A team of astrophysicists has calculated that there must be more than 40 quintillion stellar-mass black holes in the observable universe. But even such an incredible number is only 1% of all typical matter.
Study was focused on stellar-mass black holes, the smallest of all options. It is noted that these calculations can help solve the mystery of how supermassive black holes are formed.
For decades, the existence of black holes was purely theoretical – not a single person could see them through a telescope. Because black holes absorb everything that crosses the event horizon, both matter and light. However, thanks to several projects in recent years, the existence of black holes has been confirmed by analyzing gravitational waves, and the first photo of the “shadow” black hole finally confirmed the theory.
But counting the number of black holes in the observable universe, which stretches over 90 billion years, is a completely different task. To arrive at a figure of 40 quintillion (that’s 40 and 18 zeros after), the team used the new stellar evolution code SVEN, along with data on the composition, formation frequency, and size of stars in known galaxies.
The current work is the first in a series of studies on mass modeling of black holes, from stellar size to supermassive. The mass of the first is usually several hundred times that of the Sun, and they are much more difficult to find than the supermassive ones located at the center of most galaxies.