The center of the Milky Way might not be a black hole after all | Hacker News Reader

The center of the Milky Way might not be a black hole after all

popularmechanics.com

6 pointsStevvo5 comments

I've always found the idea of dark matter difficult; without direct observation it's asking for a leap of faith as much a theology does.

That's not particularly accurate. Dark matter isn't just a thing people thought would be cool if it existed.

We've got a bunch of observations that, combined with our knowledge of physics, indicate there is more mass out there than we can see. But we haven't been able to figure out what it is. Hence, dark matter.

Could dark matter not exist? Sure, but it would require some pretty big changes in our understanding of how things work. There are also multiple efforts out there trying to find the stuff.

At any rate, multiple aspects of dark matter are a very far cry from being remotely comparable to theology.

Dark Matter was first postulated because galaxy rotation curves strongly suggested if there was not unseen matter, galaxies would fly apart. But these observations of galaxies were each of a galaxy in isolation, not taking into account the gravitational effects of other "nearby" galaxies. In essence, Dark Matter is a fudge to explain the observation that galaxies are not flying apart. Since, other observations that can't be explained have been lumped into Dark Matter. But it turns out, Dark Matter is unnecessary to explain galaxy rotation curves.[0] Galaxies are never gravitationally isolated. They always come in clusters and superclusters.

[0] https://www.youtube.com/watch?v=PL0ewiwqoTw

The question is, without the need for Dark Matter to explain galaxy rotation curves, what are the remaining reasons for the need for Dark Matter?

You yourself mentioned there were additional reasons 'lumped in' that I imagine answers your own question.

I have to say I'm a little baffled by the tone of this response. It feels to me like you're implying physicists, in the general sense, came up with a hypothesis of dark matter to explain an observation, and then for no particular reason kept the idea of dark matter even after getting rid of any reason to continue to need dark matter to explain anything. As if the entire scientific community simply forgot to get rid of a particularly intuitive hypothesis after it was no longer useful, and the only people to recognize this are random folks on the internet.

I'm no stranger to being suspicious or doubtful about authorities in general, and academia in particular, but I can't imagine putting forth the idea that nobody in the scientific community has never simply considered dark matter might not exist. It's just not a plausible situation, particularly considering how many lay folk have trouble with the idea. I'm sure every single astrophysicist has been confronted with this kind of question multiple times.

And yet dark matter remains. That should say something about the current state of our observations, and how much dark matter is needed to explain them.

Completely agree. I think it's the aether of modern science. And I believe that one day all the discrepancy between measurements that lead to the idea of dark matter will be explained by a new (and by that time seemingly obvious) approach to how weak forces interact with mass.

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