Black holes cannot be seen, they are indicated by various indirect data. White holes opposite to them in properties exist only in theory. Scientists admit that they could perish during the development of the Universe or get lost among dark matter, becoming inaccessible for observation. What is known about these exotic sites.
White underside of a black hole
In the 1960s, the Soviet theoretical physicist Igor Novikov (ASC FIAN), proceeding from the theory of relativity, came to the conclusion that there should be objects in space with the opposite properties to black holes. He called them white holes.
Imagine a sphere of such a monstrous mass that you can only break away from its surface at the speed of light. This is a black hole. Its radius is called gravitational. If all of the Sun's material is compacted into a sphere with a radius of three kilometers, it will turn into a black hole.
The gravitational radius is also called the event horizon. If behind it, inside the sphere, an object falls, for example, a spaceship or a piece of stellar matter, then it will not return back. Huge gravitational forces will pull it into a black hole and there will tear it apart into elementary particles.
Atoms from a black hole fall into a white hole and instantly fly out of it, but in another universe. And they fly out of the future into the past. A white hole is a black hole reversed in time.
White holes are unstable. As matter forms in them, gravitational forces grow and at some point collapse the object, turning it into a black hole.
Promotional video:
Perhaps all the white holes that formed immediately after the Big Bang are now literally dead, so we can't see them.
From a black hole in our universe, you can get into a white hole in another universe. The white hole that we can observe here is - this is a window from some third universe. / illustration RIA Novosti. Alina Polyanina, Depositphotos.
Pimple on the body of the universe
In modern cosmology, a white hole performs an important function - without it, the birth of universes is impossible. In the late 1980s, American physicist Alan Guth, one of the authors of the theory of inflation, modeled the process of the birth of a new world within the old universe.
Let's say a singularity occurs in space (an area with a very high density of matter and curvature of space). Its explosion and rapid expansion (inflation) begins with a white hole crushing space-time in the strongest way.
The white hole grows like a pimple on the body, and eventually separates from the mother's universe, leaving a scar in the form of a black hole. In the newborn world, a "navel" appears accordingly. Birthing scars in both universes will quickly heal thanks to Hawking radiation.
Until the new world is isolated, one can observe its birth and formation inside stars and galaxies. It is possible that our Universe also took place in this way inside some other universe.
Where to look for white holes
Quasars - the brightest space objects in space and active galactic nuclei - were tried on for the role of white holes. In 2011, Israeli scientists Alon Retter and Shlomo Heller suggested that white holes are spontaneously born in space and, throwing out all the matter at once, die. They cannot be regarded as cosmic bodies; rather, they are “windows” in the Universe, living for only a few minutes. It is impossible to predict the time and place of birth of white holes.
Most of all for the role of such spontaneous "windows", according to Retter and Heller, gamma-ray bursts are suitable, which are the strongest explosions with the radiation of high-energy particles, which lasts two seconds or more. Their traces are observed in different regions of the Universe for many billions of light years from us. If a gamma-ray burst happened nearby, life on Earth would be quickly destroyed.
In June 2006, the orbiting observatory recorded an unusual gamma-ray burst in the constellation Indus at a distance of two billion light years - it was assigned the number GRB 060614. It was distinguished by a long duration - 102 seconds, and a supernova capable of causing it was not found nearby. Retter and Heller hypothesized that GRB 060614 is a white hole.
The X-ray image of GRB 060614 was taken by the Swift orbiting telescope in June 2006.
In the depths of dark matter
According to theoretical physicists Carlo Rovelli from France and Francesca Vidotto from Spain, most of the dark matter may consist of white holes.
They revisited the thirty-year-old astrophysicist Jane McGibbon's hypothesis that dark matter was left over from evaporated black holes, and concluded that these were white holes.
We are talking about primordial black holes that formed immediately after the Big Bang. Over the 13.7 billion years of the existence of the Universe, matter has gradually leaked out of them in the form of Hawking radiation. Having reached the Planck size (about 10-35 meters), they turned into white holes.
Unlike normal-sized white holes, microscopic ones can be stable, since on micro-scales quantum processes prevail over gravitational ones.
Dark matter occupies about a quarter of the universe and is concentrated inside galaxies. It does not manifest itself in any way, does not radiate and interacts with ordinary matter only gravitationally.
Tatiana Pichugina