{"id":652884,"date":"2026-06-22T21:39:31","date_gmt":"2026-06-22T21:39:31","guid":{"rendered":"https:\/\/www.newsbeep.com\/uk\/652884\/"},"modified":"2026-06-22T21:39:31","modified_gmt":"2026-06-22T21:39:31","slug":"scientists-thought-they-knew-whats-lurking-at-the-centre-of-our-galaxy-but-they-may-have-been-completely-wrong-this-whole-time","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/uk\/652884\/","title":{"rendered":"Scientists thought they knew what’s lurking at the centre of our Galaxy. But they may have been completely wrong this whole time"},"content":{"rendered":"

Stare to the south in the summer months and the constellation Sagittarius sits resplendent.<\/p>\n

Its meandering stars take on various shapes, including a teapot<\/a> and spoon.<\/p>\n

Just next to the teapot, close to where steam would rise from its spout, is the Galactic centre \u2013 the heart of the Milky Way.<\/p>\n

The Sun and every star you can see in the night sky<\/a> belongs to this sprawling stellar metropolis.<\/p>\n

\"AnAn image of the supermassive black hole at the centre of the Milky Way, captured by the MeerKAT radio telescope. Credit: NASA, ESA, CSA, STScI, SARAO, Samuel Crowe (UVA), John Bally (CU), Ruben Fedriani (IAA-CSIC), Ian Heywood (Oxford)<\/p>\n

\"constellationThe constellation Sagittarius and its Teapot star pattern<\/p>\n

A population of hundreds of billions of stars swirl around this central mass, like planets circle the Sun.<\/p>\n

For decades, astronomers felt confident they knew what it was that all these bodies were orbiting. A Nobel Prize has even been awarded for the discovery.<\/p>\n

But now, new research is calling the idea into question \u2013 and with it could come a deeper understanding of the Galaxy we call home.<\/p>\n

\"Sagittarius,Sagittarius, the Teapot and the band of our Milky Way captured by John Chumack, Cape Cod, MA, USA
\nLooking to the centre of our Galaxy<\/p>\n

The Milky Way stretches out like a dusty river either side of Sagittarius. This dust is so plentiful that it blocks our view of the Galactic core in visible light.<\/p>\n

If astronomers want to see what\u2019s going on there, they need to use longer wavelengths of light that can penetrate the dust.<\/p>\n

As far back as the 1950s, radio astronomers were picking up signals that suggested something interesting was happening in the heart of our Galaxy, but it took until the 1990s for them to begin peering through the dust with infrared telescopes built atop Hawaii\u2019s towering volcanoes.<\/p>\n

\"MilkyThe Milky Way over Slovakia, by Ondrej Kr\u00e1lik, Ve\u013ek\u00fd Man\u00edn, Pova\u017esk\u00e1 Bystrica, Slovakia, 12 April 2026<\/p>\n

“There are observations of stars orbiting around the centre of our Galaxy \u2013 the so-called S-stars \u2013 and from their motion we can infer there is a very massive and compact object there,” says Valentina Crespi from the Institute of Astrophysics La Plata in Argentina.<\/p>\n

From the orbital time and distance of these S-stars, astronomers could calculate the mass of this mysterious central object. It tipped the scales at a staggering four million Suns.<\/p>\n

And yet, for the stars to maintain their stable orbits and not be consumed, their gravitational master had to span less than a third the size of the Solar System.<\/p>\n

\"ThisArtist\u2019s impression of our galaxy, the Milky Way, based on data from ESA\u2019s Gaia space telescope. Credit: ESA\/Gaia\/DPAC, Stefan Payne-Wardenaar
\nThe supermassive-black-hole hypothesis<\/p>\n

At the time, the only explanation that fitted the bill was a supermassive black hole. Black holes<\/a> are usually formed by the deaths of massive stars, but no single star could fashion a monster as big as this.<\/p>\n

Instead, this black hole \u2013 dubbed Sagittarius A*<\/a> \u2013 was likely a fossil from the formation of our Galaxy.<\/p>\n

Merger upon merger stacked up smaller galaxies to build our grand spiral home, and each of these dwarf galaxies may have had their own, smaller black hole.<\/p>\n

