Astronomers have proposed a theoretical model suggesting that the object at the center of the Milky Way, widely identified as the supermassive black hole Sagittarius A*, could instead be explained by an extremely dense concentration of dark matter.
This idea challenges the longstanding explanation based on observations of fast-moving stars near the galactic core, which has traditionally been used to infer the existence of a black hole with a mass of about four million suns.
How can dark matter explain the center of the Milky Way without a black hole?
As the BBC reported, current research is focused on investigating the possibility that a smaller version of dark matter could create the same effect without the need for a singularity.
It will also be interesting to know whether such a configuration can explain the behavior of stars near the galactic center and the rotation of the Milky Way. Although the hypothesis is still under consideration, it opens another way to understand the gravitational effect of the object in question.According to this hypothesis, it would be possible to assume that dark matter composed of fermions would form an extremely dense core at the center of our Galaxy.
Meanwhile, the rest of the dark matter in this model will form a large halo around this center. Thus, the gravity of the dense body at the center of the galaxy explains the high velocities of the nearest stars.
A new theory links dark matter nuclei to fast-moving S stars
The study argues that the same dark matter composition could explain the motion of so-called S stars, which orbit near the galactic center at high speeds. These orbits have long been one of the main pieces of evidence supporting the black hole explanation.
The model is extended further by trying to match the Milky Way’s rotation curve, suggesting that the influence of dark matter could be continuous from the core outward rather than being restricted to a central body.
Comparison with black hole observations
Observations from instruments such as the Event Horizon Telescope have produced images of a bright ring surrounding a dark central region, which was previously interpreted as the shadow of a black hole. The dark matter hypothesis suggests that a similarly shaped feature could appear if light were strongly curved around a dense core.
From this point of view, the central darkness would not require an event horizon, but might instead result from gravitational lensing effects produced by the concentrated dark matter.If this hypothesis gets further support from more results, it means there may be a new explanation for the structure of the galaxy. Instead of a single black hole at its center, the core of the Milky Way can be considered the densest region within a broader distribution of dark matter. Thus, galactic mechanics must take into account the continuous distribution of mass from the center to the halo.
