all were studied by Berkeley physicist Luis Alvarez. Alvarez won a Nobel Prize for his discovery of new particles using a bubble chamber, but some of his fame comes from his work applying physics
principles and methods outside the normal physics-research world.
In the November issue of the American Journal of Physics, Charles
Wohl of the Lawrence Berkeley National Lab (email@example.com) looks at
three notable examples of Alvarez’s extracurricular effort.
search for possible hidden chambers in the Chephren pyramid in
Cairo-one of the three great pyramids built in the third millennium
BCE-Alvarez designed an experiment in which cosmic rays would strike
a detector set up inside a known chamber beneath the pyramid.
Observing the penetrating muons from cosmic-ray showers, this
detector would discern any intervening empty spaces in the overlying
pyramid structure. The upshot: no hidden chambers.
(2) In scrutinizing the so called “Zapruder film,” a short filmed
sequence that caught the assassination in progress, experts had been
puzzled by the backwards jerk of President Kennedy’s head after one
of the bullet impacts. Some took this to be evidence for another
assassin shooting from in front of the president’s car. Alvarez and
some of his colleagues performed impromptu experiments at a shooting
range, and also considered the conservation of momentum and the
forward-moving matter from the wound. From this they concluded that
the movie sequence was consistent with a shot coming from the rear.
(3) Most famous of all was Alvarez’s hypothesis, made in
collaboration with his son Walter Alvarez, that a thin but
conspicuous layer of the otherwise rare element iridium in numerous
places around the world, all at a geological stratum corresponding
to the era just around the boundary between the Cretaceous and
Tertiary periods (the KT boundary), signified a large asteroid
impact at that time. This impact, it was further thought, cast
enough dust into the air from a long enough time as to kill off many
living things, including a large portion of dinosaurs.