S8 Ep855: The 100-year search for dark matter began in 1922 with Dutch astronomer Jacobus Kapteyn, who was the first to use the term "dark matter" in a scientific paper. Kapteyn realized that the gravity of unseen matter must govern the motions of stars. His studen
S8 Ep855: The 100-year search for dark matter began in 1922 with Dutch astronomer Jacobus Kapteyn, who was the first to use the term "dark matter" in a scientific paper. Kapteyn realized that the gravity of unseen matter must govern the motions of stars. His studen  
Podcast: The John Batchelor Show
Published On: Mon May 11 2026
Description: The 100-year search for dark matter began in 1922 with Dutch astronomer Jacobus Kapteyn, who was the first to use the term "dark matter" in a scientific paper. Kapteyn realized that the gravity of unseen matter must govern the motions of stars. His student, Jan Oort, later expanded on this by studying the vertical "up and down" motions of stars in the Milky Way to estimate the mass in the galactic plane. Fritz Zwicky provided a major breakthrough by observing the redshift of galaxies in the Coma cluster, concluding they moved too fast for visible mass to hold them together. Zwicky termed this missing mass "Dunkle Materie." These early pioneers identified a gravitational discrepancy—the "elephant in the universe"—that would define modern cosmology as scientists began hunting for what they could not see. (1/8)LAUNCHING 2026 RST