It has been a season of sky pageants. March 24 and 25 saw a lunar eclipse across the Americas, Europe, and North and East Asia. April 8 featured the total solar eclipse in North America. March and April also brought the appearance of the evocatively named Devil Comet. And last weekend, earthlings were treated to a spectacular light show when a geomagnetic explosion on the sun, known as a coronal mass ejection, produced a colorful display of the aurora borealis, a phenomenon usually limited to the north polar region...