Astronomy Picture of the Day

Explanation: What do aurorae look like from space? From the ground, aurorae dance high above clouds, frequently causing spectacular displays. The International Space Station (ISS) orbits just at the same height as many aurorae, though. Therefore, sometimes it flies over them, but also sometimes it flies right through. The auroral electron and proton streams are too thin to be a danger to the ISS, just as clouds pose little danger to airplanes. ISS Science Officer Don Pettit captured a green aurora, pictured above in a digitally sharpened image. From orbit, Dr. Pettit reports, changing aurorae can appear to crawl around like giant green amoebas. Far below, on planet Earth, the Manicouagan Impact Crater can be seen in northern Canada.