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Cake day: July 1st, 2023

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  • If your view of string theory is through the lens of media, you aren’t going to be up-to-date. String theory was and is the leading theory for quantum gravity, is actively worked on, and has only been supported in recent findings through quantum field theory.

    But you’re talking about a field with little funding, that requires some of the most brilliant mathematical minds who have specializations, and in which experimentation requires super technology to build particle accelerators the size of the moon. It’s not a glamorous field and once the buzz of “theory of everything” wording died off, it was forgotten in media. Just like so many other topics before it.

    The standard model for quantum stuff

    The standard model doesn’t handle quantum gravity, which is kind of important. Nor does it address a slew of other very real phenomenon (dark matter, for instance). It’s not a theory of everything, just a good model. It’s also something that can be derived from string theory. The two are not competing ideas.


  • The scientific consensus seems to be that there isn’t really a good alternative to dark matter. Was it string theory that tried?

    The alternative to dark matter is modified gravity/modified Newtonian dynamics. Neither of which have held up to scrutiny and have major flaws that would need to be worked out before being a legitimate competitor to dark matter. In every single permutation thought of today, these theories directly conflict with the reality we observe, while dark matter has been in happy agreement with new data.

    that’s basically dismissed and disproven regardless of whether it had anything to do with dark matter.

    String theory is not disproven and still remains the leading train of thought. It’s just a very niche field and progress is hard/underfunded! But so far we’ve seen things like AdS/CFT correspondence and it’s a more “elegant” solution than its competitors.

    is there any reason to expect that the giant deep Antarctic ice-telescope will be able to observe dark matter?

    Are you talking about the IceCube? If so, no, that’s a neutrino telescope. Although, in general, the answer would also be no; dark matter does not interact with itself or with regular mass in any way other than through gravity. It’s simply impossible to measure it directly - it must be done by measuring it’s gravitational effect on other things.

    And because of that very property dark matter’s smallest observable structures are galactic in scale, so it’s also rather hopeless to try to observe them locally with current technology.




  • my understanding is that string theory is basically dead, and only getting deader.

    Huh… where is this impression from? String theory isn’t dead, it’s just a very narrow field in which most of the participants specialize in a subset of it that’s less concerned with completing it as a whole. It’s incredibly difficult work, progress is slow, and it’s currently too broad to be applicable to reality (which is important for funding). The tests we can think of to validate the correspondence of math to the physical world are… significantly out of reach due to the energy requirements.

    But it’s still the leading theory of quantum gravity and there’s active work in, say, AdS/CFT correspondence - which shows that string theory can line up to reality and be predictive. It’s the best idea we have right now, it’s satisfyingly elegant, and it’s working as a useful tool at the very least.

    There are competing alternatives that get their own research, of course. We should persue them all until a clear victor emerges!

    But I thought modified gravity as explanations for the dark matter observations is seeing a bit of a resurgence lately.

    Modified gravity, so far, is non-predictive and does not account for things like the bullet merger while also accounting for ultra diffuse galaxies and our observations of the CMBR. All proposed modified gravities have failed to pass experimentation compared to general relativity. Modified Newtonian Dynamics (MOND) fails in the face of light and gravity having the same speed. And even if MOND were to be true, it still requires the presence of (albeit possible baryonic) dark matter to be even considered due to existing mass measurements of galaxies.

    So, again, dark matter is simply the best model we have.



  • ThoughtGoblin@lemm.eeto196@lemmy.blahaj.zonenumber rule
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    1 year ago

    I’m not sure what you’re getting at. Dark matter has been proven numerous times, is a predictive model, and is the only explanation that has held up to scrutiny and observations. It’s very clearly the right explanation and we know how dark matter generally behaves, we just don’t know specifically what it is.

    See, for example, the behavior of the bullet cluster merger.