Vera Rubin Publishes Galaxy Rotation Evidence for Dark Matter

Astronomer Vera Rubin and instrument-maker Kent Ford published rotation curves for 21 spiral galaxies in the Astrophysical Journal, demonstrating that stars at the outer edges of galaxies orbit at the same speed as those near the center. This flat rotation pattern contradicted predictions based on visible mass and implied that galaxies contain five to ten times more unseen matter than observable stars and gas. Their systematic survey, conducted at the Carnegie Institution using Ford's image-tube spectrograph, provided the most persuasive observational evidence supporting the dark matter hypothesis.