Black holes are the scariest of all celestial bodies. Any matter close to it will be sucked in by its big black mouth, but there are still a lot of such celestial bodies in the universe. Some astronomers once thought that only in the Milky Way, there are 1 million to 100 million black holes. This number is quite astonishing. We can also say that there are a large number of black holes in the Milky Way. Fortunately, no black holes that are relatively close to the solar system have been found so far.
So how many black holes are there in the universe? Maybe many friends think about how to study this. It should be a mystery that will never be known. However, some scientists have conducted research in this area and estimated the approximate number of black holes in the observable universe. They believe that the number of black holes in the universe is about 400 billion.
This is really a scary value. The data come from a team of astronomical researchers at the International School of Advanced Studies (SISSA) in Italy, led by astrophysicist Alex Sicilia, who “combined detailed models of stellar and binary evolution Combined with advanced recipes for star formation and metal enrichment in individual galaxies”, including “black holes formed by single or binary evolution, and taking into account the role of black hole mergers, the number of which can be estimated from gravitational wave data, and produce slightly more massive black holes.”
Through these considerations, they calculated that the birth rate of stellar-mass black holes during the life cycle of the universe is 5 to 160 times the mass of the sun, and believe that in today’s observable universe, the total number of black holes may be as high as 400 billion.
The research team also compared their results with observed gravitational wave data and found that their estimates of black hole numbers and merger rates were in good agreement with the observed data. Relevant research has been published in the “Astrophysical Journal” in mid-January.
A black hole is a very magical celestial body, and its mass can be very huge. For example, the mass of the black hole Sagittarius A* in the center of the Milky Way is as high as 4.31 million times the mass of the sun, while the central black hole in the Andromeda galaxy, a neighbor of the Milky Way, is 100 million times that of the sun. The mass of the famous quasar Ton618 giant black hole is as high as 66 billion times that of the sun, but the largest black hole known so far is named SDSS J073739.96+384413.2, and its mass is 104 billion times that of the sun. This type of black hole is usually a galaxy or Center of gravity of giant type bodies.
In the universe, there are both giant black holes with huge masses and stellar black holes with a mass similar to the sun. At present, it is generally believed that the black hole with the smallest mass is more than 3 times the mass of the sun. Stars are formed through supernova explosions when they enter the final stage, but some stars with greater mass can directly collapse into black holes without going through the supernova explosion stage, and some black holes are formed by the collision of stars or neutron stars.
However, astronomers believe that there are still some primordial black holes in the universe. These black holes were formed shortly after the birth of the universe and were formed by the direct collapse of the extremely dense material regions in the universe at that time. The central black holes of galaxies and quasar black holes evolved from such primary black holes, but such black holes can also be very small, even much smaller than the earth, but these kinds of black holes are only theoretically believed to exist by astronomers, and they are not yet has been actually observed.
At present, the number of black holes observed and confirmed by scientists is less than 100. There is only one black hole that has been photographed by humans. It is the central black hole of M87, 55 million light-years away. To observe it, scientists use Eight huge radio telescopes scattered around the planet that have outlined an “Earth-sized” observing installation that has taken years to take and produce pictures of the black hole.
But in fact, what humans can see is only the accretion disk around the black hole, because the black hole itself does not emit light, so we cannot see it, we can only think that it is hidden in the middle of the orange-yellow accretion disk void part.