Volcano Tungurahua in Ecuador erupts about every 90 years—it's a schedule the mountain has kept for 1300 years. This photo was taken by Patrick Taschler in 2006. (Via Astronomy Photo of the Day and Alexandra Witze)
Maggie Koerth-Baker is the science editor at BoingBoing.net. She writes a monthly column for The New York Times Magazine and is the author of Before the Lights Go Out, a book about electricity, infrastructure, and the future of energy. You can find Maggie on Twitter and Facebook.