Our Magnetic Earth

For the general public, magnetism often seems more the province of new age quacks, movie mad scientists, and grade-school teachers than an area of actual, ongoing scientific inquiry. But as Ronald T. Merrill reveals in Our Magnetic Earth, geomagnetism really is an enduring, vibrant area of science, one that offers answers to some of the biggest questions about our planet’s past—and maybe even its future. In a clear and careful fashion, he lays out the physics of geomagnetism and magnetic fields, then goes on to explain how Earth’s magnetic field provides crucial evidence for our understanding of continental drift and plate tectonics; how and why animals, ranging from bacteria to mammals, sense and use the magnetic field; how changes in climate over eons can be studied through variations in the magnetic field in rocks; and much more. Throughout, Merrill peppers his scientific account with bizarre anecdotes and fascinating details, from levitating pizzas to Moon missions to blackmailing KGB agents—a reminder that real science can at times be stranger, and more amusing, than fiction. A winning primer for anyone who has ever struggled with a compass or admired a ragged V of migrating geese, Our Magnetic Earth demonstrates that education and entertainment need not be polar opposites.

An introductory guide to global magnetic field properties, Earth Magnetism addresses, in non-technical prose, many of the frequently asked questions about Earth's magnetic field. Magnetism surrounds and penetrates our Earth in ways basic science courses can rarely address. It affects navigation, communication, and even the growth of crystals. As we observe and experience an 11-year solar maximum, we may witness spectacular satellite-destroying solar storms as they interact with our magnetic field. Written by an acknowledged expert in the field, this book will enrich courses in earth science, atmospheric science, geology, meteorology, geomagnetism, and geophysics. Contains nearly 200 original illustrations and eight pages of full-color plates. * Largely mathematics-free and with a wide breadth of material suitable for general readers* Integrates material from geomagnetism, paleomagnetism, and solar-terrestrial space physics.* Features nearly 200 original illustrations and 4 pages of colour plates

The Earth's Magnetic Field : Its History, Origin, and Planetary Perspective

The Hidden Link Between Earth’s Magnetic Field and Climate offers a new framework of understanding and interpretation for both well-known and less known relations between different geophysical and meteorological variables which can improve the quality of climate modeling. The book reviews the most current research on both current and paleo data to introduce a causal chain of interactions between the geomagnetic field, energetic particles which bombard the Earth’s atmosphere, ozone and humidity near the tropopause, and surface temperature. The impacts of these complicated interactions is not uniformly distributed over the globe, thus contributing to our understanding of regional differences in climatic changes and the asymmetrical ozone distribution over the globe. Covers the newly discovered autocatalytic cycle for ozone production in the lower stratosphere, providing a better understanding of the heterogeneous distribution of ozone globally Outlines a mechanism for the lower stratospheric ozone influence on the temperature and humidity of the upper troposphere Provides a single resource on research in energetic particles’ modulation by heterogeneous geomagnetic fields, mechanisms of the influence of particles on the atmospheric ozone, and the influence of ozone on climate

The Old Theory Until now, there was only one theory regarding the source of Earth's magnetic field, which is the internal dynamo theory. This theory was accepted because it offered the best explanation at the time. Also, much research has been done to support the theory. According to the internal dynamo theory, a dynamo near the center of the planet generates the current that produces the magnetic field. This dynamo would be in the liquid outer core of the planet. It would produce the magnetic axis and project it from the planet. The axis would expand and spread the magnetic field around the planet. This theory also suggests that the internal dynamo is sustaining itself by using fuel from Earth's core. The internal dynamo theory has changed over the years. At first scientists thought that a bar magnet was in the center of the planet and the compass needle pointed to the poles of that magnet. This made perfect sense at the time because we can see that the same thing happens when we put a compass near a bar magnet. The Bar Magnet In The Sun image demonstrates the idea of the bar magnet theory. However, this example shows the bar magnet imbedded within the sun because just like the planets, the sun also has a magnetic field, which is more complex than Earth's magnetic field. Scientists have tried to use the internal dynamo theory to explain the magnetic fields of all the planets, some moons, and the sun. However, the old model does not work for the sun, moon, and other planets. The bar magnet concept lasted a long time as the main theory regarding the source of Earth's magnetic field. However, while trying to apply it to other cases, scientists found problems with the theory. Over the years, they discovered that a bar magnet could not hold magnetism above the temperature of 770 degrees centigrade because high heat destroys magnetism. This caused the theory to gradually evolve over time.

Topics involved in studies of the Earth's magnetic field and its secular variation range from the intricate observations of geomagnetism, to worldwide studies of archeomagnetism and paleomagnetism, through to the complex mathematics of dynamo theory. Traditionally these different aspects of geomagnetism have in the main been studied and presented in isolation from each other. This text draws together these lines of inquiry into an integrated framework to highlight the interrelationships and thus to provide a more comprehensive understanding of the geomagnetic field.