Aurora borealis聽or聽avr贸ra is the radiance of visible light in the upper atmosphere, visible at night.聽This wonderful natural phenomenon was聽probably named聽aurora borealis or northern lights by the French astronom Pirre Kasenti in 1621 after the Roman goddess of the morning dawn Aurora.聽It was described long before him by Aristotle and Pliny聽.聽The aurora borealis is described in various myths of Scandinavian nations and Eskimos, where it has a supernatural meaning.聽In the southern hemisphere, the same phenomenon is observed, British explorer James Chooche observed it in the southern Indian ocean and in 1773 named it aurora australis.
The aurora borealis is most commonly seen in two oval bands around the earth’s magnetic poles, at an approximate “magnetic latitude” of 70 degrees. It occurs at an latitude of about 100 km (thermosphere聽).聽In areas below the oval band, aurora borealis can be seen almost every clear night.聽At mid-latitudes, aurora borealis is very rarely seen, most often as a faint glow on the horizon toward the pole.聽On rare occasions, after very strong eruptions in the Sun,聽an oval of aurora borealis descends to the south (or north in the southern hemisphere) and is then seen higher in the sky even at mid-latitudes聽.聽Best seen in autumn as well as in spring.


