Story about the original black hole

Deng Shuxia and Gou Lijun compiled from Ian Randall. Physics World, 2022, (5): 33

This article is selected from "Physics", No. 6, 2022

The idea that the black hole may be formed shortly after the Big Bang can be traced back to 1966. At that time, physicists Yakov Zel ’Dovich and Igor Novikov proposed the presence of black holes for the first time. By the mid -1970s, Stephen Hawking and his colleague Bernard Carr proposed and developed this concept.

Our current theory of the universe is not allowed to be created in the early universe. Instead, stars and galaxies were originally formed by early fluctuations in the universe. The formation of black holes is much later, and after the first batch of ancient stars died.

However, if the original black hole (Primordial Black Holes) really formed one second after the Big Bang, the situation will be different. Hawking and Carr believe that the formation of the original black hole may be the result of the fluctuation of the early cosmic density. In their models, areas with slightly higher quality in the universe may collapse by themselves to form these seed black holes. The two in 1974 wrote: "The existence of galaxies today means that the early universe must be uneven. Some areas may be compressed very closely, so that they have experienced gravity collapse, which causes black holes. "

Hawking and CARR predict that the size of the original black holes may have a variety of, from small to 10 μg to 10,000 solar quality. This is very different from the black hole formed by the star. It is often between 5 and 10 solar quality and is limited by collapse to form their star size.

In the 1990s, the development of the expansion theory of the universe finally explained where the initial density fluctuations of the universe may come from. This concept has recently attracted people's attention because Ligo-Virgo first detected gravitational waves caused by the merger of double star black holes in 2016. The size of the black hole involved (within the range of 10-50 solar quality) is larger than expected, which allows some people to guess that the black hole originally originally originally originally originally originally originally originally originally originally originally originally originally originally originally served.

Since then, LIGO has now detected dozens of black holes. According to the results of the Bayesian analysis published by the University of Geneva at the University of Geneva Gabriele Franciolini and his colleagues last year, as many as 24 of these double -star black holes are likely to be formed in the early universe.

Black hole effect

In the standard model of the history of the universe, on the one hand, dark matter is still an unspeakable mystery. The original black hole was not part of it. On the other hand, if dark matter is mainly composed of black holes formed shortly after the Big Bang, then more stars and galaxies will be formed in the early universe. The James Weiba Space Telescope (JWST), which was launched last year, will focus on this era when studying the formation of early galaxies and stars. If the original black hole exists, the laser interference instrument space antenna (LISA) will be launched in the 1930s, it will be able to extract gravitational wave signals from the early merger of the original black hole to provide us with more evidence.

long, long ago

A study by Yale University's Priyamvada Natarajan and his colleagues further promoted the idea of ​​"the original black hole is really dark material in the universe". They proposed that if most of the original black holes were formed by the quality of about 1.4 times the solar, they could explain all dark matter in the universe. The model shows that these original black holes can provide gravitational anchors, and the first batch of stars and galaxies are formed around these original black holes. In fact, according to the team, these early black holes may have consumed the stars and gases near them, making them the predecessor of the large quality black hole in the center of the galaxy.

"If the original black hole does exist, they are likely to be the seeds formed by all the large quality black holes, including the center of the galaxy. I personally think that this idea is very exciting because it cleverly puts me two that I am studying. Really challenging issues (the nature of dark matter with the formation and growth of black holes) is perfectly combined and solved them in one fell swoop. "

The existence of the original black hole may also solve another long -term cosmic problem, that is, a variety of weak and distant infrared radiation detected by astronomers detected by astronomers. According to the NataRajan team, their models are perfectly predicted that because of material accumulation, the growth of the original black hole will produce exactly the same radiation characteristics.

