September 22, 2011
Look at this magnificent video of the aurora australis, captured by cameras mounted on the belly of the International Space Station. These flickering, colored lights in the atmosphere are caused by electrons trapped in Earth’s magnetic field. We call the flickering lights the aurora borealis, or "northern lights" here in the northern hemisphere. But the space station was flying over the south pole when it recorded this video, and when seen over Antarctic regions they are called the aurora australis, or "southern lights." NASA says that it may be the best video ever captured of this ghostly phenomenon.
The sun is never at rest, but the amount of solar activity changes over eleven-year cycles in which the sun is alternately very quiet, and the years it has many storms. We are entering a new, active cycle, and the aurora you see in this video was caused by a geomagnetic storm on the sun that launched a blazing hot coronal mass ejection (CME) toward the earth. No one has a better view of its effect on Earth than the crew of the International Space Station. The lights are so bright that you can see the underside of the space station grow green in the reflected light.
Video: Taken over the southern Indian Ocean, the movie spans a 23-min period from 17:22:27 to 17:45:12 GMT on Sept. 17. Courtesy NASA.
Posted by: Seymour Simon