Earth

Earth’s magnetic field is generated by motion in its electrically conducting outer core. The field shapes the planet’s interaction with the solar wind, while auroras reveal some of the resulting particle motion. Measurements combine signals from the core, crust, ionosphere and even moving ocean water. ESA’s Swarm mission helps separate those contributions, making the field a tool for investigating processes both above and below the surface.

Mean diameter

12,742 km

Rotation

23 h 56 min

Year

1 Earth year