T. Rex and the Crater of Doom

American geologist Walter Alvarez (born in 1940) is best known for his theory that an asteroid impact triggered the mass extinction of the dinosaurs. He earned his bachelor of science degree at Carleton College and completed his PhD in geology at Princeton University. After years of work in the private sector, Alvarez worked as a research scientist for Columbia University and then as a professor at the University of California, Berkeley. While researching plate tectonics in Gubbio, Italy, Alvarez became interested in the KT boundary: the rock layer that marks the end of the Cretaceous period and the beginning of the Tertiary period. The sudden shift in materials and fossils in the rock convinced Alvarez that a mass extinction had occurred quite abruptly, and he hypothesized that a catastrophic event, such as an asteroid impact, could be the cause.

Along with his father, Luis W. Alvarez, and many colleagues, Alvarez worked for more than a decade to prove his impact hypothesis. This research took him from Italy to Denmark and then to Mexico, sampling rocks from the KT boundary layers and trying to understand how and where an asteroid impact may have occurred. His book reveals his professional highs and lows during this quest, detailing how he followed the rock’s clues before finally identifying the