Widnes SciBar @ the Hillcrest Hotel

Widnes Scibar

Earth’s Magnetic Reversals

Hillcrest Hotel, Cronton Lane
Widnes, WA8 9AR
7.30 pm, Wednesday 10th April 2019

Richard Holme, Professor of Geomagnetism, University of Liverpool

The strength of the geomagnetic field was first measured directly in 1833. Since this time, the large-scale structure of the field has been decreasing, leading to  suggestions that we may be observing a geomagnetic reversal. Certainly, every time a new model of the geomagnetic field is made available, this is the angle that excites the press! Current global decay is dominated by the growth of a feature called the South Atlantic Anomaly (SAA) – an area of weakening field currently centred around Brazil.

It is not possible to predict field evolution, but we might get an idea of whether this SAA will lead to a full reversal by looking at past records of the field,  particularly for times of a reversal, or an excursion (which can be characterised as an “almost reversal”). The most recent such events are the Laschamp and Mono Lake events, dating from 30,000 – 45,000 years ago. A new model of these excursions suggests not SAA-like behaviour, but decay over the whole Earth.

SciBar – Talking science in a relaxed setting
What is it? – Talks about science, research and policy which you can discuss and question
Where is it? – usually at the Hillcrest Hotel, Cronton Lane, Widnes WA8 9AR, but at other venues occasionally
Who is it for? – Widnes SciBar is for anyone with an interest in science, or a wish to know more about science