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Hans Bethe - The 1987 supernova (138/158)

936 views · Published 26 June 2017 · 3:01 · Indexed 22 October 2026

Channel: Web of Stories - Life Stories of Remarkable People · 2017 · Science & Technology

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To hear more of Hans Bethe’s stories, go to the playlist: https://www.youtube.com/watch?v=LvgLyzTEmJk&list=PLVV0r6CmEsFyUDSroBQVEcbnNud7I9xom

German-born theoretical physicist Hans Bethe (1906-2005) was one of the first scientists to join the Manhattan Project, later strongly advocating nuclear disarmament. In 1967, he was awarded the Nobel Prize in Physics for his theory of stellar nucleosynthesis. [Listener: Sam Schweber; date recorded: 1996]

TRANSCRIPT: That supernova could be observed in all details, and it is still being followed. It now emits mainly infrared radiation. It could be followed in all details, close enough in fact that you could determine how much energy is given to the ejected material and that energy is a few times 1051 erg or, well, between one and two times, and only a small fraction of that, only about 1% of that comes out as light. The main part of that comes out simply as kinetic energy, so you have to observe the Doppler Effect and observe... thereby determine the velocity of the outgoing material, and from that it was possible to determine the energy release. I had some input into that, but the main analysis of that was done by one American and one Japanese astrophysicist, Woosley at University of California, and Nomoto in Tokyo University. They competed, one publishing a paper, then the other publishing a different paper and it is still going on at the present time, and they were able to analyze not only how much energy was released, but also how much nickel-56 was produced. They found out that about 7% of a solar mass of nickel-56 is produced, and that's very interesting because the nickel-56 of course, gives characteristic radiation; it contributes to the optical radiation which was visible; it contributes also gamma rays when the nickel-56 captures electrons and turns into iron-56. And... so it made us... made it possible to understand what really happens in the supernova.

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