AURORA
A luminous phenomenon due to electrical discharges in the atmosphere; probably confined to the thin air of high altitudes . Most commonly seen in sub-Arctic and sub- Antarctic latitudes, it is called Aurora Borealis or Aurora Australis, according to the hemisfere whre it occurs. Observations with the spectroscope indicate that a faint "permanet aurora" is a normal feature of the sky in all parts of the world. The sporadic visible emission from the upper atmosphere over middle and high latitudes. Also called "northern lights".