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An aurora, or polar aurora, is a glow in the sky, seen often in a ring-shaped region around the [[magnetic pole]]s ("auroral zone") and occasionally further equatorward. The name comes from an older one, "aurora borealis," [[Latin]] for "northern dawn," given because an aurora near the northern [[horizon]] (its usual location when seen in most of [[Europe]]) looks like the glow of the sky preceding [[sunrise]]. Also known as "northern lights," although it occurs both north and south of the [[equator]].

An aurora ([[Latin]] for "dawn"), or polar aurora, is a glow in the sky, seen often in a ring-shaped region around the [[magnetic pole]]s ("auroral zone") and occasionally further equatorward. Auroras occur at both [[magnetic pole]]s 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.

The aurora is generally caused by fast [[electron]]s from space, guided earthward by magnetic field lines, and its light comes from collisions between such electrons and the [[atom]]s of the upper [[atmosphere]], typically 100 km (60 miles) above ground.

 

Charged, energized particles from the sun, called the [[solar wind]], are captured by the Earth's magnetic field.  The particles collide with [[atom]]s in the upper [[atmoshpere]], causing the [[atom]]s to become energized.  These energized [[atom]]s then release their excess energy as light. 

 

Auroras typically occur 100 km (60 miles) above ground.  

[[Category:Physics]]

[[Category:Physics]]