Wednesday 18 June 2014
An aurora is
a natural light display in the sky especially
in the high latitude regions, caused by
the collision of solar wind and magnetospheric charged particles with the high
altitude atmosphere (thermosphere). Most auroras occur in a band known as the auroral zone, which is typically 3° to 6° wide in
latitude and observed at 10° to 20° from the geomagnetic poles at all local
times (or longitudes), but often most vividly around the spring and autumn
equinoxes. The charged particles and solar wind are directed into the
atmosphere by the Earth's magnetosphere. A geomagnetic storm expands the
auroral zone to lower latitudes. Source
