Bertil Lindblad

In the 1920s, Lindblad proposed that the Milky Way rotates differentially, meaning that stars at different distances from the galactic center orbit at different speeds. This theory explained the apparent stellar velocities that Dutch astronomer Jan Oort had observed, and together their work laid the foundation for modern understanding of galactic dynamics.

Lindblad served as the director of the Stockholm Observatory in Sweden, where he conducted much of his influential research on galactic structure and rotation. He held this position for decades and was a leading figure in Swedish and European astronomy during the first half of the 20th century.

Lindblad's theory of differential galactic rotation independently complemented Oort's observational work on stellar motions, and their combined findings are often discussed together in astronomy. Oort later developed the mathematical formulations known as the Oort constants, which quantified the differential rotation that Lindblad had first proposed.

Bertil Lindblad lived from 1895 to 1965, with his most influential work on galactic rotation published in the mid-1920s. He was active during a transformative period in astrophysics when the true scale and structure of the Milky Way galaxy were first being understood.