5 ms·

Doesn't the bullet cluster provide strong evidence for the existence of dark matter? Shouldn't all alternatives need to explain the phenomenon seen there?

• deepnotderp 6y ago
  Iirc it provides evidence against most modified gravity theories, but other alternatives could theoretically still be viable.
• Fnords 6y ago
  It provides strong evidence of matter that we cannot detect. Milgrom's reply is worth a read: https://web.archive.org/web/20160721044735/http://www.astro.umd.edu/~ssm/mond/moti_bullet.html https://web.archive.org/web/20160721044735/http://www.astro....
  • haolez 6y ago
    Thus... dark matter?
    • artsyca 6y ago
      Isn't dark matter something like a shadow DOM.. It's there but also not there? Edit! Wow really feeling the love on this comment What I mean is dark matter is different from matter we just can't detect, it's matter that should be there but we can't seem to find it
      • BurningFrog 6y ago
        It's pretty simple: Dark Matter can't be seen or felt. It probably just travels through regular matter without "colliding", muchlike neutrinos. It only interacts with other matter through gravity. Now, we can detect gravity, but only for fairly big and stationary objects. If DM is tiny particles travelling fast, we can only detect aggregate effects on galaxy level.
        • artsyca 6y ago
          Yes just like we can't detect the shadow DOM from the DOM but it's really there you know? I feel like my thinking is too orthogonal any more. There's a difference between matter that's there which we can't detect as opposed to matter which isn't there which we can oh geez
          • BurningFrog 6y ago
            If you're making sense, I can't detect it :)
            • artsyca 6y ago
              Ever feel like you're too salty for your shirt? Can you appreciate the juktaposition of shadow DOM and dark matter or nah? I just post these comments so I can whittle my score back to zero and give you something to think about while you churn out features.
          • Rumudiez 6y ago
            Maybe it is similar in that the shadow DOM predicts the state of the actual DOM. In this interpretation dark matter predicts the shape of our universe. It might just be how one should go about simulating a universe..!
    • raverbashing 6y ago
      No. Because dark matter is understood mostly to be less interacting matter. Don't think it's a ball of dark stuff, think something you couldn't even see Whereas he's proposing regular (dark as in color) matter
      • balfirevic 6y ago
        > Whereas he's proposing regular (dark as in color) matter Wouldn't that kind of matter be easily detectable because it would block EM radiation, including visible light?
        • corty 6y ago
          Yes. "Dark" is misleading, it should be "sparsely-interacting" or something. Well, MACHOs would have been dark in the traditional sense as well. Generally, "we would have seen it" excludes a lot of dark matter candidates, thats what actually makes it "dark"
      • haolez 6y ago
        That's my understanding as well.
• nwallin 6y ago
  Yes, the bullet cluster effectively disproves most theories like MOND and similar. This article doesn't mention the bullet cluster. The article is dead on arrival as far as I'm concerned. Additionally, some galaxies have dramatically more or less dark matter than other galaxies. There's not a very good path forward for MOND-like theories with regards to explaining these galaxies. https://en.wikipedia.org/wiki/Ultra_diffuse_galaxy https://en.wikipedia.org/wiki/Ultra_diffuse_galaxy