Carl Friedrich von Weizsäcker (born 28.06.1912) is a German theoretical physicist and astrophysicist and a member of the Göttingen Academy of Sciences. He was born in Kiel. He graduated from the University of Leipzig (1933), where he worked; in 1936 —41 he was at the Kaiser Wilhelm Institute of Physics in Berlin, in 1942 — 45 professor at the University of Strasbourg and in 1946 —57 head of a department of the M. Planck Institute of Physics in Göttingen. In 1957 —69 he was professor at the University of Hamburg, and from 1970 director of an institute in Starnberg.
His research concerned atomic and nuclear physics, quantum theory, unified field theory, astrophysics, cosmology, the theory of the formation of the Solar System and of the galaxies, and the evolution of stars. He proposed (1935) a semi-empirical formula for the binding energy of the nucleus (the Weizsäcker formula). He laid the foundations of the theory of the isomerism of atomic nuclei (1936). Independently of H. Bethe he discovered in 1938 — 39 the carbon-nitrogen cycle. In quantum electrodynamics he is known for the method of equivalent photons (the Weizsäcker–Williams method). He was the author of a hypothesis of the formation of the planetary system (1944).