Hacker Newsnew | past | comments | ask | show | jobs | submitlogin

Hi Jeremy, always a fan of your work! Just a technical note since it falls under my domain of expertise (astronomy) -- the example about MOND described here should actually have choice (E) as the correct answer!


As it happens I dug into this question in some detail a couple of weeks ago when analysing the dataset, including carefully reading the wikipedia page which the question comes from. AFAICT both D and E are kinda correct, but E isn't quite right because MOND doesn't entirely "eliminate the observed missing baryonic mass", but rather just reduces it from a factor of 10 to 2.

Is that not correct? (Of course I fully accept your expertise in this matter and this is just my curiosity, not trying to tell you you're wrong!)


Fascinating! I dug into the Wikipedia article, which cites a Scholarpedia article; the LLM answer seems to originate from a reference to this sentence [1]:

> So, MOND reduces the discrepancy in clusters at these radii to only a factor of ∼2−3 (Sanders, 1999; Ettori, et al., 2019)

So I think you're right, and today I learned something! I also checked if Stacy McGaugh had weighed in on this particular subject, and it seemed like there is still an issue for clusters [2], although interestingly the issue isn't mentioned in his latest blog post that summarizes the strengths/weaknesses with MOND [3]. Anyway, thanks for humoring me for a bit.

[1] http://www.scholarpedia.org/article/The_MOND_paradigm_of_mod... [2] https://tritonstation.com/2021/02/05/the-fat-one-a-test-of-s... [3] https://tritonstation.com/2023/06/27/checking-in-on-troubles...


I believe neither MOND nor Condensed Dark Matter are theories exactly, so much as they are schemata for classes of theories. Both are struggling to produce a verified theory that accounts for all observations, and while the latter is much more widely regarded as likely being correct, MOND has not been conclusively falsified to everyone's satisfaction. I would guess that there are, at least in principle, MOND theories which work for galaxy clusters but have residual discrepancies when applied to galaxies.

If this is so, then a multi-choice question which conflates one particular MOND theory for MOND itself, and which depends on the specifics of that particular theory for selecting the 'correct' answer, is problematic: for one thing, it may make selecting the 'correct' answer more difficult for a student who has specific knowledge about the topic. This is just one of several problems with multi-choice questions, though, fortunately, it does not seem to have any bearing on the very interesting phenomenon you have discovered.


In terms of the actual article -- really nice finding. Or I guess, nice set of experiments to decipher what lots of LLM researchers have been finding!

I've noticed somewhat similar behavior while training graph neural networks to model physical systems, except that it takes way longer than a single epoch to get there. Or course, there's no pretending involved with my GNNs, but the models do have very constrained representations, so once they start to figure out how to represent the physics at hand, the loss plummets dramatically.




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: