Researchers Propose 4 Million-Solar-Mass Dark Matter Core at Milky Way's Center

Q: What stellar wobble will new telescopes seek to reveal the true nature of our galaxy’s core?

The key “stellar wobble” is the tiny orbital precession of the Milky Way’s so-called S-stars, especially stars such as S2 that whip around Sagittarius A* at the Galactic Centre. Astronomers want to measure whether those stellar orbits rotate, or precess, in exactly the way general relativity predicts for a supermassive black hole, or whether they show a different pattern more consistent with a dense core of fermionic dark matter. In practice, this means tracking minute shifts in the stars’ closest approach, orbital shape and orientation over time. That is the decisive test because both models can reproduce much of what is already seen, including the roughly four-million-solar-mass concentration at the centre and even the ring-like appearance captured by the Event Horizon Telescope. What they should not produce is exactly the same long-term gravitational effect on nearby stellar orbits. New instruments are being built to detect that difference. The European Southern Observatory’s upgraded GRAVITY+ system on the Very Large Telescope Interferometer and the Extremely Large Telescope, expected around 2030, should deliver the astrometric precision needed to see this subtle wobble. If the measured precession matches the black hole prediction, Sagittarius A* remains the leading explanation. If it deviates in the way Crespi and Argüelles predict, the case for a compact dark-matter core would strengthen sharply.

3 articles · Updated · Sky at Night Magazine · Jun 22

Crespi and Argüelles argue the Milky Way’s center may be a compact fermionic dark matter core rather than Sagittarius A*, the supermassive black hole long inferred from S-star orbits.
Their model aims to explain both puzzles at once: the roughly 4 million-solar-mass object guiding stars near the Galactic center and the fast stellar rotation seen across the wider galaxy.
Gaia star-speed measurements and the Event Horizon Telescope’s 2022 ring-like image of Sagittarius A* are both consistent with the dark matter scenario, the researchers say, because current observations cannot cleanly separate it from a black hole.
The clearest test would be different orbital precession in S-stars, but instruments precise enough for that are still coming—through GRAVITY+, the Extremely Large Telescope due in 2030, and future Event Horizon Telescope upgrades.
If confirmed, the idea would reshape dark matter physics and force a broader rethink of how galaxies evolve, including the standard role of supermassive black holes in regulating gas inflow and star formation.

Sources

Sky at Night Magazine18h ago

Research Suggests Milky Way's Center is Fermionic Dark Matter, Not Supermassive Black Hole

The Daily Galaxy --Great Discoveries Channel18h ago

Astronomers May Need Over 35,000 Hidden Pulsars to Solve This Mysterious Milky Way Signal

YouTube18h ago

Sagittarius A Might Not Be a Black Hole After All

6 Sources

Could the Nobel Prize-winning black hole at our galaxy's heart actually be a dark matter imposter?

What stellar wobble will new telescopes seek to reveal the true nature of our galaxy’s core?

Dark Matter vs. Black Hole: The 2026 Fermionic Core Theory Challenging the Milky Way’s Center

Overview

A groundbreaking 2026 study challenges the traditional view that Sagittarius A* at the Milky Way’s center is a supermassive black hole. Instead, it proposes that Sgr A* is an ultra-dense core made of fermionic dark matter, surrounded by a diffuse halo of the same mysterious substance. This new model offers a unified explanation for puzzling galactic phenomena, such as the rapid, chaotic orbits of stars near the core and the galaxy’s overall rotation. By moving away from the black hole paradigm, the theory opens up fresh possibilities for understanding the true nature of our galaxy’s heart.

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