Lynden-Bell, Donald (1935– )

English astrophysicist known for his significant contributions to the theories of star motions, the formation of the Galaxy, spiral structure in galaxies, chemical evolution of galaxies, and the distributions and motions of galaxies and quasars. In 1969 he proposed that black holes are at the centres of galaxies and provide the energy sources for quasars.

Lynden-Bell was born in Dover, Kent, and studied at Cambridge. After two years at the California Institute of Technology and Hale Observatories, he returned to Cambridge, where in 1972 he became professor and director of the Institute of Astronomy.

His 1962 paper with US astronomers Olin Eggen and Allan Sandage, proposing that the Galaxy formed in a free-falling collapse, has stimulated an enormous amount of research. In 1969 Lynden-Bell proposed that quasars were powered by massive black holes. Later, continuing this line of thought, he postulated the existence of black holes of various masses in the nuclei of individual galaxies. The presence of these black holes would account for the large amounts of infrared energy that emanate from a galactic centre. Lynden-Bell further argued that in the dynamic evolution of star clusters, the core of globular star clusters evolves independently of outer parts, and that only a dissipative collapse of gas would account for that evolution.