Aurora Borealis

An aurora is a polar regions natural light display, caused by the collision of charged particles directed by the Earth’s magnetic field. An aurora typically occurs in the ionosphere and is usually observed at night. It is also referred to as a polar aurora or as polar lights. In northern latitudes the effect is known as the aurora borealis or the northern lights and in southern counterpart it has another name: aurora australis or the southern lights.

Auroras do occur deeper inside the polar regions, but these are infrequent and often invisible to the naked eye.

These phenomena are commonly visible between 60 and 72 degrees north and south latitudes, which place them in a ring just within the Arctic and Antarctic polar circles.

Auroras result from emissions of photons in the Earth’s upper atmosphere, above 50 miles (80 km), from ionized nitrogen atoms regaining an electron, and oxygen and nitrogen atoms returning from an excited state to ground state.

Auroras are much more than just pretty lights in the sky. Underlying each display is a potent geomagnetic storm with possible side-effects ranging from satellite malfunctions in orbit to power outages on terra firma. Telecommunications, air traffic, power grids and GPS systems are all vulnerable.