1979: From excess traces of iridium in late Cretaceous rocks, American scientist Luis Walter Alvarez theorizes that a large comet or asteroid struck the earth 65 million years ago, raising clouds of dust that reduced the amount od solar radiation penetrating the atmosphere and triggering the mass extinctions of dinosaurs and other Mesozoic life. Luis and Walter Alvarez at the K-T Boundary in Gubbio, Italy, 1981.
Luis Walter Alvarez 1968 Born: 13 June 1911, San Francisco, CA, USA Died: 1 September 1988, Berkeley, CA, USA Affiliation at the time of the award: University of California, Berkeley, CA, USA Prize motivation: "for his decisive contributions to elementary particle physics, in particular the discovery of a large number of resonance states, made possible through his development of the technique of using hydrogen bubble chamber and data analysis" Field: Particle physics
Mabel Alvarez, Artist; Borderline Modernist. The fine portrait shown above is a 1923 self-depiction by Mabel Alvarez (1891-1985), aunt of Luis Walter Alvarez (1911-88), winner of the Nobel Prize for Physics in 1968.