> when I hear someone suggest an alternative theory I don't immediately feel the need to group them with everything I think is wrong with the world Modified th

> when I hear someone suggest an alternative theory I don't immediately feel the need to group them with everything I think is wrong with the world Modified theories of gravity are not new and there is nothing immediate about my feelings on them. I understand homeopathy, and I am very confident that the idea that water has a special memory for particular chemicals is very silly. In the same way I understand MOND theories, and they are mostly silly. > That's how science works. Scientists are not prophets, they do not have the luxury of starting with all the answers. You are unfamiliar with the history of these theories if you think that their changes have been in any way scientific. MOND originates when the first observations of dark matter were very simple: galactic rotation curves. It was a reasonable attempt to explain why stars at galactic edges rotate faster than you would expect. Later, we got much more detailed observations which revealed that there was actual, complex structure to those orbital perturbations. Structure that is totally independent of the visible matter. We found the Bullet cluster, where 2 galaxy clusters are orbiting a third invisible cluster. Rather than admit some of this structure could not be explained, MOND theories grew wildly more complicated, and starting adding in more and more terms with arbitrary constants attempting to fit each new piece of data. That is not scientific. It's not how we got from Newton to Einstein. It's Aether theory. There are certainly physicists who do respectable work on MOND. They put that work out as a proposal, and recognize how good the evidence for dark matter is. They are a minority of the proponents, and I really mean that. There are a huge number of people publishing fringe time-cube types of theories about it. I am not lightly comparing it to homeopathy. https://en.wikipedia.org/wiki/Time_Cube https://en.wikipedia.org/wiki/Time_Cube