Scientists suggest that our galaxy may be driven by a mysterious large clump of dark matter, rather than a supermassive black hole.
While it was previously widely believed that the Milky Way has a supermassive black hole at its core and a scattered "halo" of dark matter, researchers are now proposing an alternative theory.
The enormous gravity of a black hole would explain the orbits of so-called S stars, which revolve around the nucleus at speeds of several thousand kilometers per second. Meanwhile, the slight pull of the dark matter ring explains why the galaxy's rotation does not slow down significantly towards the edges.
Researchers from the La Plata Institute of Astrophysics propose that our galaxy may orbit a large clump of dark matter. Dark matter is the invisible substance that is not seen by telescopes, but which is thought to make up over a quarter of the universe.
According to experts, a super-dense clump of dark matter could explain both the rapid motions of stars near the galactic core and the galaxy's gentle rotation on a large scale.
Dr. Carlos Argüelles, co-author of the study, says:
"We are not simply replacing the black hole with a dark object; we are proposing that the central supermassive object and the galaxy's dark matter halo are two manifestations of the same continuous substance."
The key to this surprising suggestion is a very specific form of dark matter made up of particles called fermions, extremely light subatomic particles. In theory, these particles could form a super-dense, compact core surrounded by a diffuse halo that acts as a single entity.
The dense core explains the rapid motion of S stars, while the outer halo can explain the larger motions of the galaxy.
Dr. Argüelles emphasizes: “This is the first time that a model of dark matter has successfully linked these very different scales and the orbits of different objects.”
One of the most important pieces of evidence for this theory is an image of the galactic nucleus taken by the Event Horizon Telescope in 2022, which showed a halo of light around something dark, believed to be the black hole Sagittarius A*.
According to the study by Argüelles and collaborators, light produced by matter orbiting a dense clump of dark matter creates an image very similar to that of the Event Horizon Telescope.
Valentina Crespi, lead author and PhD student at the La Plata Institute of Astrophysics, says:
“Our model explains the orbits of stars and the rotation of the galaxy, and is also compatible with the famous image of the ‘black hole shadow.’ The dense core of dark matter can mimic the shadow, distorting light and creating a central darkness surrounded by a bright ring.”
According to the researchers, current data on stars near the galactic core are compatible with both the black hole model and the dark matter model. However, they argue that the dark matter theory is preferable, as it explains the structure and behavior of the Milky Way with a single unified object.
In the future, more precise observations will be needed to determine with certainty what lies at the heart of the galaxy. For example, extremely sensitive instruments could detect “photon rings” – a hallmark of black holes that would be missing in the dark matter scenario. /GazetaExpress/
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