Bruno Rossi, 88, Pioneer in Cosmic Ray Research
by Wolfgang Saxon
THE NEW YORK TIMES OBITUARIES
Wednesday, November 24, 1993
Dr. Bruno Rossi, an authority on cosmic rays and a retired professor of physics at the
Massachusetts Institute of Technology, died on Sunday at his home in Cambridge, Mass. He
The cause was cardiac arrest, M.I.T. said.
Much honored for his own explorations, Dr. Rossi had a hand in the development of space
physics and in shaping public policy for space exploration. His investigations of cosmic
rays and their interactions with matter laid the foundation for high-energy particle
Cosmic rays are atomic particles that bombard Earth's atmosphere from space at speeds
approaching that of light.
Professor Rossi came to M.I.T. from the Los Alamos Laboratory in 1946 as a professor of
physics. In 1966 he was named Institute Professor, a rank reserved for scholars of special
distinction. He retired in 1971.
`One of the Giants'
Prof. Claude R. Canizares, director of M.I.T. Center for Space Research, Dr. Rossi's
old workplace, called him ``one of the giants of modern physics and astrophysics.''
He said that even before joining M.I.T., Professor Rossi had made ``seminal
contributions'' and invented basic experimental techniques used in every major laboratory
to this day. At M.I.T. he ``opened new windows on the universe,'' he added.
``He is rightfully called the grandfather of high-energy astrophysics, being largely
responsible for starting X-ray astronomy as well as the study of interplanetary plasma,''
Professor Canizares said. And he called Professor Rossi's textbooks models of clarity.
Professor Rossi was the author or co-author of seven books and more than 100 technical
articles. His autobiography, ``Moments in the Life of a Scientist,'' was published by
Cambridge University Press in 1990. As a teacher, he inspired leaders in higher learning
Dismissed by Fascists
Bruno Benedetto Rossi was born in Venice, the son of an electrical engineer. He studied
at the University of Padua and received his doctorate in physics at the University of
Bologna in 1927. He started his academic career at the University of Florence and held the
chair in physics in Padua from 1932 to 1938, when the Fascist regime dismissed him.
He then spent short periods in Copenhagen; Manchester, England; and Chicago, and joined
the faculty of Cornell University in 1940. From 1943 to 1946 he was on the staff of the
Los Alamos Laboratory in New Mexico, where the atomic bomb was developed.
Dr. Rossi's career paralleled the evolution of cosmic-ray physics. He ventured into
that mysterious field in 1929. That year he devised the first of the instrumental
techniques he contributed to astrophysics.
Known as the Rossi coincidence circuit, it recorded the simultaneous occurrence of
three or more electrical pulses. It became a fundamental electronic device for
experimental high-energy nuclear physics and a basic element of modern computers.
In 1931 he discovered that cosmic-ray particles,thought rapidly losing energy, could
pass through enormous thicknesses of matter --- up to a meter of lead. He also discovered
that individual cosmic rays, colliding with atoms, often generated large numbers of
secondary particles, known as showers. His findings gave evidence of the astonishing
energies associated with cosmic rays.
His interest in this bombardment from space led him into space research as the
technical means for placing instruments outside the Earth's atmosphere became available.
In 1958, for instance, he focused attention on direct measurements of ionized
interplanetary gas by space probes.
He and his colleagues built a detector with which the Explorer X satellite in 1961
discovered the magnetopause, the space boundary beyond which Earth's magnetic field loses
its dominance. He also initiated the exploratory search for cosmic x-rays that in 1963
resulted in the discovery of the strong Scorpio X-ray source, the first such source to be
observed outside the solar system.
The discovery marked the beginning of X-ray astronomy, which soon became a principal
tool of astrophysics research.
Dr. Rossi was a member of many scientific societies, including the National Academy of
Sciences and American Academy of Arts and Sciences. His honors included the United States
Medal of Science, the Gold Medal of the Italian Physical Society, the Elliot Cresson Gold
Medal and the Wolf Prize in Physics.
Dr. Rossi is survived by his wife Nora Lombroso Rossi; two daughters, Florence Moloney
of Sunnyvale, Calif. and Linda Rossi of Manhattan; a son Frank of Boston, and two