◎ Science and Technology Daily reporter Liu Xia
How many black holes are there in the universe? This is one of the most pressing questions in the field of modern astrophysics and cosmology, and scientists are now finally giving the answer! Scientists at the International Institute for Advanced Study (SISSA) and other institutions in Italy wrote in the latest issue of the Astrophysical Journal that they first counted the number of stellar-level black holes, calculated their distribution throughout the universe, and calculated that the number of black holes in the observable universe is currently about 400 billion.
Image source: Visual China
In the latest study, the scientists combined the empirical formula of the most advanced stellar and binary evolution algorithm developed by SISSA researcher Dr. Mario Sperra with the physical properties associated with galaxies (especially the rate of star formation, the number of stellar black holes, and the metal content of the interstellar medium) to develop a unique calculation method that led to the above conclusions.
Stellar-level black holes with masses ranging from a few to hundreds of solar masses stem from the end of massive star life, and the new study points out that about 1 percent of ordinary matter in the universe is "locked" inside stellar-level black holes.
The researchers explain: "The formation rate of stars and other properties are important elements that define the number and mass of stellar black holes, and with the help of the new calculation method, we have derived the number of stellar black holes and their mass distribution throughout the history of the universe, and based on this, the number of black holes in the entire observable universe." ”
Study lead author Dr Alex Cecilia commented: "The innovation of the latest study is the combination of detailed models of the evolution of stars and binary stars with properties such as star formation and metal content in individual galaxies, which is the first time scientists have calculated the number of stellar-level black holes and have come to the most solid conclusions to date. ”
In addition to estimating the number of black holes in the observable universe, the team also worked with scientists at the University of Padua to explore various ways for black holes of different masses to form, including isolated stars, binary star systems, and star clusters. The latest research suggests that the most massive stellar black holes are mainly derived from dynamic events in star clusters.
"This study covers all aspects of stellar astrophysics, galaxy formation and evolution, gravitational waves and multi-messenger astrophysics, laying a solid foundation for further study of stellar-level black holes and their origins," the researchers said. ”
Source: Science and Technology Daily
Editor: Liu Yiyang
Review: Wang Xiaolong
Final Judge: He Yi
![Astrophysicists calculate that there are about 40 billion stellar-sized black holes in the observable universe[fig]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)