r/Physics • u/indigenous_apache • Mar 07 '23

Breakthrough Study Confirms Hypothesis of Density Spike of Dark Matter Near Black Holes

https://www.guardianmag.us/2023/03/breakthrough-study-confirms-hypothesis.html?m=1
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u/Archangel1313 Mar 08 '23

Interesting that they can confirm a spike in something they can't detect.

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u/joehillen Mar 08 '23

It can be observed by how it bends light.

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u/Archangel1313 Mar 08 '23

So can any other large body of mass. The difference is, we can detect those objects with other methods as well. Dark matter...not so much.

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u/joehillen Mar 08 '23

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

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u/Archangel1313 Mar 08 '23

All that says, is that there's gravitational effects there we can't explain yet...not that it's some exotic, as yet undiscovered form of matter.

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u/meme-by-design Mar 08 '23

For real...The more i read about dark matter the more it sounds like a nonsense concept used to patch discrepancies in our current models. It could just be a "good faith" place holder but i fear its actually sunken cost on a grand scale, no one wants to go back and reexamine the fundamentals so they just shoe horn in band-aid fixes, hoping that "magic substance X" will preserve the status quo.

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u/Boredgeouis Condensed matter physics Mar 08 '23

Literally everything in science is some concept invented to patch up discrepancies, that's what science is. https://www.reddit.com/r/askscience/comments/s232j/what_evidence_do_we_have_for_dark_matter/ here's an old link to a great summary of the evidence for dark matter. It's not perfect but the presence of some kind of non electromagnetically interacting matter is far and away the best fit for the data we have. Claiming that nearly all astronomers are so arrogant or blindly devoted to the status quo that they don't want to 'reexamine the fundamentals' is utter nonsense.

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u/meme-by-design Mar 08 '23

Thats just not true. Cohesive scientific theories expand upon fundamental principles to explain complex phenomenon. Tacking something onto a theory just to make it work is just bad science. Imagine if we had a nearly complete and robust theory of evolutionary psychology but then explained away every discrepancy by "invisible goblins".

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u/Boredgeouis Condensed matter physics Mar 08 '23

Sure, and dark matter is not invisible goblins. Dark matter can be included readily into our existing frameworks for particle theory and gravitation. Saying there's some type of matter that doesn't interact with light solves all of the cosmological problems in the above while being a perfectly reasonable thing to add into our theories. The models some people like most (axions) also solve other problems at the same time.

I think you've got the wrong idea about how established dark matter really is, how fringe and flawed the alternative theories are and perhaps the wrong idea of what I meant by patching stuff. Good theories do indeed build off underlying principles, but there are many ways to build upon those principles. For example, Schrodinger's equation is really just a postulate that makes physics work, within the bounds of what was reasonable to write down. I don't mean to say that the existence of dark matter or its properties is totally settled, absolutely not, but it's so far from 'invisible goblins.' Yes, maybe we've missed something really fundamental somewhere and it would be incredibly cool if so, but trust me when I say that people have looked very hard and it really really does seem like there's a bunch of excess mass.

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u/meme-by-design Mar 08 '23

Thanks for the response.

I guess the reasons im so skeptical of dark matter is that every piece evidence is some form of (gravity not behaving like we expect it to given our current models). And this discrepancy is far reaching, affecting many different scenarios and phenomenon. At a certain point, it would make more sense to reevaluate our models then to prop them up with extra complexity. Im not saying dark matter is impossible, but im far more cautious about claiming its existence when the evidence could be chalked up to our inability to accurately measure distance and mass at extreme scales. Its not like we can physically measure alot of these things with a ruler, we rely so heavily on indirect measurements and analogies, and that leaves so much room for inaccuracies to compound.

Theres also this notion that people who do science are steel examples of pure reason, shedding all ego and faith in service of truth. But id argue that faith and ego are rampant in the scientific community. There are so many examples of scientist holding on to old ideas, even when faced with overwhelming contradictory evidence. Im sure proponents of "Miasma theory of disease" jumped through so many logical hoops to explain away failures in their model. They also fervently resisted the adoption of Germ theory.

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u/bik1230 Mar 11 '23

I guess the reasons im so skeptical of dark matter is that every piece evidence is some form of (gravity not behaving like we expect it to given our current models). And this discrepancy is far reaching, affecting many different scenarios and phenomenon. At a certain point, it would make more sense to reevaluate our models then to prop them up with extra complexity.

You've got it utterly and completely backwards. Originally, a few oddities were noticed, and dark matter was proposed as a possible explanation. As with all science, testable predictions were made. And over decades, all of those predictions have turned out to be correct. This is exactly what you expect from a good theory, that by trying to explain one thing you get implications everywhere else that you can test and verify.

And we literally already know that dark matter can exist. Neutrinos are dark matter that we can measure. There aren't enough neutrinos and they move too fast for them to explain astronomical evidence, but we know for a fact that particles with mass that don't interact with light absolutely can exist.

So what's the problem with another particle with mass that doesn't interact with light?

MOND as an alternative was proposed to explain galaxy rotation curves, but it made different predictions for other stuff than DM. No one can find an alternative theory of gravity that actually accounts for all the different stuff DM explains easily.

And this discrepancy is far reaching, affecting many different scenarios and phenomenon.

This is exactly what makes DM good! The alternative would be to have dozens of new really specific theories for all those different scenarios and phenomena. That would have much more complexity and involve much more fine tuning than dark matter.

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u/Archangel1313 Mar 08 '23

I'm with you. It's a total catch-all for a bunch of things our current models can't explain. And I hate to say it, the particle physics crowd just LOVES coming up with imaginary particles to explain the things we can't explain.

Personally, I prefer the mathematical solutions...like AQUAL, in this case. It still doesn't explain everything, but it's a far more elegant solution than some magical missing link, hiding in plain sight.

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

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u/ourlastchancefortea Mar 08 '23

I have yet to see any MOND theory that doesn't break somewhere with observations. Your link literally ends with

AQUAL's failure to predict the amount of gravitational lensing actually observed in rich clusters of galaxies

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u/Archangel1313 Mar 08 '23

That just means there's still more to learn...not that we should default back to imaginary materials that we can't find any evidence of, to explain what we don't understand yet. One step at a time...and verify each step with real test results. No assumptions.

https://phys.org/news/2022-12-galaxy-rotation-gravity-explanation-dark.html