An aurora (Latin for "dawn"), or polar aurora, is a glow in the sky, seen often in a ring-shaped region around the magnetic poles ("auroral zone") and occasionally further equatorward. Auroras occur at both magnetic poles of the Earth. In the northern hemisphere, the phenomenon is referred to as the aurora borealis or the "northern lights". In the southern hemisphere, it is called the aurora australis.
Charged, energized particles from the sun, called the solar wind, are captured by the Earth's magnetic field. The particles collide with atoms in the upper atmoshpere, causing the atoms to become energized. These energized atoms then release their excess energy as light.
Auroras typically occur 100 km (60 miles) above ground.