oh my god it would not surprise me hahaha I hate how that suddenly makes it make more sense

Comments here are weird. Dark matter is just as accepted by the scientific community as anything else. There's a ton of evidence for it and yet redditors know better than all the world's best astronomers? Weird lol

>A type I Kardashev civilization is able to harness and consume all the energy available to it on a single planet, approximately 1016 watts

Is this supposed to be 10^16? 1kw seems laughable in this context

This video is really good rundown of why astronomers are confident that dark matter exists even though they haven't directly detected it yet. The indirect evidence is overwhelming and can't be explained by any kind of ordinary matter or modifications to gravity. You're right that there are a lot of unanswered questions about dark matter - it's one of the biggest unsolved problems in science.

https://youtu.be/nbE8B7zggUg

I recommend Dr Becky's channel in general for astronomy content. She's a PhD astrophysicist and great at explaining deep concepts in astronomy and cosmology

From the same wikipedia article:

> The most serious problem facing Milgrom's law is that it cannot eliminate the need for dark matter in all astrophysical systems: galaxy clusters show a residual mass discrepancy even when analyzed using MOND.[2] The fact that some form of unseen mass must exist in these systems detracts from the adequacy of MOND as a solution to the missing mass problem

MOND still requires dark matter to exist.

> Except they can't see it, nor can they prove it yet.

What I mean to say is that everywhere astronomers look, there isn't nearly enough mass to account for the gravitational effects they see. (It's like how astronomers observed black holes indirectly, by seeing their gravity affect nearby stars before the EHT got a direct photo) This is called the "missing matter problem" and dark matter is the best explanation they have.

> we don't understand enough about gravity

If a modified theory of gravity was proposed that offered a better and more consistent explanation than dark matter, then it would be the dominant theory. The best attempt at this is called MOND, and it can explain fast galaxy rotation but none of the other observed phenomena that point towards dark matter, so it's not considered a better explanation than dark matter

Dark Matter is every single place that astronomers look. Everywhere. Every galaxy rotates faster than it should, gravitational lensing from huge galaxies always shows a big excess in mass from what's visible, large galaxy clusters don't have enough visible mass to stay held together, and the CMB should be more uniform unless there's way more hidden mass in the universe.

All of these discrepancies are explained by there being some kind of matter that interacts with gravity and not light. Astronomers aren't saying "this is exactly what dark matter is", they're saying "the most reasonable explanation is that there is some kind of matter we can't directly see that is exerting all this gravitational force"

What part of dark matter are you "not convinced" on? The data is there. Astronomers have simply observed these gravitational anomalies and there has to be *something* causing it

something is exerting a crazy amount of gravitational force on all the matter that we can see, and there's no explanation for ordinary matter on the periodic table accounting for the massive difference in the amount of visible matter vs. the amount of mass required to explain those observations. And no one has come up with a modified theory of gravity that explains those discrepancies nearly as well as dark matter.

So until we have a better theory, the Lambda Cold Dark Matter model of cosmology will continue to be the best model.

It's frustrating that it hinges on these particles barely, if at all, interacting with anything else, other than gravitationally. But the universe is indifferent towards whether we can directly observe it or not. The idea that some particles have extremely weak interaction is not far fetched. Trillions of neutrinos are passing through you right now without interacting

Not an astronomer, but I would guess probably not, since we need several times as much dark matter as ordinary matter. Also, judging from the picture, it looks like the graveyard mass is still concentrated in the center, not in a ring surrounding the galaxy.

It's also important to remember that galaxy rotation is just one of several phenomenon that dark matter explains. These stellar graveyards inside galaxies wouldn't explain the dynamics of galaxy clusters or the CMB