报告摘要：A very close supernova explosion could have caused a mass extinction of life in Earth. In 1996, Brian Fields, the late Dave Schramm and the speaker proposed looking for unstable isotopes such as Iron 60 that could have been deposited by a recent nearby supernova explosion. A group from the Technical University of Munich has discovered Iron 60 in deep-ocean sediments and ferromanganese crusts due to one or more supernovae that exploded O(100) parsecs away about 2.5 million years ago. These results have recently been confirmed by a group from the Australian National University, and the Munich group has also discovered supernova Iron 60 in lunar rock samples and in microfossils of magnetotactic bacteria. I will discuss the data and their interpretation in terms of supernova models, and the possible implications for life on Earth.

报告人简介：John R. Ellis is currently Clerk Maxwell Professor of Theoretical Physics at King's College London. He was appointed a Commander of the Order of the British Empire(CBE) in the British Queen's 2012 Birthday Honours for services to science and technology. He was twice Deputy Division Leader for the Theory Division of CERN, and served as Division Leader for 1988–1994. He was a founding member of the LEPC and the LHCC. He is a member of the extended CLIC (Compact Linear Collider) Steering Committee and of the Coordination Group for Future Circular Collider Studies at CERN. Prof. Ellis earned his Ph.D. in theoretical particle physics in 1971 at Cambridge, UK. A world-renowned particle physicist working on collider physics and astroparticle physics, he was awarded the Maxwell Medal and Prize (1982) and the Paul Dirac Medal and Prize (2005) by the Institute of Physics. He is an Elected Fellow of the Royal Society of London since 1985 and an Elected Fellow of the Institute of Physics since 1991. He has twice won the First Award in the Gravity Research Foundation essay competition (1999 and 2005).

第207期“论坛”主请人联系方式：
何红建   62779619   hjhe@tsinghua.edu.cn