Oort Jan Hendrik

Son of a doctor, Oort studied physics at the University of Groningen in the Netherlands, where his teacher Jacobus Cornelius Kapteyn encouraged him to be an astronomer. Oort worked in Groningen and at the Yale University observatory in the United States before settling in Leiden, in the Netherlands, in 1924, where he remained for the rest of his career. With Bertil Lindblad, he discovered the rotation of our Galaxy, whose angular velocity depends on the distance to the center (differential rotation). In 1950 he took up and developed an idea of ​​Ernst Öpik’s, showing that there is a reservoir of comets between 50,000 and 150,000 astronomical units from the Sun. Oort had a major influence on the development of astronomy in the Netherlands, especially after World War II.