Atomic Bombs, Asteroids and JFK: The Wild Ideas of Physicist Luis Alvarez

Luis Alvarez was an expert in physics, but that didn't stop him from digging into paleontology and solving a couple of mysteries. Bettmann/Getty Images
Luis Alvarez was an expert in physics, but that didn't stop him from digging into paleontology and solving a couple of mysteries. Bettmann/Getty Images

Many people would like to be remembered for doing something cool, like forming a leading geologic theory, winning the Nobel Prize, or even helping solve a lingering global mystery. But most of us won't be remembered for any of these accomplishments, because they're hard to do and require complex math and expert knowledge.

Yet Luis Alvarez did all those things and more, and Stuff You Missed in History Class hosts Holly Frey and Tracy V. Wilson recount his achievements in a two-part episode of the podcast.


Alvarez was trained as a physicist, but — as you'll soon see — he had experience in many scientific fields. He went to the University of Chicago for his undergraduate degree in physics, and stayed there to receive his master's in 1934 and doctorate in 1936. While at the university, he researched cosmic rays. And after a stint at the University of California, Berkeley as a research fellow, he moved on to the Radiation Laboratory at the Massachusetts Institute of Technology.

By the time World War II came around, he had helped develop some seriously useful radar tools, including a system that made it possible to detect aircraft when it was too overcast to see them, and one that allowed Allied planes to evade U-boats' radar-warning receivers and destroy the surfaced submarines.

But in 1943, Alvarez heeded a different wartime calling when he joined the Manhattan Project, the U.S. research and development program for atomic warfare weapons. Alvarez eventually helped create the detonators for the "Fat Man" atomic bombs, and he was on the aircraft Enola Gay when it dropped the "Little Boy" bomb on Hiroshima, Japan.

Although he contributed to the nuclear bombs, Alvarez did have some misgivings about their devastating effects. "Like many of the scientists who worked on the Manhattan Project, Luis was really horrified by the level of destruction and death that the atomic bombs had the power to cause," says Tracy. "But since World War II ended so quickly after the second one was dropped, he really had no doubt the United States had done the right thing."

After the war, Alvarez went back to Berkeley and studied bubbles. OK, perhaps the research was a bit more complicated: He studied particle physics, using a liquid hydrogen bubble chamber he developed to discover a load of resonance particles. In fact, the work was complicated enough to earn him a Nobel Prize in 1968.

And if that isn't impressive enough, Alvarez also used physics to study the John F. Kennedy assassination (his conclusion was roughly "sorry folks, no conspiracy to see here") and searched for hidden chambers in an Egyptian pyramid using cosmic rays. And perhaps more famously, he hypothesized that dinosaurs were wiped out by an asteroid and the consequential decrease of solar radiation.

Alvarez's son, Walter, was a geologist who discovered a layer of clay in the earth with extremely high levels of the element iridium. Iridium is not common on Earth, but is common in extraterrestrial objects. In a 1980 paper in the journal Science, the father-son duo and other scientists proposed that a giant asteroid hit Earth, ending the Cretaceous period and wiping out loads of species from the planet. That hypothesis seemed crazy at the time, but grew in popularity as the site of the Chicxulub crater (where the asteroid crashed into Earth) was found and more data was gathered on the extinction event.

But those are just the basics of Luis Alvarez's scientific exploits. Join Tracy and Holly as they explain his discoveries and contributions on this in-depth, two-part episode of Stuff You Missed in History Class.