Southern Lights (Aurora Australias): A rare video from above
Astronauts aboard the International Space Station have captured a unique perspective on the aurora australias – or Southern Lights.
The video was created from a series of still images taken on Sept. 11 as the space station passed over eastern Australia and New Zealand.
"The aurora displays a sinuous green ribbon shape – with occasional hints of red near the upper extent – throughout the video. The unique viewing perspective from the ISS cupola allows for a sense of the 3-dimensional nature of the phenomena as it varies in apparent length, width, and thickness as the ISS orbits above it," says NASA.
The North and South Poles light up at night with auroras because a "solar wind" of electrified gas continually flows outward from the sun.
The Earth's magnetic field provides an obstacle in the flow of the solar wind. However, under certain conditions charged particles from the solar wind are able to get through Earth's magnetic shield and get energized, say NASA scientists.
"When ions in the solar wind collide with atoms of oxygen and nitrogen in the upper atmosphere, atoms excited by these collisions emit light as they return to their original energy level, creating the visible aurora. The most commonly observed color of aurora is green, caused by light emitted by excited oxygen atoms," according to Melissa Dawson and William Stefanov at NASA's Johnson Space Center.
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.