Eventually, all these behemoths combined to create one central giant.\u00a0<\/p>\n

But while all this was going on, another mystery had been smouldering for nearly a century.<\/p>\n

\"CompositeComposite image of the Milky Way’s centre, using radio data from ALMA and X-ray data from Chandra. Credit: X-ray: NASA\/CXC\/UMass\/D. Wang et al.; radio: ALMA(ESO\/NAOJ\/NRAO)\/S. Longmore et al. Background: ESO\/D. Minniti et al.<\/p>\n

Ever since the 1930s, there was an inconsistency in the orbits of the stars much farther out into the Galaxy.<\/p>\n

Stars in the outer regions are moving too fast for the visible matter alone to hold them,” explains Carlos Arg\u00fcelles, also from the Institute of Astrophysics La Plata.<\/p>\n

Initially, the Milky Way seemed like a giant version of the Solar System. Sagittarius A* was like the Sun, the stars akin to planets spinning around it.<\/p>\n

Except the stars didn\u2019t appear to obey the same rules as the planets. In our Solar System, the farther a planet is from the Sun, the slower it orbits.<\/p>\n

Mercury, the closest planet, takes a fleet-footed 88 days to complete a lap of the Sun. Neptune, on the other hand, takes a tortoise-like 165 years.<\/p>\n

When astronomers began measuring the speed of stars in the vicinity of the Sun and farther out towards the edge of the Galaxy, they appeared to be moving at similar speeds to the stars much closer in.<\/p>\n

In fact, they were moving so fast that they should be able to escape from the Galaxy entirely and journey off into intergalactic space. Except they clearly weren\u2019t.<\/p>\n

\"TrailsTrails on an image of the Milky Way showing how 40,000 nearby stars will move across the sky in the next 400 thousand years. Credit: ESA\/Gaia\/DPAC; CC BY-SA 3.0 IGO. Acknowledgement: A. Brown, S. Jordan, T. Roegiers, X. Luri, E. Masana, T. Prusti and A. Moitinho
\nEnter dark matter<\/p>\n

This \u2018rotation problem\u2019 is usually explained by a mysterious substance called dark matter<\/a>.<\/p>\n

“Dark matter acts like an additional gravitational component,” says Arg\u00fcelles. “It\u2019s what keeps the stars in the outer regions bound to the Galaxy.”<\/p>\n

While most of the Galaxy\u2019s visible mass lies in its stars and gas, there\u2019s a swathe of invisible material scattered throughout the Galaxy, providing an additional gravitational glue.<\/p>\n

It was while thinking about this dark matter that a team led by Crespi and Arg\u00fcelles hit upon a radical new idea: what if Sagittarius A* is not a supermassive black hole at all, but instead another manifestation
of dark matter?<\/p>\n

“You don\u2019t need to put a black hole at the centre,” says Arg\u00fcelles. “Everything is part of the same substance.”<\/p>\n

This explanation rests on a particular type of dark matter known as \u2018fermionic\u2019 dark matter.<\/p>\n

\"SectionSection of a dark matter map created by the James Webb Space Telescope. Credit: NASA\/STScI\/J. DePasquale\/A. Pagan
\nTesting the theory<\/p>\n

For nearly 100 years, astronomers have searched for dark matter particles, but every effort has left them empty handed.<\/p>\n

That could be because dark matter particles are considerably lighter than they\u2019d bargained for.<\/p>\n

It\u2019s these lighter particles that Crespi and Arg\u00fcelles suggest could not only form a compact object at
the centre of our Galaxy, but also spread out into a more diffuse halo that would explain the rotation
of the rest of the stars in the Milky Way.<\/p>\n

Their model can match measurements of star speeds taken by the European Space Agency\u2019s highly precise Gaia spacecraft.<\/p>\n

Crucially, the dark matter idea is even consistent with the first-ever direct image of Sagittarius A*,
taken by the Event Horizon Telescope in 2022<\/a>.<\/p>\n

\"AstronomersAstronomers have captured the first ever image of Sagittarius A*, the supermassive black hole at the centre of our Galaxy. Credit: EHT Collaboration<\/p>\n

