P. M. MathewsP. M. Mathews served as Senior Professor of Theoretical Physics at the University of Madras in India, and is now retired. His main research interests are in the Earth's nutation and precession, and other concomitant phenomena, as well as the propertis of, and processes in, the Earth's deep interior. Professor Mathews is the lead originator of the Mathews-Herring-Buffett (MHB) theory of nutation adopted by the International Astronomical Union and International Union of Geodesy and Geophysics. In recognition of his work on the MHB model of nutation, he was elevated to the Fellowship of the American Geophysical Union (2004). He was elected as a Fellow of the Indian Academy of Sciences in 1975 and of the Indian National Science Academy in 1983. He has published 120 papers in reputable journals. Read More Read Less