Galactic power stations: physicists have unveiled one of the major secrets of black holes.

Black holes can emit more energy into their surroundings than previously thought, and the faster they spin, the more efficiently energy extraction occurs. Astrophysicists have determined how disks of hot plasma rotating around black holes can become powerful engines for galactic power stations. The research has been published in The Astrophysical Journal, reports Space.

For a long time, physicists have proposed theories that energy is extracted from the rotation of black holes due to magnetic fields, directing it into powerful jets of high-energy particles that erupt from the poles of black holes. However, scientists were uncertain about many aspects of this process, such as what determines the amount of energy converted. Now, astrophysicists have modeled the action of the accretion disk around a supermassive black hole to obtain answers to these intriguing questions.

According to the authors of the study, it has long been known that matter falling into a black hole from an accretion disk made up of hot plasma can extract rotational energy from the black hole itself. This energy arises from the rotation of the object. It was believed that this energy is crucial for powering the jets of the black hole.

However, new modeling indicates that much more energy is extracted from black holes than previously known. This energy can manifest as light, causing areas near the event horizon of the black hole to glow.

Astrophysicists have been studying black holes and their interactions with their host galaxies for a long time, trying to understand how supermassive black holes at the centers of galaxies create active galactic nuclei and jets that shoot out at nearly the speed of light. Often, active galactic nuclei are so bright that they overshadow the combined light of every star in the galaxy, which requires a significant amount of energy that must come from somewhere.

Past research has shown that magnetic fields of black holes play an important role in this process. The authors of the new study aimed to understand how energy extraction occurs in these highly magnetized environments.

The new modeling by astrophysicists simulated the physics of hot plasma in the curved fabric of spacetime and the high-gravity regions surrounding black holes. This allowed scientists to observe how magnetic fields interact with black holes spinning at different speeds, particularly examining the efficiency of energy extraction.

The modeling revealed that between 10% and 70% of the energy extracted from the rotation of black holes was directed into their jets. The faster a black hole spins, the more energy it can release, according to the physicists. The remainder of the energy extracted from the black hole's rotation, but not directed into the jets, is either absorbed by the accretion disk or dissipated as heat.

Physicists also found that the strength of the magnetic field increased the brightness of the black hole's accretion disk. This may explain why some active galactic nuclei are much brighter than theoretical models predict.