Biographical Encyclopedia of Astronomers

2014 Edition
| Editors: Thomas Hockey, Virginia Trimble, Thomas R. Williams, Katherine Bracher, Richard A. Jarrell, Jordan D. MarchéII, JoAnn Palmeri, Daniel W. E. Green

Sandoval Vallarta, Manuel

Reference work entry

BornMexico City, Mexico, 11 February 1899

DiedMexico City, Mexico, 18 April 1977

What is the origin of cosmic rays? Why do they seem to be more plentiful coming from the zenith direction at the Earth’s poles than at the equator? Massachusetts Institute of Technology professor Manual Sandoval Vallarta believed cosmic rays to be (predominantly) electrically charged. He realized that, even if electrically charged cosmic rays originate from random directions, their direction of travel will be deflected by the Earth’s magnetic field. In the 1930s, he calculated the latitudinal effect: Only the particles of greatest energy, entering the magnetosphere at the magnetic equator, will penetrate to be detected below. Yet most particles that enter at the magnetic poles will penetrate. This work was done in collaboration with  Georges Lemaître.

In 1961, he was awarded by Mexican Government with the Premio Nacional de Ciencias.

He was classmate of Robert J. Oppenheimer, and Vallarta’s most famous...

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Selected References

  1. Lemaître, G., Vallarta, M. S. (1933). “On Compton's Latitude Effect of Cosmic Radiation”, Physical Review, 43:2, pp. 87–91.Google Scholar
  2. Morse, P. M. (1977). In the Beginnings: A Physicist’s Life. Cambridge, MA: MIT Press.Google Scholar
  3. Pérez-Peraza, Jorge (2009). “Reminiscences of cosmic ray research in Mexico”, Advances in Space Research, 44:10, pp. 1215–1220.Google Scholar
  4. Sandoval Vallarta, Manuel (1940). “La radiación cósmica”, Ciencia Revista Hispano-Americana de Ciencias Puras y Aplicadas, 1:7, pp. 289–295.Google Scholar
  5. Vallarta, M. S., Feynman, R. P. (1939). “The Scattering of Cosmic Rays by the Stars of a Galaxy”, Physical Review, 55:5, pp. 506–509.Google Scholar

Copyright information

© Springer Science+Business Media New York 2014

Authors and Affiliations

  1. 1.Department of Earth ScienceUniversity of Northern IowaCedar FallsUSA