Manuel Sandoval Vallarta

Mexican physicist and Physics professor at both MIT and the Institute of Physics at the National Autonomous University of Mexico (UNAM). He received his B.S. in physics from MIT in 1921; in 1924, MIT awarded him his Ph.D. He joined MIT's physics faculty in 1923, eventually rising to the rank of full professor. In 1927, Vallarta received a two-year Guggenheim Fellowship to study physics in Germany. The Universities of Berlin and Leipzig hosted him, and he was able to learn from Albert Einstein, Max Planck, Erwin Schrödinger, and Werner Heisenberg. While at MIT, Vallarta was a mentor to Richard Feynman and Julius Stratton. With Georges Lemaître, a Belgian physicist and churchman, Vallarta discovered that the intensity of cosmic rays varied with latitude because these charged particles are interacting with the Earth's magnetic field. They also worked on a theory of primary cosmic radiation and applied it to their investigations of the sun's magnetic field and the effects of the galaxy's rotation. While at UNAM, he worked with Luis Alvarez and Arthur Compton on experiments to show that cosmic rays were composed of protons. Manuel Sandoval Vallarta died on 18 April 1977, aged 79, in Mexico City. Link to Wikipedia biography