2023 Author: Bryan Walter | [email protected]. Last modified: 2023-05-21 22:24
Astrophysicist Priyamvada Natarjan creates schemes for the distribution of dark matter in space. In his book “Map of the Universe. The main ideas that explain the structure of the cosmos”she talks about the discoveries that made it possible in the twentieth century to understand the structure of the Universe, about the science behind them and the ways of recognizing radical scientific theories (the book is published in Russian translation by Arsen Khachoyan and Inna Cherkashina by the publishing house“Alpina non-fiction "This year). N + 1 publishes an excerpt in which Natarjan explores the history of the term "black hole" and explains how science predicted their existence long before the actual discovery of black holes.
Black CoreBlack holes become reality
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Black holes, the most massive and compact objects known to astronomy, provide abundant food for human imagination. As an example, I would like to note the series of Japanese manga drawings Inuyasha, created by the artist Rumiko Takahashi: their hero named Miroku carries on his hand the sign of curse received from his ancestor, under the influence of which everything he touches is instantly and mercilessly drawn into a certain tunnel of emptiness. Over time, this black hole grows, threatening to tighten and destroy Miroku himself. Such an ominous image of a mysterious object, absorbing and destroying everything in its path, has long become a generally accepted literary path and is applied to almost everything. In 2008, all American newspapers after the financial crash wrote about the "black hole" on Wall Street, and The New York Times almost constantly uses this image when describing a variety of events and situations - from the actions of terrorists and intelligence reports on the situation in the North Korea to the state of finances under Mitt Romney. In all cases, the concept of "black hole" implies a complete lack of information about any objects or circumstances.
As shown above, the recognition of some scientific ideas of the heliocentric model of the solar system or the theory of the expanding universe proceeded, as physicists say, nonlinearly. The same fate awaited the concept of black holes, which from an exotic mathematical concept turned into a generally accepted scientific theory and then into a popular object of modern culture.
It should be noted that initially the term "black hole" was not created at all to describe the special properties of astronomical objects, but originates from the history of a prison. On June 20, 1756, the nawab (ruler of Bengal) Siraj ud-Daula captured Calcutta, which had previously been held by the troops of the British East India Company under the command of John Holwell (who had proclaimed himself governor of Bengal). Nawab sent Holwell and other Europeans to solitary confinement in a prison built by the company itself. It was a very small chamber (6 m by 4 m and two tiny windows), popularly known as the "Black Hole." Nawab kept 146 prisoners in it without water and in a terrible stuffy atmosphere, of which only 23 people survived, after which the cell became notorious. Although scholars such as JG Little have questioned the accuracy of this information, the name of the prison - "Black Hole" - has survived, and it can be assumed that it remained in the subconscious and language as a grim metaphor of ruthless destruction. For example, when a terrible fire razed the Opéra-Comique in Paris on May 25, 1887, a New York Times correspondent briefly described the conflagration as "an enormous black hole."
Long before it was used in physics, the term "black hole" had become a well-established symbol of a dark dungeon in literature. In 1844, Edgar Poe published in the Philadelphia Dollar Newspaper the then famous horror story Buried Alive, describing the suffering of people buried alive. In the introduction to the story, the above-described tragedy in the Calcutta prison is again mentioned (Poe calls it "The Black Pit of Calcutta"). Even today, famous for his rich imagination, Thomas Pynchon repeatedly mentions "The Black Pit of Calcutta" in the popular musical drama "Mason and Dixon" (Mason and Dixon) as a symbol of horror.
Surprisingly, some of these literary examples very successfully described the nature of astrophysical objects that were not yet discovered at that time. In modern astronomy, they began to designate objects from which matter cannot escape. Trying to trace the origins of this concept and term, the historian of science Marcia Bartusyak notes that it was proposed and often used by the famous physicist John Archibald Wheeler. Apparently, he first used it in 1964 at the congress of the American Association for the Advancement of Science, after which the term took root in physics (and in general in modern culture), although Wheeler himself never claimed authorship.
We now know that black holes are located at the centers of most (if not all) of the known galaxies, including our own Milky Way Galaxy, in the center of which a giant black hole was discovered, the mass of which exceeds the mass of our Sun by about 4 million times. In distant space, glowing falling gas is drawn into active, growing black holes under the influence of a powerful gravitational attraction and gradually turns into visible quasars, which are the brightest "beacons" of the early Universe. Quasars become visible when the universe reaches about 1% of its lifetime. Based on a fairly detailed study of neighboring galaxies, we already know that monstrous black holes are often hidden in their centers, which reveal themselves only by gravitational effects on the stars and the inner regions of the surrounding galaxies. Fortunately, our solar system is located so far from the black hole in the center of the Milky Way that we can ignore this effect.
Currently, astronomers are confident that black holes (despite their extraordinary properties) arise as a result of ordinary physical processes that occur during the evolution of stars. The theory of stellar evolution suggests that hydrogen is the fuel for stars 15–20 times the mass of our Sun. After the hydrogen burns out, these stars end their lives as black holes. Black holes may have exotic properties, but they are an important component of the universe, playing a significant role in the formation and evolution of galaxies.
Let's now look at black holes from the point where the term ceased to be an object of the imagination and turned into an object that can be detected and described. The history of the term is associated with the "ivory tower" (in American English it is used to refer to academic circles. - Approx. Scientific. Ed.) - University of Cambridge in England in the XVIII century. Cambridge and Oxford were closely associated with the Church of England, and most of the students came from the nobility and the clergy. Upon graduation, they all signed the official 39-article "Creed" of the Anglican Church (the so-called "Thirty-Nine Articles of Anglican Faith"), so it should come as no surprise that many of the alumni later tied their fate with the church. One of the brilliant graduates of Oxford was able to imagine and describe completely unusual celestial bodies, namely, stars so massive that their light simply cannot leave the star that gave birth to it.
