On this day in 1898 – February 14th – Swiss astronomer and physicist Fritz Zwicky was born in Varna, Bulgaria.

Zwicky studied physics and mathematics at the Swiss Federal Polytechnic in Zurich. In 1925 he immigrated to the United States to work with Robert Andrews Millikan at Caltech, but remained a Swiss citizen all his life. Zwicky was quite eccentric in many ways, but made important contributions in several areas of astronomy, carrying out research at both Mt Wilson and Palomar observatories.