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dern_the_hermit t1_jc8fda9 wrote

Reply to comment by the_JerrBear in In defence of dark energy | Nobel Laureate and dark matter pioneer James Peebles answers critics of dark energy. by IAI_Admin

"apart from its gravitational effects" is a pretty huge thing to just ignore like that, bud.

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the_JerrBear t1_jc8h0zt wrote

sir bud dude, dark matter is a numerical correction to GR to match observed gravitation in galaxies, so he says "apart from" because it would be absurd to suggest that gravitational observations are direct evidence of dark matter

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sight19 t1_jc9u6zv wrote

And BAO. And CMB anisotropy. And the Bullet Cluster. And DM free galaxies. And early -universe structure formation. DM works on a huge range of scenarios. Even MOND requires DM to function properly...

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dern_the_hermit t1_jc8ho05 wrote

Literally all scientific models are made up to match observations. That's how the scientific method works.

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the_JerrBear t1_jc8jd8d wrote

yes, and so far no explanatory models for dark matter have been successful. Including dark matter as a parameter to match observed data is not the same thing.

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dern_the_hermit t1_jc8lsj0 wrote

We don't have a model for dark matter. It is called "dark" because it is unknown. We are currently in the early stages of creating a model to explain observations, one good enough to make predictions. Several models, actually, of which dark matter - that is, "matter that only interacts gravitationally" - is the only candidate that can explain the widest range of observations.

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the_JerrBear t1_jc8wdpc wrote

it's called dark matter because it only interacts gravitationally, not because we can't explain why it should be there. dark matter is not a bad model, it does explain observations well. we are not exactly in the early stages as far as that is concerned. nor are we in the early stages of attempting to explain what exactly that matter is, a lot of things have been ruled out that seemed promising at first. i would agree that the dark matter hypothesis is the most attractive solution available to us now, but the continuous failure of dark matter particle experiments, along with no unified theory to work from, makes it difficult to say that it is probably the right one. General relativity does not predict dark matter - we infer it from our observations. No experiment has been able to confirm hypotheses about the origins of dark matter, and there have been quite a few of them so far. It's good that we've come up with lots of ideas, and it can't hurt to keep trying, but we also know that general relativity and the standard model are not complete theories, so it seems unreasonable to me to argue that, because general relativity is nearly perfect, we shouldn't doubt dark matter.

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dern_the_hermit t1_jc8xhkb wrote

> it's called dark matter because it only interacts gravitationally, not because we can't explain why it should be there.

No, the notion that it only interacts gravitationally came much later. Previously it was assumed that it might simply be... dark matter, regular old gas, dust, rocks, stellar remnants, black holes, etc. that were not luminous. Take a look at MACHOs and WIMPs for theories about "dark matter" being regular standard model stuff that simply wasn't glowing.

It wasn't until decades later that "it only interacts gravitationally" became the dominating notion, entirely based on the preponderance of observations indicating something like that.

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the_JerrBear t1_jc8ysof wrote

Okay, I concede you that. It started out as "matter we can't see," and today a popular interpretation of that is that it doesn't interact with light at all. My mistake.

But, that also wasn't really my point.

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dern_the_hermit t1_jc8zs1t wrote

Your point was some crude dismissal of dark matter based on what seems to be a gross misunderstanding you have. Sorry for correcting your misunderstanding. It must hurt your feelings, being corrected.

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the_JerrBear t1_jc90lsw wrote

at no point have i dismissed dark matter, i have only presented arguments against the evangelization of dark matter, which this article supports. you argued beside the point, and have now volunteered yourself to exit the conversation.

rest easy, your words are as sharp as you are

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dern_the_hermit t1_jc91i3y wrote

"the bit where he says that no evidence doesn't mean it doesn't exist is frankly embarrassing" was pretty damn dismissive dude, GTFO with that dishonest-ass nonsense lol :D

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the_JerrBear t1_jcfency wrote

if you interpreted that as an outright dismissal that dark matter is correct, then again, you have entirely missed the point... Saying that "not having evidence doesn't mean it doesn't exist" is not a strong argument for dark matter, or a strong argument against alternatives. It's pleading, and doesn't really imply anything meaningful. I hear it when people ask for proof that god exists.

I don't understand why you insist that I have claimed dark matter is incorrect, maybe I am failing to communicate my point properly, but that definitely is not it at all. I would appreciate it if you took some of your valuable time to respond to literally anything else that I have actually said, thanks

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YawnTractor_1756 t1_jc8jx9e wrote

That doesn't mean any scientific model is correct. I can make a model with gravitons to explain gravity, it doesn't mean they exist. Same with dark matter.

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dern_the_hermit t1_jc8l4mp wrote

All models are only as good as their ability to explain observations and make predictions.

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YawnTractor_1756 t1_jc8lcof wrote

That's false. I can imagine that electrons are little conscious demons with mass of electron and charge of electron. It will explain things right, but it will contain unnecessary and unproven assumptions.

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