Erdmagnetfeldrichtungen

Earth's magnetic field, also known as the geomagnetic field (in German discussions often referred to as Erdmagnetfeld), is the planetary magnetic field that surrounds Earth and extends from its interior into space. Its dominant component is a dipole-like field, though the actual field is offset from the planet’s center and evolves over time. The field is generated by the geodynamo: convection of liquid iron in the outer core combined with Earth's rotation, which sustains electrical currents that produce the magnetic field.

At the surface, field strength ranges roughly from 25 to 65 microteslas (0.25 to 0.65 gauss). The field undergoes secular variation, a slow but continuous change in intensity and direction. Magnetic poles wander over time; in recent decades the magnetic north has moved rapidly across the Arctic.

The magnetosphere is the region of space dominated by Earth’s magnetic field, acting as a shield against charged solar wind particles. Interactions with the solar wind create structures such as the bow shock and magnetopause and drive phenomena like auroras in high-latitude regions. Strong solar activity can compress the magnetosphere, increasing radiation exposure to satellites and the upper atmosphere.

Polarity reversals have occurred irregularly in Earth’s history, typically over hundreds of thousands of years. The last reversal, the Brunhes–Matuyama boundary, occurred about 781,000 years ago. Paleomagnetism in rocks and sediments preserves records of past field directions, aiding studies of geologic processes and plate tectonics.

Modern measurements from ground observatories and satellites (for example, the Swarm mission) continuously monitor the field to support navigation, protect infrastructure, and improve models of the geodynamo.