Swedishastronomer. His early work on luminosity criteria made possible a photometric survey which revealed the distribution of stars in the Sun's part of the Galaxy. He went on to study stellar statistics and dynamics on an increasingly larger scale, and showed how J. C. Kapteyn's discovery of two star streams provided evidence that the entire Galaxy was rotating, with differential rotation (soon confirmed by J. H. Oort). Lindblad also showed that the Galaxy is a spiral, and went on to study the dynamics of other galaxies, discovering what is now called Lindblad resonance. In the 1940s he proposed the density wave theory to explain spiral structure. In his galactic work he was aided by his son Per Olof Lindblad (1927– ).
Subjects: Astronomy and Astrophysics.