- A study proposes dark matter, not a black hole, at the Milky Way's centre
- The dark matter core model explains star motion and galaxy rotation together
- Sagittarius A has long been considered a black hole with four million solar masses
A new study has proposed a surprising idea about the centre of our galaxy, challenging the long-held belief that a supermassive black hole exists there. Researchers suggest that a dense concentration of dark matter could instead be responsible for the same gravitational effects observed in the Milky Way, reported BBC.
The study, published in Monthly Notices of the Royal Astronomical Society, states that an ultra-compact dark matter core could explain both the fast movement of stars near the centre of the galaxy and the overall rotation of the Milky Way.
For many years, scientists have believed that the object named Sagittarius A is a black hole with a mass approximately four million times that of the Sun. This assumption is based on studies of nearby stars called S-stars, which orbit it at extremely high speeds.
New Alternative Model
However, a team of international scientists has now proposed a different approach. They have proposed a model based on fermionic dark matter, which is able to explain similar star motions even without a black hole.
According to co-author Dr. Carlos Arguelles, this is the first time a dark matter model has been able to simultaneously explain both the galaxy's large-scale rotation and the motion of stars near its centre.
He also clarified that this is not simply an alternative to a black hole, but rather suggests that the galaxy's core and its dark matter halo may be different forms of the same substance.
According to researchers, this dark matter, composed of fermions, could form a dense core surrounded by a diffuse halo. This dense core could generate such powerful gravity that it could produce a black hole-like effect, affecting the orbits of nearby stars and even bending light.
This bending of light could create a dark core surrounded by a bright ring, as seen in an image taken by the Event Horizon Telescope in 2022.
Lead author Valentina Crespi explained that this dense dark matter core could bend light so strongly that it creates a dark region in the centre and a bright ring around it.
Impact On Understanding Galaxies
If this theory proves correct, it could change our current understanding of how galaxies form. Instead of a black hole, the Milky Way could possibly be composed of a continuous structure of dark matter extending from its centre to its outer edges.
These findings open new dimensions to understanding the nature of dark matter and the structure of galaxies.
