All current 'hints' towards Dark matter not being "matter"

[AlenKovac]

I want to start by saying that I'm in no way trying to say that Dark Matter isn't a real pehonomenon in space. I also have no intention to sway one way or another. However, I feel like most scientiests are swaying towards the 'dark matter' is some kind of WIMP or such. It's much easier to read about 'proofs for' DM than 'proofs against' DM. This might be because there simply are more proofs for but it might also be that leading scientists are swayed towards one way because of fear of losing their jobs otherwise (since so much money is being spent on (and will be spent on) finding the particles).

I want to gather all half/minor hints towards DM not being what we believe it is (the hints towards it being matter is easy to find). All I can find is;

1. Abell 520

A cluster of galaxies colliding and the space is actually bent where the mass is (unlike bullet cluster - the smoking gun for DM). However, according to the wiki page it says the validity of this data is uncertain and that the scientists involved have starting doubting it. What's the current status on this find? Is it a 'hint' towards DM not being a real thing?
(I found this paper on Abell 520 from 2016, couldn't find any more recent work)

2. 21cm problem

This one is a bit more complicated to understand and fairly new so it's hard to say. I left the link in the header. But let's say this goes the way and the study gets proven to be right, what would it mean for DM as a theory?

3. Most galaxies have (roughly) the same amount of DM in them. It's would be more compelling theory-wise if some galaxies proved to have almost no DM. But none has been found as of yet. However there was a galaxy with 'no dm' floating around in forums a few months ago but that got rebutted a month after it came out.

Finally, what's your thought's on DM? Is it a 'solid' hypothesis given the current observations? How many more years will you give it before you start doubting DM being some sort of WIMP's?

 

[phinds]

This topic has been beated to death here on PF. I suggest a forum search.

That dark matter is SOMETHING is rock solid science. WHAT is is uncertain but MOND theories are not generally highly thought of these days so some kind of matter certainly seems the most likely

 

[AlenKovac]

This topic has been beated to death here on PF. I suggest a forum search.

That dark matter is SOMETHING is rock solid science. WHAT is is uncertain but MOND theories are not generally highly thought of these days so some kind of matter certainly seems the most likely

yeah I agree MOND theories aren't as good as explaining them. But what's the current status on A520?

 

[phinds]

yeah I agree MOND theories aren't as good as explaining them. But what's the current status on A520?

Never heard of it. I don't follow such things closely. Someone here likely knows though.

 

[Bandersnatch]

1. Abell 520

The opinions I've seen expressed on the forum were that it's an extremely messy system, and extracting anything clean out of it is always going to be a pain. The implication being, the data will be prone to misinterpretation one way or another.

2. 21cm problem

I'm not sure why you included this here. The issue is that there is some effect X. People ask: 'can we use DM to explain X'? The answer being: 'probably not'.
This is not an argument against DM in the same way as it isn't an argument against protons or hurricanes.

3. Most galaxies have (roughly) the same amount of DM in them.

Is this actually true? Are you looking at something else than Mass-to-Light ratios? (these can have something like two orders of magnitude spread, I think)