Luis Alvarez, age seventy-seven, died on August 31, 1988, after losing a battle with cancer. Alvarez had been with the Lawrence Berkeley Laboratory for thirty-five years and was responsible for the discovery of a number of subatomic particles—work for which he received the 1968 Nobel Prize for physics.
In recent years, however, he has been most noted for his research in theoretical paleontology. With his son, Walter, he propounded and popularized the idea that dinosaurs and much of the world's flora and fauna became extinct sixty-five million years ago as a result of the impact of a large asteroid or comet which created a devastating worldwide dust cloud which lowered temperatures. This hypothesis, in turn, became a major factor in the development of contemporary ideas about "nuclear winter" as a predictable result of nuclear war. The Alvarezes argued that Iridium deposits found at diverse locations around the globe dating to the end of the Cretaceous could best be explained by a single worldwide atmospheric pollution deposit of particles from outer space. The specific idea has been severely challenged, but it has set in motion an entire genre of neocatastrophist theories, from Oort Cloud to Nemesis to prehistoric acid rain as causes for dinosaur extinction. The primary critique is that species did not all go out of business within a couple of years, as the hypothesis would suggest, but rather the extinction took a very long time, even if it was accelerated. Still, the majority of paleontologists now give credence to some degree of catastrophic extinction event a la Alavarez. Bitingly critical of paleontologists who rejected his ideas, he recently commented, "I don't like to say bad things about, paleontologists, but they are not very good scientists. They're more like stamp collectors."
Earlier in his career, Alvarez developed three major radar systems, including the Ground Control Approach method of landing planes in zero visibility. In recent years, he developed the radar-mapping system used by archaeologists to probe underground features—a technique used to prove that the Pyramid of Cheops has no "secret chambers,' for example.
During World War II, he was a physicist at the Los Alamos atomic bomb project. When the bomb was actually dropped on Nagasaki in 1945, he was the only one of the scientists who flew on the mission as an observer of what they had wrought. At congressional hearings in 1953 investigating the loyalty of J. Robert Oppenheimer, director of the Los Alamos Project, Alvarez and Edward Teller agreed to testify, contrary to the advice of their superior, Ernest Rutherford. Alvarez supported Teller's advocacy of H-bomb development opposed by Oppenheimer and many others, but he said that Oppenheimer's opposition was no reflection upon his patriotism. Oppenheimer nevertheless lost his security clearance, and many scientists never forgave Alvarez for participating in the process which felled their hero.
As the inventor of hydrogen bubble chambers, now familiar to generations of students, Alvarez invented the primary way for identifying subatomic particles: their distinctive paths can be photographed and literally seen with the naked eye. Alvarez is survived by his wife and four children.