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!
Dark matter is a case of giving a phenomenon a name and then thinking that because it has a name you’ve explained it. Dark matter isn’t really an explanation, it’s essentially just a placeholder to say, “Our equations suggest there should be matter here but there isn’t, so maybe there’s some kind of matter we can’t observe? Or something?” It’s not an answer or an explanation, it’s just a term for an unexplained phenomenon that guesses vaguely about it what might be, and until we can verify the existence of dark matter through other means and explain why it defies other observations, it’s little more than a placeholder and cannot be treated as settled science. This isn’t really out of line with the mainstream view, the mainstream view is just that there aren’t any better explanations (yet) so that’s what we’re stuck with (for now).
Yeah it’s not settled by any means. Far from it.
But the hypothesis that it exists and is some kind of matter is pretty well supported through observing gravitational effects.
But isn’t that the whole reason that the concept was developed in the first place? It’s not very sound to come up with a hypothesis to explain an observation and then rely on that same observation to support the hypothesis. The concept needs to be able to predict and explain new observations, or else it has no utility and is still essentially just a placeholder.
You talked about, like, “vibes-based reasons,” but is there a reason to accept the explanation of dark matter aside from vibes? If it’s just about feeling satisfied that you have an explanation for the phenomenon, that’s vibes. Like, relativity, you have to accept and account for or GPS wouldn’t work nearly as accurately as they do. But everyone could reject the hypothesis of dark matter and it wouldn’t really change anything.
Explanations for things are a dime a dozen. There’s no real value in having an explanation (other than personal satisfaction, i.e. vibes) for something unless that explanation helps you to make predictions or manipulate objective reality in some way. That’s not to say that it couldn’t, at some later date, meet those requirements, but at this point dark matter is barely anymore useful than saying a wizard did it - a hypothesis that also explains the observations perfectly well while being only slightly less congruous with the rest of our understanding of physics.
The concept needs to be able to predict and explain new observations, or else it has no utility and is still essentially just a placeholder.
They first came up with it to explain galactic rotation curves. After that, many new observations came in and the model successfully explained them. To name a few: bullet cluster dynamics, gravitational lensing around galaxies, baryon acoustic oscillation.
Like, relativity, you have to accept and account for or GPS wouldn’t work nearly as accurately as they do.
It is neat that general relativity is used in GNSS, but I’d bet that GNSS could still be invented even if we don’t know general relativity. Engineers would probably have came up with a scheme to empirically calibrate the time dilation effect. It would be harder, but compared to the complexity of GNSS as a whole not that much harder.
There’s no real value in having an explanation (other than personal satisfaction, i.e. vibes) for something unless that explanation helps you to make predictions or manipulate objective reality in some way.
You can make a lot of predictions with Lambda CDM. But yeah they’re not going to help anyone manipulate objective reality. Even so, >95% of math, astronomy, and probably many other fields of research don’t help anyone manipulate reality either. It’s harsh to say they have no value, but perhaps you’re right.
At least let me say this: finding explanations to satisfy personal curiosity (doing it for vibes, as you put it) is different from projecting personal feelings onto objective understanding of reality (the vibes-based astrophysics I was referring to in the meme).
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.
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.
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.
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.)
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.
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.
Off topic, but what is the original source of the meme?
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 !nostupidquestions@lemmy.ml
All models are wrong. Some are useful.
Some are less wrong than others, depending on the application.
This, a model is a human tool and it’s as useful as it is useful.
Im not reading on that specifically right now, but I think one problem with dark matter is that it’s not a falsifyable hypothesis and likely never will be. I can make up an explanation over any body of proof of a phenomena and just say that my explanation is due to undetectable things. An alternative theory would be something like stars spinning produce electromagnetic fields which account for the apparent acceleration that’s attributed to gravity caused by an invisible mass. You can measure electromagnetic fields and you can refine models of our sun to try and prove it, and then reach for further discovery. Dark matter feels like a well that’s that. Can’t see it, can’t touch it, can’t prove it doesn’t exist. It should be what remains after we’ve actually tried explanations based on observed phenomenas. That’s just my barely informed take on it.
It’s an observation with several theories to explain the observation. So far no theory seemed to be conclusive.
This is a very fair take, but I’d say dark matter is harder to falsify, but not totally unfalsifiable.
You can’t see it, true. But what makes sight so special? We can’t smell stars either. You just need to sense dark matter in some other way. Namely gravity! We have seen the way visible matter orbit, and that points to dark matter. We have seen gravitational lensing due to dark matter. Hopefully soon we’ll observe gravitational waves well enough to sense dark matter around the regions the waves are being emitted from.
Most individual dark matter models are falsifiable (and many have already been falsified) through non-gravitational means too. People have been building all sorts of detectors. The problem with this is that detectors are expensive and there are always more models beyond any detector’s reaches.
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.
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.
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.
You’re (probably) thinking of timescape cosmology theory!
MOND is my personal favorite way to avoid dark matter.
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.
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.
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.
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.
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.
More memri tv crossovers please
