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Space

Could a Faint Glow in the Milky Way Be Dark Matter? (space.com) 47

"A nearby galaxy once thought to be dominated by dark matter seems to have a surprise supermassive black hole at its centre," reports New Scientist.

Yet scientists "are convinced dark matter is out there," writes Space.com. "The quest to detect it arguably remains both one of the most frustrating and most exhilarating challenges in modern physics."

And now they report that the century-old mystery of dark matter — the invisible glue thought to hold galaxies together — "just got a modern clue." Scientists say they may be one step closer to confirming the existence of this elusive material, thanks to new simulations suggesting that a faint glow at the center of the Milky Way could be dark matter's long-sought signature. "It's very hard to actually prove, but it does seem likely," Moorits Muru of the Leibniz Institute for Astrophysics Potsdam in Germany, who led the new study, told Space.com...

The findings, show that dark matter near the Milky Way's center might not form a perfect sphere as scientists long thought. Instead, it appears flattened, almost egg-shaped, and that shape closely mirrors the pattern of mysterious gamma rays observed by NASA's Fermi Gamma-ray Space Telescope... Using powerful supercomputers, [the researchers] recreated how the Milky Way formed, including billions of years of violent collisions and mergers with smaller galaxies. Those violent events, the researchers found, left deep "fingerprints" on the way dark matter is distributed in the galactic core.... matching the pattern of gamma-ray emission Fermi has observed, the new study reports...

If the excess truly arises from dark matter collisions, it would mark the first indirect evidence that weakly interacting massive particles [WIMPs], a leading dark matter candidate, really exist...

"We have run dozens of direct detection experiments around the globe hunting for WIMPS," notes Phys.org, in an article titled "The Empty Search for Dark Matter." We have run dozens of direct detection experiments around the globe hunting for WIMPS — dark matter particles in this particular mass range. And they're not all the same kind of experiments. There are also the scintillators, which use a giant vat of liquefied noble gas, like several tons of xenon. They wait for a dark matter particle to strike the xenon and cause it to scintillate, which is a fancy science word for "sparkle." We see the sparkle; we detect dark matter...

They're just one example of a broader class of dark matter candidates, with delightful names like Q-balls, WIMPzillas, and sterile neutrinos. We've tuned our different experiments to capture different mass ranges or interaction strengths to cover as much of that wide dark matter spectrum as possible. We've even tried to manufacture various kinds of dark matter in our particle collider experiments.

And we've found nothing.

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Could a Faint Glow in the Milky Way Be Dark Matter?

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  • by denny_deluxe ( 1693548 ) on Saturday November 01, 2025 @05:01PM (#65766638)
    It brings in the science grants, at least.
    • How does paying to look for things that don't exist help taxpayers?? I'm all ears...
  • Nope (Score:5, Funny)

    by Big Hairy Gorilla ( 9839972 ) on Saturday November 01, 2025 @05:02PM (#65766640)
    If it glows, it's not dark.

    That's fairly easy to understand.
    • Beyonce has entered the chat.
    • There are unanswered questions now, as has always been. We are understanding more, like before relativity, we could not understand the orbit of Mercury. I don't think the answer is to make up some dark and mysterious magic to explain it, I think the answer is to refine our understanding of Gravity. My gut instinct tells me that the explanation as to why stars are orbiting black holes in galaxies has more to do with gravity waves than dark matter.
      • There are unanswered questions now, as has always been.

        For bonus points, try phrasing it as an actual sentence.

        • Grammar NAZI!! I think that language is made to express thoughts. Did I not express it well? Change the rules of grammar to fit my speak, and do not expect me to change my ideas to conform to grammar rules.
        • by cstacy ( 534252 )

          There are unanswered questions now, as has always been.

          For bonus points, try phrasing it as an actual sentence.

          "Could you phrase that as a question?"
          Mayim Bialik has left the room.

    • Re:Nope (Score:5, Insightful)

      by John.Banister ( 1291556 ) * on Saturday November 01, 2025 @06:46PM (#65766770) Homepage
      I completely agree with that concept. However, the reason for believing the dark matter is out there in the first place is on account of the effect of its mass. So if the dark matter isn't itself glowing, but its mass is re-routing light that had been traveling a different path into going on a path that causes us to see this glow, then it's not the dark matter that's glowing, but it is the dark matter that's causing (us to see) the glow.
    • Re:Nope (Score:5, Informative)

      by Waffle Iron ( 339739 ) on Saturday November 01, 2025 @07:36PM (#65766824)

      If it glows, it's not dark.

