← all shorts

Person

Vesto Slipher

A man with gray hair and a mustache, dressed in a dark suit with a white shirt and black tie, stands against a brown background.

American astronomer (1875–1969) who spent decades at the Lowell Observatory in Flagstaff, Arizona, taking long-exposure spectra of faint spiral nebulae. By 1917 he had measured the radial velocities of 25 of them and found almost all receding at unprecedented speeds. His data, handed to Edwin Hubble a decade later, became half of the evidence for cosmic expansion. He never received comparable credit.

Mentioned in 2 articles