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praetorion999 t1_ja859zd wrote

Reply to comment by OddClass134 in How to make a model of dark matter and energy? by Poise-on

Haven't the effects of it been observed like through gravitational lensing or is it still possible that a different theory of gravity is correct and explains it without dark matter?

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mkorman11 t1_ja8x7iv wrote

The effects of dark matter have been observed through a variety of effects across a vast array of scales, from galaxies, to galaxy clusters, to the cosmic microwave background.

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OddClass134 t1_ja8hbtw wrote

I'm not an expert, but I did attend a talk with an expert last week. It seemed his* theory is sort of neither, but rather that general relativity models just aren't being applied correctly. So underlying theory is the same, dark matter doesn't exist, but the math isn't mathing.

Edit for clarity

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praetorion999 t1_ja8kv0d wrote

Wait they actually said dark matter doesn't exist? We already know general relativity is wrong/incomplete because it isn't quantum compatible

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OddClass134 t1_ja8lq8e wrote

I mean doesn't exist in the sense of it not being-- as is commonly implied-- a "thing" that is invisible to us. It does exist in the sense of being the name of an observed inconsistency with our models, but the theory he presented was that it is a failure of the models to accurately model what we already know about, rather than it being that there is something out there (invisible mass, undiscovered particles etc) we don't know what it is.

Just one guy though. I'm sure opinions differ.

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ForTech45 t1_ja8tj6a wrote

I think you misheard what that guy said, because the leading theory is still 100% an unknown subatomic particle, and I would hazard to guess that 90-95% of physicists in a field involving dark matter believe that it is just that— matter that only interacts with gravity, or interacts extremely weakly with the other known interactions.

Most of the debates around dark matter are around the question of “what TYPE” of matter is it and there is really only one fleshed out alternative theory— MOND and it’s various offshoots— and it’s clunky and overly complex due to initial failures, and it still fails fully resolve the initial issues that led to the need for dark matter.

A universe filled with a cold subatomic particles that ONLY interact with gravity (not even itself) not only fixes most of the problems that required dark matter in the first place, but people are using it in other areas (universal structural evolution and such) and it works there, too.

Until dark matter is experimentally observed, it is still an open area of research…. But given decades of failures of alternative theories and cutting edge research discounting other theories, it’s getting harder to treat the cold WIMP theory as anything but accepted.

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OddClass134 t1_ja9iixt wrote

>I think you misheard what that guy said, because the leading theory is still 100% an unknown subatomic particle, and I would hazard to guess that 90-95% of physicists in a field involving dark matter believe that it is just that— matter that only interacts with gravity, or interacts extremely weakly with the other known interactions.

Ah, well yes then, I suppose that is the leading theory. That was not however the theory he presented.

He did not speak directly to or for its existence, but he did speak about how many of the effects attributed to dark matter may well be explained through re-examination of the theory of general relativity itself.

He began the talk with a criticism of a lot of high energy physics and particle physics. The association may have been one I made on my own, but the implication seemed to be that this theory was an alternative to the subatomic particle theory.

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ForTech45 t1_jaa67si wrote

What did he call the theory? What was the speakers name?

There are many alternatives, but very few are fleshed out and most are just frameworks

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OddClass134 t1_jaabdhx wrote

I dont hope to put anyone on blast, as it wasnt my presentation or my paper and I may be wrong.

I also think Im not being clear here when I say "theory" and considering the topic, I probably shouldnt throw that term around. I meant more the argument of looking at modifications of GR rather than for undiscovered particles. Which modification one supports is a different discussion.

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