Center of a black hole
Pro Research Analysisby 
Searched over 200M research papers
Supermassive Black Hole at the Galactic Center: Mass, Structure, and Evidence
The center of our Milky Way galaxy hosts a supermassive black hole, known as Sagittarius A* (Sgr A*), with a mass of about 4 million times that of the Sun. This conclusion is supported by precise measurements of the orbits of stars very close to the center, which show that a massive, compact object must be present within a tiny region of space 1310. Observations from the Event Horizon Telescope have directly imaged a bright ring of emission around a dark interior, matching predictions for a black hole’s shadow and providing strong evidence for the existence of an event horizon at the center of Sgr A* .
The Nature of the Black Hole Center: Singularity, Event Horizon, and Theoretical Models
According to general relativity, the center of a classical black hole is a singularity—a point where density and gravity become infinite. However, direct observation of the singularity is impossible because it is hidden behind the event horizon, the boundary beyond which nothing can escape . Some theoretical models propose alternatives to the singularity, such as nonsingular black holes with regular centers, but these models often face stability issues and may require new physics beyond current theories 45. Other proposals suggest that the center may not contain a massive point at all, but rather a region dominated by vacuum energy or exotic matter, though these ideas remain speculative and are not supported by current observations .
Observational Evidence: Stellar Orbits and Accretion Disks
The strongest evidence for a supermassive black hole at the galactic center comes from tracking the motions of stars in the immediate vicinity of Sgr A*. These stars move at extremely high speeds, consistent with the gravitational pull of a massive, invisible object confined to a very small volume 13810. Additionally, observations have revealed a disk of hot and cooler gas orbiting close to the black hole, further supporting the presence of a deep gravitational well at the center .
Physical Properties: Mass, Spin, and Charge
The black hole at the center of the Milky Way is characterized by its mass, spin, and possibly electric charge. While the mass is well constrained by stellar dynamics, the spin and charge are less certain. Theoretical studies suggest that any electric charge is likely to be very small and transient, as the surrounding plasma would quickly neutralize it. However, even a small charge could affect the motion of charged particles near the event horizon .
The Environment Near the Center: Star Clusters and Accretion
Surrounding the black hole is a dense cluster of stars, including some that orbit extremely close to Sgr A*. Surprisingly, many of these stars are young, which is unexpected given the harsh environment near a supermassive black hole. This "paradox of youth" remains an open question in astrophysics 18. The accretion of gas onto the black hole produces variable emission across the electromagnetic spectrum, and recent high-resolution observations are beginning to reveal the structure of the accretion flow near the event horizon 1910.
Conclusion
The center of a black hole, as described by current physics, is a region hidden behind an event horizon, where matter collapses to a point of infinite density—a singularity. While alternative models exist, the best observational evidence supports the presence of a supermassive black hole with an event horizon at the center of our galaxy. The detailed nature of the very center remains a topic of theoretical investigation, but direct imaging and stellar dynamics provide compelling evidence for the existence of a true black hole at the heart of the Milky Way 1389+1 MORE.
Sources and full results
Most relevant research papers on this topic
Observations of stellar proper motions near the Galactic Centre
The proper motions of 39 stars near the Galactic Centre strongly support a central dark mass of 2.45 0.4 106 solar masses, suggesting a massive black hole is most likely occupying the central region.
Instability of Nonsingular Black Holes in Nonlinear Electrodynamics.
Nonsingular black holes in nonlinear electrodynamics are prone to instability around the center, suggesting that stable, regular centers require theories beyond nonlinear electrodynamics.
A cool accretion disk around the Galactic Centre black hole
This study reveals a 104-kelvin ionized gas disk around the Galactic Centre black hole, suggesting a rotating disk with a mass of 105 to 104 solar masses and mean hydrogen density of 105 to 106 per cubic centimeter.
First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way
The first Event Horizon Telescope observations confirm the presence of a supermassive black hole at the center of the Milky Way galaxy, supporting the theory of general relativity.
DOI