Public Lecture by Professor Jeremy Bloxham
There will be a public lecture by Professor Jeremy Bloxham from Harvard University titled "Solar System Planetary Magnetic Fields". It will be held at Lecture Theatre 31, Block S16, Level 3, NUS Faculty of Science, Lower Kent Ridge Road, on 23 Apr 09 at 6:00pm.
The planets in our Solar System exhibit a wide range of magnetic fields. Earth and the gas giants Jupiter and Saturn have strong, predominantly dipolar magnetic fields. The ice giants Uranus and Neptune have strong but highly non-dipolar fields. Mercury has a weak field, Mars an extinct field, and Venus no field.
Magnetic fields are generated by dynamo action in electrically-conducting, convecting regions in a planetís interior. This dynamo action can be investigated both experimentally and numerically. The last decade has seen great advances in numerical models of dynamo action, but they still operate in a numerical regime that is far from that which is appropriate. Given the limitations of the numerical models we ask whether the gross differences that we see between the magnetic fields of the different planets can be explained by the gross differences in those planetsí internal structure. We also examine the critical role of observations, and the constraints that observations can place on dynamo theory.
Geophysicist Professor Jeremy Bloxham is Dean of Science in Harvard Universityís Faculty of Arts and Sciences (FAS), Mallinckrodt Professor of Geophysics, and professor of computational science in Harvardís School of Engineering and Applied Sciences. He was first appointed to the Harvard faculty as an assistant professor in 1987, promoted to full professor in 1993 and assumed the Mallinckrodt chair in 2005. In 2002, he was named a Harvard College Professor, a distinction recognizing exceptional undergraduate teaching. Prof Bloxham studies how planets generate magnetic fields, a long-recognized dynamic phenomenon that is still not fully understood despite more than four centuries of scientific investigation. His research group has developed a three-dimensional numerical model that could help explain why the Earthís magnetic field has weakened by as much as 10 percent over the past 150 years. Other interests include the application of high-performance computing and visualization to problems in geophysics. Prof Bloxham holds a B.A. and an M.A. in Mathematics from Cambridge University awarded in 1982 and 1986 respectively, and a Ph.D. in Geophysics awarded by Cambridge University in 1986. He is a fellow of the Royal Society, Royal Astronomical Society, and the American Geophysical Union, and a member of both the American Association for the Advancement of Science and the Society for Industrial and Applied Mathematics. He has served on the editorial boards of the Journal of Geophysical Research and Geophysical Journal International and has received professional honors including a Packard Foundation Fellowship in 1990, the Presidential Young Investigator Award in 1991, the Macelwane Medal of the American Geophysical Union in 1994, and the Chapman Medal of the Royal Astronomical Society in 2001.