Astronomy Picture of the Day

Explanation: What bizarre alien planet is this ? It's planet Earth of course, seen through the shimmering glow of aurorae from the International Space Station. About 400 kilometres (250 miles) above, the orbiting station is itself within the upper realm of the auroral displays, also watched from the planet's surface on June 23rd. Aurorae have the signature colours of excited molecules and atoms at the low densities found at extreme altitudes. The eerie greenish glow of molecular oxygen dominates this view. But higher, just above the space station's horizon, is a rarer red band of aurora from atomic oxygen. The ongoing geomagnetic storm began after a coronal mass ejection's recent impact on Earth's magnetosphere.