this post was submitted on 08 Jan 2025
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Science Memes

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vibes-based astrophysics (mander.xyz)
submitted 3 weeks ago* (last edited 3 weeks ago) by [email protected] to c/[email protected]
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Caption: an interview dialogue

  • Are dark matter models unsuited to explain observations? [the "dark matter models" and "to explain observations" parts are poorly edited onto the image, overlaying the original text]
  • In my view, they are unsuited.
  • Why?
  • That's my opinion, don't ask me why.

End of caption

Dark matter is the mainstream among physicists, but internet commentators keep saying it can't be right because it "feels off".

Of course, skepticism is good for science! You just need to justify it more than saying the mainstream "feels off".

For people who prefer alternative explanations over dark matter for non-vibe-based reasons, I would love to hear your thoughts! Leave a comment!

top 29 comments
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[–] [email protected] 31 points 3 weeks ago (2 children)

All models are wrong. Some are useful.

[–] [email protected] 10 points 3 weeks ago

This, a model is a human tool and it’s as useful as it is useful.

[–] [email protected] 10 points 3 weeks ago

Some are less wrong than others, depending on the application.

[–] [email protected] 14 points 3 weeks ago* (last edited 3 weeks ago) (3 children)

Didn't someone come up with an alternative model that said that, because galaxies vary in mass, time must also varies between galaxies; and said model was able to predict the effects of dark matter and dark energy?

Edit: it seems like a painfully obvious statement, which is why it confused me when I first read it. Like, no shit time is gonna vary between galaxies due to differences in mass.

[–] [email protected] 9 points 3 weeks ago

That disputes dark energy accelerating the expansion of the universe. But AFAIK it doesn't explain dark matter.

Still, I find it very compelling. And I hope it might also solve the crisis in cosmology. At the very least it should get rid of the lambda in lambda CDM.

[–] [email protected] 7 points 3 weeks ago

I've heard of something similar that is able to predict an effect of dark matter (the rotation curves), but AFAIK it couldn't match other observations (bullet clusters, etc.) correctly.

Do you have a link for the model you're talking about. I'm curious.

[–] [email protected] 4 points 3 weeks ago

You're (probably) thinking of timescape cosmology theory!

[–] [email protected] 13 points 3 weeks ago (1 children)

Isn't the question in itself wrong? "Are dark matter models unsuited to explain observations" suggests that dark matter is a model we invented to explain something else. But as I understand it, dark matter is the observation itself and we need to come up with an explanation for it. Cf. Angela Collier's video on exactly this.

[–] [email protected] 3 points 3 weeks ago (1 children)

But it is a model we invented no? To explain the astrophysical and cosmological observations.

Among all those observations, a commonality is that it looks like there is something that behaves like matter (as opposed to vacuum or radiation) and interact mostly via gravity (as opposed to electromagnetically, etc.). That's why we invented dark matter.

The "it is unsuited" opinion in this meme is to poke at internet commentators who say that there must be an alternate explanation that does not involve new matter, because according to them all things must reflect light otherwise it would feel off.

Once you believe dark matter exists, you still need to come up with an explanation of what that matter actually is. That's a separate question.

(I'm not trying to make fun of people who study MOND or the like of that. just the people who non-constructively deny dark matter based on vibes.)

[–] [email protected] 3 points 3 weeks ago (1 children)

No, as far as I understand it, it isn't something we invented. It is rather a placeholder for observations we made. In many different contexts we observe something that is matter but that doesn't seem to interact with anything else. We call this dark matter. And then there are theories of dark matter that try to explain the observations of dark matter. But dark matter is that what we observe, not a theory or invention.

[–] [email protected] 3 points 3 weeks ago (1 children)

I think we just differ on the terminology of invention versus observation. What draws the line between a well-supported theory and an observation in the end comes down to how tangible you think the data is.

[–] [email protected] 2 points 2 weeks ago

Yes, I see your point and agree :)

[–] [email protected] 8 points 3 weeks ago (1 children)

MOND is my personal favorite way to avoid dark matter.

[–] [email protected] 20 points 3 weeks ago (2 children)

MOND is a wonderful way to explain rotation curves but since then with new observations (bullet cluster, gravitational lensing, ...) MOND doesn't really hold up.

[–] [email protected] 6 points 3 weeks ago (1 children)

You might consider reading Accelerated Structure Formation: The Early Emergence of Massive Galaxies and Clusters of Galaxies. The paper is absolutely wonderful. The main thesis of the paper is, "Wow, the James Webb Telescope sure has been finding some remarkably mature galaxies for the early universe. Maybe we should consider the possibility that the models we use to predict galaxy formation, specifically lambda CDM, are incorrect and Non-Physical."

