Dutch astronomer who made fundamental contributions to the understanding of the structure and dynamics of the Milky Way. He was the first to propose the existence of dark matter based on stellar motions and predicted the Oort cloud.
Biography
He studied at the University of Groningen under Jacobus Kapteyn. He worked at Leiden Observatory, becoming its director. Awards: Bruce Medal, Gold Medal of the Royal Astronomical Society.
Key discoveries
Oort constants for differential rotation of the Galaxy.
First evidence of dark matter from stellar kinematics.
Hypothesis of the Oort cloud as the source of long-period comets.
Study of the dynamics of the Galactic center and the Crab Nebula.
💡 Oort was so fond of order that even when observing nebulae, he used the same coffee cup to estimate brightness.
"He believed the universe is defined not by our assumptions but by what we can measure."