When speaking of magnetism, the first thing that comes to mind is a compass. To a layman, a compass appears simple though mysterious in its directive ability to navigate, but to a sailor, a compass is an icon of safety and also a symbol representing the quest for new destinations. A compass works because the Earth also acts like a giant magnet! The field of geomagnetism and its complex nature has long puzzled and intrigued man. Earth's magnetic field, also known as the geomagnetic field originates in its core, and its study, ‘geomagnetism’, analyzes such dynamics of the Earth’s magnetic field.
The distribution and variations of geomagnetism are not only a result of the happenings in the Earth's interior and its atmosphere but also because of the larger solar and cosmic phenomena. We may well agree with Humboldt (the greatest explorer-scientist of the eighteenth and early nineteenth centuries) that "Nothing that occurs in our planet can be supposed to be independent of cosmical relations." So how does the Earth’s magnetic field operate and has this field changed over time? What is the phenomenon of geomagnetic reversal? If such a thing were to happen in the near future, how will it affect life on Earth? Read this engrossing module to delve deeper into the mysteries of the universe.