Walter Alvarez

person · earth

American geologist whose fieldwork on the Cretaceous–Palaeogene boundary section at Gubbio led, with his father the physicist Luis Alvarez and the Berkeley nuclear chemists Frank Asaro and Helen Michel, to the 1980 proposal that a large asteroid impact caused the extinction. The collaboration is worth attending to as a piece of scientific method: the geological question was Walter's, the idea of using iridium as a chronometer was Luis's, and the measurement capability was Asaro and Michel's neutron-activation laboratory. None of the four could have produced the result alone, and the hypothesis was resisted for most of the following decade by parts of the palaeontological community, partly on the reasonable ground that the fossil record around the boundary appeared to show a more gradual decline than an instantaneous catastrophe implies. Alvarez later wrote a first-hand account of the episode in T. rex and the Crater of Doom (1997).

A person is not a place. Drawing it on a map would assert something about the world that no stored fact supports.