Our Magnetic Earth (book review)

Title : Our Magnetic Earth – The science of Geomagnetism.
Author ; Ronald T. Merrill
Published ; University of Chicago press, Chicago & London, 2010
Size; Hard cover, 227 pages & notes + index.

Comment.
An excellent science book wherein he gives basic theory with simple analogies, but excludes the maths. Starts out explaining magnetism, moves onto magnetism in the rocks, magnetic reversals then the source of earths magnetic field and briefly touches on other planets magnetic fields. Then looks at the Sun’s magnetic field along with sunspots, solar wind etc. He then steps sideways to look at animals interaction with magnetic field, and then global weather.
Throughout the book he sticks closely to his science, with occasional snippets about the people behind the science, and some of the theories that have been dis-proven / now out of favor. He also reminds us that science theories can be incorrect and to think for ourselves.
This has answered more than the questions I had lingering since I graduated from geology- indeed many of the findings have been developed relatively recently.
• The source of the Earth’s magnetic field is now considered to be a “dynamo” of liquid iron under super pressure about the Earth’s outer core.
• Magnetic reversals take about 1,000 – 10,000 years to happen, and the Earth’s magnetic field is reduced to about ¼ of present during such periods.