What is a black hole? In a new scientific article, philosopher Erik Curiel at the Ludwig-Maximilian University in Munich, Germany, shows that physicists use different definitions of this concept, depending on the scientific field in which they work.
Usually, an astronomical object is called a black hole, which irreversibly absorbs all matter and radiation that falls within its sphere of influence. From the point of view of physics, a black hole is determined by the presence of a singularity, that is, a region of space beyond the "event horizon", inside which the mass-energy density becomes infinite, and the usual laws of physics cease to be fulfilled. However, as shown in a new article by Couriel, no one has yet formulated an exact and generally accepted definition of this "singular" state. Kuriel himself describes the problem as follows: “The properties of black holes are studied within the framework of various subsections of physics - in optical physics, in quantum physics and, of course, in astrophysics. However, each of these scientific disciplines has its own view of the properties of black holes, based on a certain set of theoretical concepts."
In carrying out this analysis, Couriel spoke to many prominent scientists to hear directly from them the definition of a black hole.
For astrophysicist Avi Loeb, "a black hole is a 'prison with no way out' - once you get inside, you can't get out." On the other hand, theoretical physicist Domenico Giulini believes that "conceptually considering black holes as cosmic objects that can move and experience the action of other objects, faces significant difficulties."
Couiel himself believes that the wide variety of definitions of a black hole is a positive point, since it allows physicists to simultaneously cover a large number of aspects of this phenomenon. However, in order to use this variety of definitions with maximum efficiency, it is necessary to identify the differences between them as accurately as possible.
The study is published in the journal Nature Astronomy.