When in 1783 the English country priest John Michell first proposed the idea of the existence of some dark stars, he, of course, could not even imagine that we would ever be able to observe and register them. Michell himself was a polymath (this word then denoted talented scientists involved in several areas of science at once). He was born in 1724 and studied at Cambridge, where he later taught languages (Hebrew and Greek), as well as mathematics and geology. Michell's portraits have not survived, but contemporaries described him as "a short, swarthy and fat man." He was ordained and received a parish at Thornhill near Leeds. Despite his religious duties, Michell was active in a wide variety of cutting-edge scientific research, and met and corresponded regularly with many of the leading scientists of his time (such as Benjamin Franklin and Henry Cavendish) and regularly discussed various issues with them. They had something to discuss. Michell's scientific activity covered the problems of terrestrial magnetism, the theory of wave propagation from an earthquake over the surface of the Earth, etc. It was for his work on seismology in 1760 that Michell was elected a member of the Royal Society, however, despite all his achievements in the field of natural philosophy, he was much less famous than many of his contemporaries, perhaps due to the inability to propagandize and disseminate scientific ideas.
Following Newton's postulates, Michell viewed light as a stream of tiny particles (corpuscles) and therefore believed that massive stars should exert the same gravitational effect on these particles as on other astronomical objects (for example, comets) that came near. Since the gravitational effect is directly proportional to the mass of the star, Michell further suggested that there could be extremely massive stars capable of completely stopping light. In a letter to Henry Cavendish dated November 27, 1783, he correctly guessed that such "dark stars" should be detected only by the gravitational effect that they can exert on the bodies around them. Michell published this idea (in fact, the definition of black holes in the framework of Newtonian mechanics of his time) in the journal Philosophical Transactions of the Royal Society of London. He was not alone in these theoretical constructs. Just 13 years later, a similar concept was proposed in his book Exposition du système du monde by the French mathematician Pierre-Simon Laplace, who came to the conclusion: “… it is possible that for this reason the largest luminous bodies remain invisible to us in the Universe". However, when Newton's corpuscular theory of light later lost its popularity (as a result of which the idea of "dark stars" was forgotten), Laplace completely threw out all references to this hypothesis from later editions of his book.
Another 150 years passed, and the concept of these astronomical objects resurrected within the framework of Einstein's general relativity. This theory grew out of a simpler idea. Back in 1905, Einstein published the special theory of relativity (STR), in which he postulated that no object can move at a speed exceeding the speed of light. The existence of limiting speed had very profound consequences for science. First of all, it was established that it was impossible to transmit a substance or information at a speed greater than the maximum possible. From this theory arose the famous formula for the equivalence of energy and mass, expressed by the now well-known formula E = mc2. However, in 1915, Einstein proposed general relativity, which profoundly changed our understanding of mass, gravity and space, which allowed the idea of black holes to revive. The mathematics of general relativity allows us to visualize the reality around us in a new way. As described in the previous chapter, the new theory gave rise to a new model of the universe, the first major revision of the worldview since Newton. At the same time, however, to the deep disappointment of Einstein himself, this theory admitted the existence of black holes.
At the risk of incurring accusations of distorting Einstein's light image, we should note that he opposed the concept of an expanding universe and hated the idea of black holes. This can be explained, by the way, by the following circumstance: the admiration of physicists with Einstein's works is connected, at least in part, with the fact that he managed to construct the great general relativity literally from nothing (ex nihilo), that is, without explaining any observed phenomena. This is as flawless as a physical theory can be. Therefore, general relativity evoked special respect as an example of demonstrating the power of speculative reasoning, allowing one to achieve a purely mathematical description of nature. His theory assumed a deep understanding of the nature of gravity - a mysterious force that holds together not only the solar system, but the universe as a whole. Throughout his scientific career, Einstein was guided by the desire to comprehend the unity and simplicity of the structure of the world. It was these philosophical beliefs that sometimes prevented him from perceiving and recognizing unusual results, even if they flowed from his own works and theories. This was also the case with black holes.
Einstein's theory was not only mathematically elegant and independent of observation, but made several important scientific, testable predictions. At the same time, the theory significantly outstripped the existing needs and the possibilities of its verification or application. In a sense, we can say that at the beginning of the last century, general relativity was a "sterile clean" area of physics, far from the mainstream of scientific research of the era. It was important for astronomy, but in astronomy it was not associated with real-life physical objects, at least at the very beginning of the last century. General relativity began to be used to describe the Universe (as a whole) already in the first decades after its creation. Since the observed effects predicted by the theory were very weak for astronomical objects with a small mass, the theory remained unused in observations until the discovery of new exotic objects in space (such as neutron stars, pulsars and quasars), in the description of which its rich capabilities were manifested. Thus, when in the early 1960s. astronomers discovered these superheavy objects in space, Einstein's theory was already sufficiently developed and developed to describe them.
Today, the most convincing evidence of the existence of black holes has been obtained for the spiral galaxy NGC4258, inside which there is a black hole, about 40 million times more massive than the Sun. To get a feel for scale, imagine that while mapping the interior of this galaxy in radio frequency range, astronomers discovered a disk that appears to be a reservoir of gas swirling into a black hole, so wide that it took light a year to cross it (unless there is gas captured by a black hole). It is these objects that control the movement of stars within galaxies. It is now assumed that the centers of the brightest galaxies are also home to supermassive black holes with masses billions of times the mass of the Sun.
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