> Then some more experimental evidence comes in (galactic radial velocity), and we are thinking about modifying the theory a bit more (MOND). This is good for the radial velocity explanation, but not certain other things. We suppose there's some dark matter, and think about the consequences that would have. Then we see evidence consistent with that.
Just to be clear, in case someone interprets that as being a time-ordered list, the existence of some "dark" matter was the proposed explanation prior to the development of MOND (though MOND followed very quickly).
Robust evidence for dark matter is generally (rightfully) attributed to the work of Vera Rubin (as in the parent article), but it is worth noting that Friz Zwicky also proposed dark matter in the 1930s to explain the velocities of galaxies in clusters.
Just to be clear, in case someone interprets that as being a time-ordered list, the existence of some "dark" matter was the proposed explanation prior to the development of MOND (though MOND followed very quickly).
Robust evidence for dark matter is generally (rightfully) attributed to the work of Vera Rubin (as in the parent article), but it is worth noting that Friz Zwicky also proposed dark matter in the 1930s to explain the velocities of galaxies in clusters.