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Comment by sega_sai | Hacker News Reader

(Astrophysist here). This is complete BS. (I can't comment on the theoretical aspects of gravitomagnetism, not my area of expertise) but the data part is a joke. They "fitted" the rotation curves of three galaxies with their very obscure model with a bunch of parameters. What does it prove -- nothing. Plus, if I understand their model correctly, their model will not work for systems without any rotation, i.e. dwarf spheroidals galaxies which do not rotate, but still have ~ 1000 more dark matter than visible matter (based on stellar velocity dispersion measurements). And the evidence for dark matter is there is not only in flat rotation curves, but in cosmic microwave background for example; as to explain the cosmic microwave background you must have a large fraction of DM in early universe.

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Not having even tried out applying relativistic gravitation to any galaxy at all, when the numbers seem to show a significant effect, is an enormous omission. Even if this doesn't wholly pan out, you and your colleagues have all failed at your job. Their failing in no way absolves you.

It is not necessary for the result to match observations in any but a sampling of galaxies. In particular, they don't need to explain any other phenomena than rotation curves. With those matched, it will be your and your colleagues' responsibility to show why those galaxies lack the dark matter all galaxies are supposed to have, and to explain how your cosmic background curves accommodate the painfully clear lack of sufficient expected dark matter.

The number of galaxies found to have no room for dark matter will only increase.

If your theory accommodates any random amount of dark matter equally well, that removes dark matter from the list of reasons to believe it, and makes having promoted that as a reason a fib.

Maybe you shouldn't assume that the scientists are all stupid, just because some rando wrote a blog post.

This 'result' isn't going to hold up.

Sadly, scientists are actually not so bright (those who are usually go to the industry or driven out by envious peers, academia is a poisonous swamp), but some of them are also narcissists, prone to have "pet theories" vulnerable to fashion and so on.

I'm scientist myself, but lucky enough to have other means to live, so I can do science (and I publish at a good rate) on my own accord.

The paper itself cites previous attempts of the “generations of cosmologists” to use models that do take relativistic gravitational effects, including gravitomagnetism. The common models aren’t Newtonian because nobody has tried anything else, they’re Newtonian because the previous relativistic models didn’t end up producing different results.

The model used in this paper is less simplified and correspondingly harder to solve, but note that it is still a simplification. If this paper’s claims are borne out, it is a methodological advance, not a foray into something cosmologists have been ignoring (let alone purposely ignoring).

This article’s failure to present what the actual paper says instead of a hobby horse narrative in no way absolves you from rudely accusing someone of incompetence. If you don’t like fibbing, I’d focus on backing your opinions more solidly (crazy idea: read the introduction of the paper) before you attack others.

My answer was to Dr."(Astrophysist [sic] here)" saying "This is complete BS."

If the previous relativistic models failed to produce results different from Newtonian gravity, it was, apparently, because they were wrong. Now, I don't claim to know anything about how to simplify GR solutions, but I know of people whose job it is to be able to simplify GR solutions correctly; and to be able to tell whether they have been simplified correctly. If they are getting that part of their job wrong, what reason do we have to believe they are doing the rest of their job any better?

Even if simplifying the maths is too hard for most of them, some one or other might have thought to run a direct numerical simulation, without any simplification. (Maybe have an undergrad do it? Or, every undergrad?)

> They "fitted" the rotation curves of three galaxies with their very obscure model with a bunch of parameters

I don’t quite follow this objection. Do you mean there are more free parameters in the model than data points so they could have fit anything?

Re: those dwarf galaxies. Their core (massive black hole?) still spins, right?

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