The Aurora

An aurora is a natural light display in the sky particularly in the high latitude (Arctic and Antarctic) regions, caused by the collision of energetic charged particles with atoms in the high altitude atmosphere (thermosphere). The charged particles originate in the magnetosphere and solar wind and, on Earth, are directed by the Earth's magnetic field into the atmosphere. Most auroras occur in a band known as the auroral zone, which is typically in 3° to 6° latitudinal extent of geographical poles, or equivalently, 10° to 20° latitudinal extent of geomagnetic poles, and at all local times or longitudes. During a geomagnetic storm, the auroral zone expands to lower latitudes.

In 1621, a French scientist, Pierre Gassendi, saw the lights in the north and named after the Roman goddess of dawn, Aurora. He added the word "borealis" for the Roman god of the north wind, Boreas. These aurora borealis are also known as Northern Lights.

In the southern hemisphere, they are called aurora australis, meaning "southern." The lights are usually seen after dusk near both poles.