“The most striking impression was that of an overwhelming bright light. I had seen under similar conditions the explosion of a large amount—100 tons—of normal explosives in the April test, and I was flabbergasted by the new spectacle. We saw the whole sky flash with unbelievable brightness in spite of the very dark glasses we wore. Our eyes were accommodated to darkness, and thus even if the sudden light had been only normal daylight it would have appeared to us much brighter than usual, but we know from measurements that the flash of the bomb was many times brighter than the sun. In a fraction of a second, at our distance, one received enough light to produce a sunburn. I was near Fermi at the time of the explosion, but I do not remember what we said, if anything. I believe that for a moment I thought the explosion might set fire to the atmosphere and thus finish the earth, even though I knew that this was not possible. ”
born: February 1, 1905 Tivoli, Italy
died: April 22, 1989 Lafayette, California
Italian physicist who used to be cowinner, with Owen Chamberlain , of the Nobel Prize for Physics in 1959 for the discovery of the antiproton, an antiparticle having the identical mass as a proton however opposite in electrical charge.In 1932 Segrè used to be appointed assistant professor of physics on the University of Rome, and two years later he participated in neutron experiments directed by Fermi, during which many parts, including uranium, had been bombarded with neutrons, and elements heavier than uranium were created. In 1935 they discovered slow neutrons, which have properties essential to the operation of nuclear reactors.Segrè left Rome in 1936 to become director of the physics laboratory on the University of Palermo. Twelve months later he discovered technetium, the primary man-made element not present in nature.Persevering with his analysis, he and his associates discovered the element astatine in 1940, and later, with another team, he discovered the isotopeplutonium-239, which he discovered to be fissionable, very similar to uranium-235. Plutonium-239 used to be used in the first atomic bomb and in the bomb dropped on Nagasaki.He wrote a number of books, including Experimental Nuclear Physics (1953), Nuclei and Particles (1964), Enrico Fermi: Physicist (1970), and two books on the history of physics, From X-rays to Quarks: Modern Physicists and Their Discoveries (1980) and From Falling Bodies to Radio Waves (1984).
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