Swiss astronomer who predicted the existence of neutron
stars 1934. He discovered 18 supernovae and determined that cosmic rays
originate in them.
Zwicky observed that most galaxies occur in clusters, each of which
contains several thousand galaxies. He made spectroscopic studies of
the Virgo and Coma Berenices clusters and calculated that the distribution
of galaxies in the Coma Berenices cluster was statistically similar
to the distribution of molecules in a gas when its temperature is at
equilibrium. Beginning 1936, he compiled a catalogue of galaxies and
galaxy clusters in which he listed 10,000 clusters.
Zwicky was born in Varna, Bulgaria, but his parents were Swiss and he
retained his Swiss nationality throughout his life. He studied at the
Federal Institute of Technology in Zürich, then moved to the USA
1925 to join the California Institute of Technology, where he spent
his whole career.
Zwicky was among the first to suggest that there is a relationship between
supernovae and neutron stars. He suggested in the early 1930s that the
outer layers of a star that explodes as a supernova leave a core that
collapses upon itself as a result of gravitational forces.