Closer to home

Considering that the original black hole may exist in the universe, how likely it is to hit the earth. What will happen if it really happens? SOHRAB RAHVAR of Sharif University of Science and Technology in Iran assumes that the original Black Hole can explain all the dark matter in the galaxy and all dark matter in the dark disk. He calculated that the earth would collide with a original black hole with a mass of 1012 kg every 1 billion years. He explained that this is within the current life expectancy of the universe and the possible survival of the original black hole that may survive after Hawking's radiation evaporation (any original black hole with a quality of less than 1011 kg shortly after the Big Bang's Big Bang is now already in the original black hole in the original black hole of 1011 kg. Evolved). Although the larger black hole may still exist, the probability of colliding with the earth is not encountered in the entire life cycle of our earth. "When the earth is passing through the dark silver halo, it can attract the original black hole." Rahvar said. As he pointed out, the original black hole would pass through the earth, because its kinetic energy was too high and could not be trapped inside. Due to the dynamic friction of the gravitational interaction with the planetary material, and the amount of dynamic transfers generated by the material to the black hole, the original black hole will be slowed down.

As a result, people can imagine two possible results about the collision between black holes and the earth. One possibility is that it will cross the other side of the earth and to the other side of the earth, and in this process, it will transfer some of its energy. Another possibility is that the speed of the black hole will become so slow, so that it will fall to the core of the planet. Rahvar explained that at this time, the earth will be destined to perish. The accumulation of material in the black hole will heat the earth and keep the black holes growing continuously. In the end, the entire earth will be swallowed by black holes.

Fortunately, his calculation shows that if the original black hole did constitute the dark matter of our Milky Way, they will have such a high scattered speed (about 200 km/s), so that they can only fly to our home without the home, instead of not being able to fly, instead. Stop on the earth. Rahvar said: "We expect that there may be up to four primitive black holes in the life of the earth," he added. "Fortunately, even if a black hole is trapped inside the earth without the collision, The possibility is almost zero. "

The collision of space killer

Even if the original black hole does not destroy the earth, we may still want to know what happened when a original black hole whispered on our planet and whether it would leave any traces that we could detect as their existence. Considering this, RAHVAR calculated that the energy released by asteroids was actually five times that of the original black hole of the same quality. Even if their energy is equal, the possibility of black holes that cause the end of the world is far lower than asteroids.

However, RAHVAR continues to point out that the original black hole will have a significant impact on the local area. The passing of the original black hole may melt the cylindrical body with a radius of nearly 10 cm inside the earth. In a short period of time, this tunnel will be frozen. Theoretically, this will produce obvious deterioration fingerprints in the rock records. However, considering that there may only be 8 similar events in the life of the earth (every collision occurs on each side of the earth), RAHVAR admits, "I think such geological traces are difficult to detect."

Unlimited possibility, but fatal ending

The possibility of the earth was hit by the black hole in our lifetime, let alone a person, but it was never zero. So, what will happen if you are hit by the original black hole? Researchers have proposed that the original black hole with the size of the atomic size requires about 0.01 MS to pass through the human body. Although this process is very fast, the gravity effect of the original black hole can cause the human body to shrink a lot, cause severe damage and die immediately.

At the same time, Rahvar pointed out a different but also fatal result: the original black hole will burn the body on its path. "What will cause human death is not to directly devour the human body to the original black hole. The main reason for death is that the material is absorbed by the black hole to release many high -energy photons. These photons make the body burned."

With the completion of the preliminary research, Rahvar is now studying whether it is possible to use the space telescope to detect the original black hole in the galaxy, to use their microscopy effects on the prospecting stars. He explained: "With a space telescope such as Roman Space Telescope or James Wabo Telescope (JWST), we may soon detect or eliminate small quality of primitive black holes in the near future."

RAHVAR is also simulating how the original Black Hole interacted with Orte Cloud in the periphery of the solar system, and whether these tiny but huge celestial bodies can throw ice substances into the center of the solar system from the periphery.

Reprinted content only represents the author's point of view

Does not represent the position of the Institute of Physics of the Chinese Academy of Sciences

Source: China Physical Society Journal Network

Edit: fiufiu

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