Phenomena : Aurora Australis

This view of the Aurora Australis, or Southern Lights, which was photographed by an astronaut aboard Space Shuttle Discovery (STS-39) in 1991, shows a spiked band of red and green aurora above the Earth's Limb. Calculated to be at altitudes ranging from 80 - 120 km (approx. 50-80 miles), the auroral light shown is due to the "excitation" of atomic oxygen in the upper atmosphere by charged particles (electrons) streaming down from the magnetosphere above.

Looking at the auroras from space, they look like almost circular bands of light around the North and South Poles. At the North Pole, it's called aurora borealis, or northern lights, and at the South Pole it's called the aurora australis, or southern lights.

According to scientists, the main cause behind the differences in location appears to be what occurs between the solar wind and Earth's magnetic field. These circular bands of aurora shift in opposite directions to each other depending on the orientation of the sun's magnetic field, which travels toward the Earth with the solar wind flow. They also noted that the auroras shift in opposite directions to each other depending on how far the Earth's northern magnetic pole is leaning toward the sun.

Photo : NASA Space Shuttle Discovery (STS-39) 1991

Phenomena