In reality, the image is not a direct photograph of the central object, but of the light around it.<\/p>\n

Hot gas spiralling toward the centre is heated to millions of degrees, causing it to glow.<\/p>\n

As this light passes close to the central mass, its path is bent by gravity, tracing out a ring-like structure.\u00a0<\/p>\n

The dark centre \u2013 the so-called \u2018shadow\u2019 \u2013 marks a region where light is either captured or deflected away from us.<\/p>\n

It is this interplay of glowing gas and warped light that gives photographs of black holes their characteristic appearance. But it\u2019s something that Crespi and Arg\u00fcelles can also explain.<\/p>\n

“The dark matter core produces an image with a central dark region and a surrounding ring of emission, very similar to what is expected from a black hole,” says Arg\u00fcelles.<\/p>\n

“Both scenarios can produce very similar observational signatures at the level we can currently measure,” adds Crespi.\u00a0<\/p>\n

\"ImageImage of supermassive black hole Sagittarius A* in polarised light, showing the direction of magnetic field lines. Credit: EHT Collaboration
\nOrbits will give the answer<\/p>\n

There are ways that astronomers could untangle the two possibilities, although they all require souped-up observations that we can\u2019t yet make.\u00a0<\/p>\n

“The key difference appears in the orbital precession,” says Crespi. “In a dark matter core, the stars would precess differently than around a black hole.”<\/p>\n

Precession is the gradual rotation of an orbit\u2019s orientation due to gravitational effects.\u00a0<\/p>\n

Using it to test the ‘black hole versus dark matter’ debate is a poetic echo of another dispute over a century ago, when the measured precession of Mercury\u2019s orbit around the Sun favoured Einstein\u2019s general theory of relativity over Isaac Newton\u2019s original theory of gravity<\/a>.<\/p>\n

Unfortunately, we don\u2019t yet have instruments capable of making precise enough observations of the orbits of S-stars, but there are facilities in progress that could do the trick.<\/p>\n

These include the GRAVITY+ upgrade already under way on the European Southern Observatory\u2019s Very Large Telescope Interferometer, and the Extremely Large Telescope, due to start operations in 2030.<\/p>\n

Arg\u00fcelles has also spoken to the team behind the Event Horizon Telescope about future upgrades there.<\/p>\n

“As the Event Horizon Telescope improves, with higher resolution and more observations, we expect to be able to distinguish between these scenarios,” he says.<\/p>\n

\"Artist'sArtist’s impression of the European Extremely Large Telescope in operation. Credit: ESO\/L. Cal\u00e7ada
\nWhat if they\u2019re right?<\/p>\n

While we wait for these tools to come online, what do other astronomers make of Crespi and Arg\u00fcelles\u2019 proposal?<\/p>\n

“It\u2019s an interesting idea,” says Harry Desmond, a senior research fellow in cosmology from the University of Portsmouth. “It would really pin down the microphysics of dark matter, which would be huge.”<\/p>\n

If the Milky Way isn\u2019t unique and other galaxies also lack supermassive black holes, the discovery would also force a major rethink on how galaxies work.<\/p>\n

“It would have a big knock-on effect on the energy budgets of galaxies, which are dominated by black hole feedback in the standard picture,” he adds.<\/p>\n

“Black holes could no longer quench star formation or regulate gas inflow across the Galaxy \u2013 some other mechanism would need to be found for that.”<\/p>\n

As always in science, extraordinary claims require extraordinary evidence.<\/p>\n

But if Crespi, Arg\u00fcelles and their team turn out to be right, we may need to dismantle some of the most fundamental assumptions in modern astrophysics.<\/p>\n","protected":false},"excerpt":{"rendered":"Stare to the south in the summer months and the constellation Sagittarius sits resplendent. Its meandering stars take…\n","protected":false},"author":2,"featured_media":652885,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[59,90,56,54,55],"class_list":["post-652884","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-gb","tag-science","tag-uk","tag-united-kingdom","tag-unitedkingdom"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/652884","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/comments?post=652884"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/652884\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media\/652885"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media?parent=652884"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/categories?post=652884"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/tags?post=652884"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}