The earliest evidence for dark matter (1930s) was galaxies moving in clusters were seen to have a higher average velocity than could be attributed to the total amount of visible matter. This was improved in the 1970s by observations of the velocities of stars within galaxies. They didn't fall off as a function of their distance from the central core, which suggested that most of the matter in galaxies actually lay in their periphery. More recently gravitational lensing has permitted astronomers to actually map where the dark matter must lie.
But the best evidence for dark matter comes from the first 370,000 years of time when large regions of space rung like a very large, very low frequency bell. Waves of normal matter were damped by photons carrying energy away, but the waves of dark matter were not damped, because they do not interact with photons. And these two kinds of waves interfered with each other gravitationally. This tale is told by the power spectrum of the Cosmic Microwave Background radiation.
So when you see an article claiming that dark matter does not exist, and the data can be explained by some alteration to the theory of gravitation (sometimes called MOND, Modified Newtonian Dynamics), and the article only talks about explaining the oldest data, not the best data, you can ignore it.
If their claim takes the metric tensor of General Relativity and adds additional structure in the form of vectors or scalars, that's just another field, which is to say more particles, and they're right back to dark matter again.
![[Image: 0060.jpg]](https://badinage1.files.wordpress.com/2023/08/0060.jpg)
But the best evidence for dark matter comes from the first 370,000 years of time when large regions of space rung like a very large, very low frequency bell. Waves of normal matter were damped by photons carrying energy away, but the waves of dark matter were not damped, because they do not interact with photons. And these two kinds of waves interfered with each other gravitationally. This tale is told by the power spectrum of the Cosmic Microwave Background radiation.
So when you see an article claiming that dark matter does not exist, and the data can be explained by some alteration to the theory of gravitation (sometimes called MOND, Modified Newtonian Dynamics), and the article only talks about explaining the oldest data, not the best data, you can ignore it.
If their claim takes the metric tensor of General Relativity and adds additional structure in the form of vectors or scalars, that's just another field, which is to say more particles, and they're right back to dark matter again.
