Dark Matter's observational evidence is widely attributed to Vera Rubin based on her observation of galaxy rotation curves with Kent Ford in 1970s, which was later confirmed by Albert Bosma in 1978.

However, it was in the late 1930s that Fritz Zwicky inferred the presence of dark matter based on his observations of Coma galaxy cluster using the virial theorem. Herein lies my confusion. Why does the scientific community and people, in general, give credits to Vera Rubin instead of Zwicky for inferring/observing the evidence for dark matter? Or, is the recognition given because she independently strengthened Zwicky's observation thereby confirming the existence of dark matter?


You have a clear view of the history, and it wasn't an independent confirmation, it was simply the best evidence. Whenever one talks about the discovery of dark matter, one should start with Zwicky, and move to Rubin. One might do something similar with the Big Bang, starting with Hubble, and moving to Penzias and Wilson. Normally we give credit both to the initial discovery, and to the confirmation, but it is the most conclusive evidence that generally gets associated the largest credit. After all, it was Edgar Allan Poe who first described the Big Bang model, but he gets no astronomical credit because he provided no evidence. Zwicky certainly did better than that, so does deserve (and should receive) much credit, but there were still many doubters in his day, much as with Hubble and the Big Bang. Perhaps Zwicky's role contributed to the reason that Rubin never received the Nobel prize, I hope it wasn't simply the unspeakable reason, but of course it's too late now for both of them.

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  • $\begingroup$ Actually, it seems that both Jacobus Kapteyn and Jan Oort were a few years earlier than Zwicky postulating Dark Matter based on observations and calculations. $\endgroup$ – Thriveth Dec 30 '16 at 21:39
  • $\begingroup$ Oort did make similar observations a year earlier, and certainly deserves mention in the historical story, but it was Zwicky's genius to speculate that what was responsible was a new type of matter, something invisible, not just stars with a higher mass-to-light ratio than we thought. Zwicky had a long history of thinking outside the box, and coming up with crazy ideas (like gravitational lensing and neutron stars) that ended up becoming mainstream astronomy much later. $\endgroup$ – Ken G Dec 30 '16 at 21:58
  • $\begingroup$ According to the Wikipedia entry on DM, Jacobus Kapteyn speculated that there was Dark Matter in 1922 based on stellar velocities. And sure, Zwixcky was bolder, but that was his style and the flipside of this gemius was all the very wrong predictions and postulates he also made, weeded out of our collective memory by survivor bias. Btw. Big Bang was Lemaitres idea, not Hubbles... ;-) $\endgroup$ – Thriveth Jan 1 '17 at 21:45

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