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Triplet of 'ghostly' galaxies hints at what dark matter is and isn't

Triplet of 'ghostly' galaxies hints at what dark matter is and isn't

gumby

Comments (57)

  • blauditore
    For someone like me who doesn't know much about modern physics, dark matter has the vibe of a band-aid to me. Like a programmer who discovered that the algorithm was always off by 1 in the results, and just ended up returning r + 1 without thinking twice.I'd bet a large chocolate cake that one day, physicists will discover a much more logical explanation for this unexpected behavior of matter.
  • nemo136
    Idea for a science fiction short story: dark matter interacts with normal matter only in specific conditions requiring advanced science, with extremely rare occurrences naturally.Humanity, after migrating from biological carbon based substrate, finds ordinary matter not practical to live in. Dark matter has much better properties.All humanity transfers to dark matter where it finds all the other "ascended" species historically hosted by our universe. Solves Fermi's paradox and keeps the "normal matter" nursery clean for new species to appear.
  • janalsncm
    I don’t really understand. Dark matter is in most galaxies interacting gravitationally, but not these three. Their idea is that somehow there was a collision event which stripped the galaxies of their dark matter, because the regular matter got tangled up but dark matter somehow didn’t.But if dark matter is also interacting gravitationally, why wouldn’t it also be tangled up? And is that something we have seen in other collisions ever?
  • MattPalmer1086
    Also see [1], a follow up post by Stacy McGaugh, a MOND proponent, who is quoted in the Quanta article. He does not agree with the evidence as presented in that article.[1] https://tritonstation.com/2026/10/15/ghostly-galaxies-in-the...
  • Sniffnoy
    It bugs me that articles about dark matter so frequently frame things as dark matter vs. MOND, and don't consider any of the other theories of modified gravity. I think MOND is just not a great theory and it has a lot of evidence against it by this point; but other theories of modified gravity have not, to my knowledge, been tested to the same extent, nor do they get anywhere near the publicity. Dark matter still seems more likely than modified gravity, but I wish they wouldn't emphasize MOND so much as the representative of modified gravity, and I wish we'd hear more about tests of other modified gravity theories!
  • anon
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  • analog31
    I wonder if this means there are giant balls of dark matter hurtling around the universe.
  • potamic
    > If two typical galaxies met in a head-on collision, the dark matter would experience very little friction, or drag, and would keep on rocketing by. But ordinary matter, which interacts using all four fundamental forces, would get all tangled up.Isn't a galaxy mostly empty space? I thought I read before that when galaxies collide there's actually very little physical contact between the matter. Stars mostly pass through affected predominantly only by change in surrounding gravity. Is this not the case?
  • mac3n
  • miramba
    [dead]