[graycat]

Something has orbits around galaxies failing to follow the law of gravity from ordinary matter. The orbits are as if there there is some more mass with gravity, mass that doesn't interact with light.

Something is in/near galaxies is bending light as if there were more mass there than there is from just ordinary matter.

So, for that extra mass, call it dark matter.

Seems simple enough.

"Flaw in the theory of gravity?" Maybe, but that seems to be the hard way to get an answer.

[dandelany]

Alternatively:

The orbits around galaxies fail to follow the law of gravity of ordinary matter. The orbits are as if our gravity calculations, which seem to work well otherwise, are flawed.

Something in/near galaxies causes them to bend light as if gravity were different.

So, for that region, call it a flaw in the theory of gravity. Seems simple enough.

"Unseen, never-before-detected form of matter which doesn't interact with any other matter except gravitationally?" Maybe, but that seems to be the hard way to get an answer.

This is tongue-in-cheek of course, but it's hard to trust intuition in these realms, especially when one person's intuition is another person's "hard way" :)

[rcxdude]

Yeah, but AFAIK all the explanations based around adjusting our theory of gravity have failed to match the results, and tend to be pretty complicated and thus prone to overfitting.

[AnimalMuppet]

Whereas, since you can adjust the hypothetical distribution of dark matter to be whatever you need it to be to fit the data, you cannot falsify dark matter this way, since proving that no possible distribution of dark matter could fit the evidence is pretty much impossible.

Still, to me there seems to be some level of equal implausibility in saying "our theory of gravity is wrong" and in saying "our theory of matter is wrong".

[bzbarsky]

From my limited understanding, what's interesting about the dark matter approach is that if you pick the distribution of dark matter to fit the rotational velocity profiles of galaxies that also just happens to be the distribution that has a good fit to various other unrelated data sets (cosmic microwave background fluctuations, say).

Now maybe there's a deep underlying reason we don't know about that makes those unrelated data sets in fact related to each other. Or maybe it just happens that the dark matter actually exists. But the point is that the dark matter theories we have were absolutely falsifiable, as the article points out. They made predictions that were then tested and so far the predictions have been correct.

[AnimalMuppet]

I stand corrected.

[Retra]

We have much more experience with matter, because we can interact with it on a variety of scales in a lab. Gravity is much harder to interact with, and thus much harder to explore. That's why it is quite a bit more likely that our understanding of gravity is incorrect.

[smil]

Exactly. Dark matter and dark energy is just a symptom of the standard model of physics being incorrect.

>Dark matter neither emits nor absorbs light or any other electromagnetic radiation at any significant level. According to the Planck mission team, and based on the standard model of cosmology, the total mass–energy of the known universe contains 4.9% ordinary matter, 26.8% dark matter and 68.3% dark energy.[2][3] Thus, dark matter is estimated to constitute 84.5% of the total matter in the universe, while dark energy plus dark matter constitute 95.1% of the total mass–energy content of the universe.[4][5][6]

Science is literally religious faith.

[apalmer]

Ummm... this is kind of thing is well in line with the history of science. Clearly dark matter is a fudge factor to make the current model of physics work. Obviously there is a flaw here somewhere, so there are multiple competing theories of which dark matter & dark energy are but one for explaining this. Some theories are more popular than others...

But pretty much within 5 years of a new falsifiable theory that can explain the situation which can be experimentally proven dark matter will go the way of the myriad of disproven theories... whereas religious faith would extend the belief in dark matter out for possibly thousands of years after it is shown to be experimentally incorrect.

So not 'literally' religious faith at all...

[dragonwriter]

> Dark matter and dark energy is just a symptom of the standard model of physics being incorrect.

Possibly, and if there was a better model -- one that was as good at predicting/explaining the observed effects for which the standard model works and did not require invoking dark matter and/or dark energy, the standard model would be dropped in a heartbeat. But right now the standard model + dark matter + dark energy is what works best, of the models that have been presented, at modeling what is actually observed in our universe. So it survives. For now.

Whether it will be resolved by an as-yet-unproposed tweak to the basic model or finding out that "dark matter" and "dark energy" are real things is yet to be seen.

[mpc755]

The notions of dark matter and the dark matter particle are incorrect. The mass which fills 'empty' space is beginning to be referred to as the 'dark mass' in order to distinguish it from the baggage associated with dark matter.

'Dark Energy/Dark Mass: The Slient Truth' https://tienzengong.wordpress.com/2015/04/22/dark-energydark...

"That is, all that we are certain about [is] the dark mass, not dark matter, let alone to say about the dark 'particle'."

Particles of matter move through and displace the dark mass, including 'particles' as large as galaxies and galaxy clusters.

The Milky Way moves through and displaces the dark mass.

The Milky Way's halo is the state of displacement of the dark mass.

The Milky Way moves through and curves spacetime.

The Milky Way's halo is curved spacetime.

The state of displacement of the dark mass is curved spacetime.

[kleer001]

> Science is literally religious faith.

No it isn't. Not by a long shot. Faith requires that you confabulate to a reach a certain cognitive destination. Science only allows models that conform to reality upon repeated testing.