a swirling region called an accretion disk.
At the same time, matter that begins to fall into a black hole does not necessarily remain there. Black holes can sometimes throw falling stardustturning it into a kind of mighty radiation burps.
5. Not funnels, but spheres
In most astronomy textbooks and manuals, black holes are shown as funnels. This is because they are shown from the point of view of the gravitational well. In fact black holes resemble a sphere in their form.
4. Why are black
Despite the fact that the black hole has no matter, it has a surface - the “event horizon." In a sense, this is a limiter through which nothing can penetrate outward - neither a radio signal, nor even particles of light rotating at huge speeds. From here came the word "black".
3. The laws of physics do not apply in the center
If a black hole rotates, its event horizon is slightly deformed. However, the space-time of its immediate environment and the matter existing there rotate with it. This area of influence of the black hole is called the ergosphere and has the shape of an ellipsoid. Matter, which once entered it from the outside, does not necessarily plunge directly into the space-time trap, but first it rotates with it.
2. Not a single black hole is like the others
The supermassive black holes predicted by Einstein's general theory of relativity can have masses equal to billions of suns; these space monsters are probably hiding in the centers of most galaxies.
The Milky Way contains its supermassive black hole in the center, known as Sagittarius A, which is more than four million times more massive than our Sun.
The tiny members of the black hole family are still theoretical. These small whirlwinds of darkness could come to life soon after the Universe was formed as a result of a big bang, about 13.7 billion years ago, and then quickly evaporated.
Astronomers also suspect that there is a class of objects in the Universe called medium-sized black holes, although evidence of their existence is still controversial.
1. Opened by John Wheeler
John Archibald Wheeler coined the term “black hole” in 1967. Prior to this, the "father" of the theory of relativity Albert Einstein had already dealt with black holes. In his opinion, black holes are places of space-time that are so strongly bent that light cannot pass by without being absorbed.
In 1982, the first Big Hole outside our galaxy was discovered in the Great Magellanic Cloud, at a distance of about 150,000 light-years.