[nynx]

Honestly, I'm a little tired of the whole dark matter thing. There's no evidence for it, and physicists keep coming up with more and more complex models to fit the data when they don't actually understand what's going on there.

Why haven't MOND or other theories become more popular?

Edit: MOND isn't great either - it just has a parameter that they tune until it matches the observation.

Edit 2: I am not a physicist, I am simply a concerned citizen.

[yongjik]

Honestly I'm not sure why some people oppose "dark matter" so much. We know there's something out of ordinary, it behaves like matter, and it doesn't interact with light (hence "dark"). Given that, "dark matter" is as inoffensive a name as possible. People are acting like we named it "quasiflavored eleven-dimensional supersymmetry carriers."

[daxfohl]

I think it's a natural reaction after Einstein. The whole physics world was certain about this Aether thing, and it turned out to be wrong and much more beautifully solved by plain geometry. "Dark matter", taken at surface level, sounds like going down the exact same rabbit hole.

There's a fundamental difference though. With dark matter, the evidence of the stuff is much more direct and precise. We can determine the shape and concentration of it. Aether on the other hand was a hand-wavy metaphysical concept from the beginning. There was never any experimental evidence that aether was a real thing; it was just a concept invented to patch up the inherent inconsistencies in electromagnetic theory near the speed of light.

[ifdefdebug]

> Honestly I'm not sure why some people oppose "dark matter" so much

But I think you might be after something:

> Given that, "dark matter" is as inoffensive a name as possible.

Precisely. Dark matter is boring. People want Klingons.

[StanislavPetrov]

Its not the name "dark matter" have an objection too, its misleading and/or confused attitudes like the one you yourself exhibit in your comment!

> We know there's something out of ordinary, it behaves like matter, and it doesn't interact with light

That's wrong, and presupposes the existence of dark matter, rather than treating it as a possibility. What we know is that our formulas don't match up with our observations. We don't know why that is. One suggestion is that there is some sort of invisible stuff out there that we cannot detect, but would make our formulas add up, so it could exist. Its perfectly legitimate to speculate about the existence of dark matter, and to set up different experiments to try to detect it, but its not fine to pretend that its "settled science" that dark matter is out there and its only a matter of finding it. Unless and until someone detects "dark matter" or figures out another reason why our calculations don't add up its existence will remain an open question.

[jjoonathan]

If MOND and Dark Matter both fit the data and MOND did it with few parameters while DM did it with a field of parameters, everyone would prefer MOND and it wouldn't be the slightest bit controversial. The problem is that MOND doesn't fit the data. Some galaxies behave one way, some behave the other way, and it isn't very inspiring when a MOND model fails to fit observations and its advocates try to hand-wave the problem away.

DM: we see complexity, let's treat it as fundamental.

MOND: we see complexity, let's ignore the inconvenient parts.

[dnautics]

Disclaimer, I'm not an astronomer.

I think that is a mischaracterization; IIRC, MOND fits the overwhelming balance of galaxies with a single parameter, and there are only a handful of exceptions (probably around in the hundreds or so?) out of all of the galaxies.

also: MOND doesn't explain intergalactic movement, or the clumpiness of the universe. But there's ALSO no good reason to believe that that "LCDM dark matter" does either, because by the "curve-fitting nature" of LCDM it could literally explain anything. If all of the oxygen in my room went to the northeast corner of my room and suffocated me, you could come up with a dark matter field that explained that phenomenon. As a scientist, that worries me. Also doesn't mean that LCDM is wrong.

[lisper]

"The most serious problem facing [MOND] is that it cannot completely eliminate the need for dark matter in all astrophysical systems: galaxy clusters show a residual mass discrepancy even when analysed using MOND. The fact that some form of unseen mass must exist in these systems detracts from the elegance of MOND as a solution to the missing mass problem..."

https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics

[dogma1138]

MOND brings it down to levels that could potentially be explained with missing baryonic matter and other Dark Matter candidates that fall within the standard model.

There are however other issues with MOND including that gravity is still instantaneous (in most variations) which we know with gravitational waves it isn't, as well as that most of them don't lend to the formation of stars and galaxies. If we take vanilla MOND then the universe as we know it shouldn't have been formed matter wouldn't clump up to form the formations we can see around us and the one we live on.

[DennisP]

I don't really have an opinion but in fairness, the article is about a discrepancy between the data and current dark matter models.

[ChrisClark]

> I am not a physicist, I am simply a concerned citizen.

I don't think you can even be a 'concerned citizen' on this topic without some introductory knowledge of dark matter.

[mehrdadn]

There's a lot of evidence for it, just not direct detection on it. It's like if you came into your room and saw writing on the wall, your carpets removed, your computer taken apart, etc. and then claimed there's no evidence anyone has been in your room just because you didn't physically find anyone in your room.

There are things to be frustrated about with the dark matter hypothesis (and I am too), but lack of evidence isn't one. Dark energy seems to be another beast though...

[joshocar]

There is a LOT of evidence for the existence of dark matter.

https://en.m.wikipedia.org/wiki/Dark_matter#Observational_ev...

[nynx]

What you've linked to is evidence that our understanding of gravity is wrong OR there is dark matter.

[dnautics]

MOND does not reject the observational evidence for Dark Matter theory, it just postulates that it primary cause is not a "non-baryonic particle that interacts only via the gravitational field".

[daxfohl]

It accumulates in blobs, around some galaxies, trailing others, and not in some galaxies at all. So the appearance and behavior of it matches the model that there's "stuff" there, not that there's some parameter missing from our gravitational model. With the latter you'd presumably get some less arbitrary accumulations of it.

[dnautics]

I think the point of MOND is that it explains a higher proportion of galaxies with a single parameter than something where you have to pick a parameter for each galaxy strictly from observation.

Key to note that this doesn't mean it's right. But one wonders why there isn't more skepticism about conventional dark matter theories.

Like what if I said "there isn't global warming, there's just a mysterious unobservable dark thermal input adjustment that we have to apply to every month's reading to make our models work out". You'd say that I was crazy.

[ajkjk]

Are you a physicist? What possibly makes you think you have enough background to disregard the (tremendous) evidence for it?

[dbsmith83]

I admit that I haven't been reading about dark matter lately. Last I checked, it had not been verified via experimental evidence. Is that still the case?

There is a difference between observations and _experimental_ evidence, which I think the GP was referring to.

[mellosouls]

To be fair, there is a lot of evidence for the phenomena described as "dark matter", but as yet zero detection of actual matter that fits it's properties.

Perhaps that is the complaint here - and asking for academic background is an argument from authority...

[tiborsaas]

If it's tireing for you imagine the scientists who dedicated significant amount of their lives to figure out what explains this baffling observation.

Another problem with MOND is that no matter how you tune it, it can't explain the Bullet cluster for example.

[dnautics]

Sure, but a counterexample of one or two could be literally anything. After all, conventional dark matter theories don't do a good job of explaining why there just so happens to be galaxies with highly-deviant clumps of dark matter.

If the bullet cluster is a great counter example for MOND, then conventional dark matter is highly opportunistic curve fitting (which doesn't mean it's not correct).

[T-A]

https://en.wikipedia.org/wiki/Dark_matter#Observational_evid...

[nynx]

Those are evidence for our physics not actually matching reality, not evidence for dark matter specifically.

[gbrown]

> There's no evidence for it

[citation needed]