The Van Allen belts are two rings of electrically charged particles that encircle our planet. The belts are shaped like fat doughnuts, widest above Earth’s equator and curving downward toward Earth’s surface near the polar regions. These charged particles usually come toward Earth from outer space—often from the Sun—and are trapped within these two regions of Earth’s magnetosphere.

Since the particles are charged, they spiral around and along the magnetosphere’s magnetic field lines. The lines lead away from Earth’s equator, and the particles shuffle back and forth between the two magnetic poles. The closer belt is about two thousand miles (three thousand kilometers) from Earth’s surface, and the farther belt is about ten thousand miles (fifteen thousand kilometers) away.