According to models and simulations, all galaxies should be embedded in dark matter haloes, whose densities peak at the galactic centers. On long enough timescales, of perhaps a billion years, a single dark matter particle from the outskirts of the halo will complete one orbit. The idea of dark matter has been with us for nearly a century, although not everyone remembers that fact. (Credit: NASA, ESA, and T. Brown and J. Tumlinson (STScI))

Who discovered dark matter: Fritz Zwicky or Vera Rubin?

Back in the 1930s, Fritz Zwicky postulated the existence of dark matter. No one took it seriously until Vera Rubin’s work: 40 years later.

It’s hard to believe, but the idea that the Universe was dominated not by normal matter but rather by dark matter — a novel form of non-interacting matter that’s completely distinct from protons, neutrons, and electrons — goes all the way back to 1933. For decades, the overwhelming majority of the leading astronomers and physicists dismissed the idea as being ill-motivated, and it gained very little traction on both the theoretical and observational fronts throughout the ’30s, ’40s, ’50s and ’60s. It was only with the novel results and improved instrumentation initially leveraged by Vera Rubin and Kent Ford, and then further developed by Rubin on her own, that dark matter was brought into the cosmological mainstream in the 1970s.

But did either Fritz Zwicky, who first presented that 1933 evidence and even coined the term dunkle materie, which directly translates to dark matter, or Vera Rubin actually discover dark matter, or the overwhelming evidence in favor of it? Or is it unfair to say that dark matter was actually discovered by either of them, including up through and including the present day?