Alvarez was born in San Francisco, California, on June 13, 1911. He attendedthe University of Chicago, where he received his bachelor's degree (1932), master's degree (1934) and doctorate (1936). Upon graduation, he joined the faculty at the University of California at Berkeley. He became professor of physics there in 1945 and served in that capacity until 1978. Because of his wide-ranging interests, Alvarez was called the "prize wild-idea man " by colleagues at Berkeley. His earliest research was in the area of nuclear physics andcosmic rays. He was involved in research on the "east-west" effect in cosmicrays, the radioactivity of tritium (hydrogen-3) and other isotopes, the nature of nuclear fission, and the magnetic properties of the neutron. Alvarez received the Nobel Prize for physics in 1968 for his work on liquid-hydrogen bubble chambers. After Donald Glaser's invention of the bubble chamber in 1952,scientists attempted to construct larger, more efficient models of the detecting device. Alvarez and his colleagues were at the forefront of this research. In 1959, his research team completed a 72-inch (183 cm) chamber that was, for five years, the largest of its kind in the world. At the same time, Alvarez worked on improving methods for analyzing photograph s obtained in the bubble chamber. He realized that existing methods were too slow to observe and record particles with very short lives. As a result of improved computing and analytical techniques, Alvarez and his colleagues were eventually able to discover a number of very short-lived particles, known as resonances, withlifetimes of less than 10-20 second. During World War II, Alvarez was actively involved in research on the atomic bomb and radar. Working with Lawrence Johnston, he developed a narrow-beam ground-based radar system that permittedairplanes to land in fog and bad weather. He also developed a system for "blind" bombing of targets. In 1980, Alvarez and his son proposed a theory regarding the extinction of dinosaurs that occurred 65 million years ago. Thewy haddiscovered a layer of sedimentary rock in Italy that is unusually rich in iridium. Similar iridium-rich strata were later found in other parts of the world. Alvarez and his son suggested that the iridium came from a giant meteorite that collided with the Earth 65 million years ago. The dust produced by thecollision, they said, blocked out solar radiation for three years and destroyed so much vegetation that dinosaurs became extinct.