be proportional to the inverse square root of its distance from the center. A star one-half as far out from the core as Sol should speed through space at four times Sol’s speed. But measurements of many galaxies began to appear in the early 1980s showing that almost all of the stars in the spiral orbit at about the same speed, regardless of their distance from the core! Galactic “rotation curves” were flat. This is truly a huge anomaly. Something very basic about our worldview seems wrong.
