Today in astronomy history, father-son team Luis and Walter Alvarez suggest an asteroid killed the dinos.
Luis and Walter Alvarez found a band of rock rich in iridium, whose age seemed to match the extinction of the dinosaurs. Credit: Lawrence Berkeley Laboratory
“Extraterrestrial Cause for the Cretaceous-Tertiary Extinction,” by physicist Luis Alvarez, geologist Walter Alvarez, Frank Asaro, and Helen Michel, was published in Science June 6, 1980. In it, the authors propose that an asteroid crashing to Earth was responsible for the death of the dinosaurs 65 million years ago. (The timeline was later amended to 66 million years.) The suggestion is based on their discovery of an even and widespread band of sedimentary rock with unusually high levels of the rare element iridium, the remains of the atmospheric pollution from an impact eventually settling to Earth. Discovery of the Chicxulub Crater about a decade later lent credence to their theory.
