US astrophysicist who developed influential theories about the formation of stars and planetary systems.
Spitzer was born in Toledo, Ohio, and studied at Yale, with a year in the UK at Cambridge. He stayed at Yale until 1947, when he moved to Princeton as head of the Astronomy Department.
Spitzer proposed that only a magnetic field could contain gases at temperatures as high as 100 million degrees, by which point hydrogen gas fuses to form helium, and he devised a figure-of-eight design to describe this field. His model was important to later attempts to bring about the controlled fusion of hydrogen.
Spitzer criticized the theory that our planetary system is the result of a gas cloud or gaseous filaments breaking off from the Sun to become planetary fragments. He showed that a gas would be dispersed into interstellar space long before it had cooled sufficiently to condense into planets.