      That's fairly easy to understand.

      According to TFA, the dark matter isn't glowing. Instead, it is annihilating when it collides with another dark matter particle, which turns it into normal electrons and positrons, which then ionize normal gas and create the glow.

      It's a long sequence of events, but in case it pans out, at least it might be able to address the unwillingness of most people to accept that something could possibly exist unless it somehow interacts with the electromagnetic field.

      • I figured it was some kind of secondary effect, Thx for clarifying.

        I'm not a believer in dark matter exactly as much as it is a placeholder. I read that "they" found a shitton of matter in the inter galactic medium... uhhh... warm hot filaments .... iirc up to 40% of the missing matter. I wouldn't be surprised that there is just way more rocks and small cruft and brown dwarfs between the stars and we aren't measuring properly.
    • Re:Nope (Score:4, Insightful)

      by Mr. Dollar Ton ( 5495648 ) on Saturday November 01, 2025 @11:34PM (#65767012)

      If it makes things glow, but doesn't glow itself, it is still dark.

      There are experiments for example that look for dark matter particles (and it is pretty much settled that DM is particle-based, see https://en.wikipedia.org/wiki/... [wikipedia.org]) that can decay into a standard model particle-antiparticle, although with a very small likelihood.

      This isn't a far-fetched assumption if you accept that it is not unreasonable to suppose that some of what's unseen behaves by the same rules that what's seen does.

      So, what will a large pile of this dark matter appear like if distributed as observations suggest?

      Yes, it will make large areas around a galaxy glow faintly as those antiparticles annihilate.

      DNRTFA, but I guess it is something along these lines.

      • by cstacy ( 534252 )

        If it makes things glow, but doesn't glow itself, it is still dark.

        If a supermassive black hole takes a shit in the woods...

    • by Tablizer ( 95088 )

      > If it glows, it's not dark.

      Okay, but "Very very very very dim matter" is not very catchy.

  • by burtosis ( 1124179 ) on Saturday November 01, 2025 @07:23PM (#65766806)
    The nearby segue 1 is ultra diffuse with a few thousand stars and may be what we see as red dots early in the universe [youtube.com]. It’s studied precisely because it’s NOT like the vast majority of diffuse galaxies, it has 1000x the mass of dark matter per matter which is beyond the usual 100 to 1 ratio or less for diffuse and the reverse is true for normal galaxies like the Milky Way with a ratio closer to 10 or the cosmic average of 5 to 1. In short, it was studied specifically because it wasn’t like other diffuse galaxies, who have a large halo while calculations showed it must have dark matter tightly held at its center (not really possible as we understand it) or a black hole.
  • ...applies here.

    This is a speculation. If it were an actual finding, the headline would say "the Faint Glow IS Dark matter", not asking the question.

  • So "Dark Matter" is just black holes? Didn't we already KNOW that?

  • If you are trying to balance your books, and the numbers aren't adding up, you might suggest that there are mysterious kinds of transactions throwing things off, transactions that can't be seen or found through searches. But no accountant would accept that answer. Instead, they would look for missing or miscategorized transactions or incorrect calculations, or even fraud. All of those possibilities are a million times more likely than that some mysterious, untraceable "dark" transactions are throwing things

    • by dryeo ( 100693 )

      Look at the history of the neutrino, first postulated because the numbers for fusion weren't adding up so to balance the books was the idea of a dark particle (neutrinos do not interact with electromagnetism) with little or no mass came about. IIRC, it took about 30 years before a neutrino was detected as they do interact with the weak force (or is it the strong force, I get mixed up).
      Now it seems the universe is full of neutrinos and yet we can barely detect them.

  • by whitroth ( 9367 ) <whitroth@@@5-cent...us> on Monday November 03, 2025 @12:30PM (#65770106) Homepage

    No *possible* chance it's radiation created by infalling normal matter into the Milky Way's central black hole, right...

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