The author states the difficulty in the conclusion:

Despite the predictive successes of MOND, we do not yet know how to construct a cosmology based on it. In contrast, ΛCDM provides a good fit to a wide range of cosmological observables but does not provide a satisfactory explanation of the many phenomena that were predicted by MOND, nor is it clear that it can do so. We find ourselves caught between two very different theories that seem irreconcilable despite applying to closely related yet incommensurate lines of evidence.

The complaints about the early maturation of galaxies seen by the JWST was widely reported. My favorite line from that article:

“Maybe in the early universe, galaxies were better at turning gas into stars,” Chworowsky said.

Sure, it's not that our theories of cosmology are incorrect; things like star formation were just different back in the early universe. I guess you just had to be there.

[–] [email protected] 5 points 3 weeks ago (2 children)

I'm still far from convinced about MOND. But I guess now I'm less confident in lambda CDM too -_-

I'm inclined to believe it's one or many of the potential explanations in your second link. But even then, those explanations are mostly postdictions so they hold less weight.

[–] [email protected] 3 points 3 weeks ago (1 children)

I love the idea of MOND but it does seem like evidence is not in its favour overall. I remember getting an (I think) Scientific American magazine that featured it and I thought the idea sounded awesome. Unfortunately the universe doesn't care what we think haha

[–] [email protected] 1 points 2 weeks ago

Did the SA article come out before or after the article above? Because the JWST has been creating problems for lambda CDM. Take, for example, this Quanta Magazine article. The purport of the article is that, even though the data from the JWST seems to contradict ΛCDM, it really doesn't, if we just apply post-hoc modifications.

Why are the galaxies so bright at very high red shifts? Oh, the initial mass function was higher. Or it was super efficient star formation. Or the density of dark matter was higher in the early universe. Or the density of dark energy was higher, so the universe actually wasn't that young after all. Or a linear combination of these things, and maybe a few others, that we can fit to the data. You don't reconsider old theories in the light of new data, just apply more terms so that the old theory matches the new data.

For me, if the data starts to deviate from my model, it probably means that I need a different model

[–] [email protected] 2 points 3 weeks ago

To which McGaugh et al. had this delicious reply:

One does not simply turn all the available baryons into stars.

[–] [email protected] 3 points 3 weeks ago (1 children)

MOND isn't even a great way to explain rotation curves. It's pretty easy to make a pretty close model for the majority of galaxies, but there are a lot of weird outliers where it's pretty easy to say they just have more or less dark matter than usual, but MOND has a really hard time explaining them without making it so that physics works differently in different galaxies.

[–] [email protected] 2 points 3 weeks ago

I must admit I don't know that much about MOND being tested. But yeah, from a Lambda CDM point of view it is unsurprising that MOND would not work well for every galaxy.

[–] [email protected] 5 points 3 weeks ago (1 children)

What was it Anton on YT said once? Something about maybe Dark Matter turns out to be a boring "brute fact" that the only property it has is a weak interaction and nothing else.

[–] [email protected] 3 points 3 weeks ago

Particle physicists love the Weakly-Interacting Massive Particle dark matter model. But from a purely astrophysics point of view there is little reason to believe dark matter to have any interaction beyond gravity.

[–] [email protected] 3 points 3 weeks ago

More memri tv crossovers please

[–] [email protected] 3 points 3 weeks ago (1 children)

Anakin: In my view, it's the observations that are wrong!

Dark matter (WIMPs) has a lot of known issues, the largest one being that we should probably already have seen it (but not certainly, we just excluded almost all of it, not all). None of those is strong enough to really kill the theory, it is still the best one we have, but to firmly believe in it is something else.

But yeah, AFAIK the judge is still out on whether this is even a change from the previous model or we just calculated things wrong.

[–] [email protected] 3 points 3 weeks ago

WIMP is only one model of dark matter. A favorite of particle physicists. But from a purely astrophysics point of view there is little reason to believe dark matter to have any interaction beyond gravity.

[–] [email protected] 2 points 3 weeks ago (2 children)

Off topic, but what is the original source of the meme?

[–] [email protected] 1 points 3 weeks ago

What the other guy said, but also there’s a website for that and you don’t need to go digging on your own or posting again.

Weird advice.

https://knowyourmeme.com/memes/memri-tv

[–] [email protected] 0 points 3 weeks ago

It's a classic MEMRI TV meme. What MEMRI TV is would require a ..... "nuanced" explanation that I don't want to get into here. Look it up on Reddit or start a thread on [email protected]