A CELEBRATION OF THE HISTORY, CULTURE, SCIENCE AND TECHNOLOGY OF RECHERCHE BAY
CSIRO Marine and Atmospheric Research Auditorium Hobart, Tasmania
26–28 February 2007

From geomancy to geodynamo: The science of magnetism and the Earth sciences
Dr Charles Barton

Charles Barton was born and educated in England, spent ten years in Africa teaching and looking for oil, then moved to Australia in 1974. He has a BSc in Physics and Mathematics (Bristol Univerisity), a Diploma in Education (University of East Africa), and a PhD in Palaeomagnetism (ANU). For most of his career, he has worked with Geoscience Australia, formerly the Bureau of Mineral Resources, in the area of geomagnetism and geohazards. In 2000 he became the first person to have visited both of the Earth’s magnetic poles. He is currently a Visiting Fellow at the Research School of Earth Sciences, Australian National University and President of the International Association of Geomagnetism and Aeronomy.

Given the historic importance of the Earth's magnetic field for navigation for 2000 years, it is small wonder that Albert Einstein declared the origin and behaviour of the geomagnetic field to be one of the seven outstanding problems in physics.

This talk traces the evolution in our understanding of the geomagnetic field from the intrigues of Chinese geomancers at the time of the Han Dynasty to high performance computer simulations of the dynamo action in the liquid core and polarity reversals.

Measurements of the strength of the Earth's field made at Recherche Bay in 1792 and 1793 during the D'Entrecasteaux Expedition were the key to demonstrating a latitude dependence of field strength that does, indeed, correspond closely to a dipolar field.

Today, high-tech alternatives have partly displaced the humble magnetic compass for direction-finding, but a knowledge of the Earth’s magnetic field remains on interest in applications ranging from dating rocks to forecasting space weather conditions.