Jupiter and two of the Galilean Moons appear in a telephoto view over the Grand Canyon in northern Arizona. To its right is bright red-orange star Aldebaran in the Bull's head, the prominent V-shaped part of the constellation Taurus. On the ground is the longest canyon on the Earth, a steep-sided gorge carved by the Colorado River steadily in about 17 million year time span. The canyon is 446 km long, ranges in width from about 6 to 29 km and attains a depth of more than 1.6 km or about a mile.