A dramatic appearance of the phenomenon known as “spokes,” seen here as the dark smudges in the middle of the rings that radiate outward.

Catastrophic water floods carved the canyons of Athabasca Valles, a geologically young system of outflow channels on Mars.

Spirit and Opportunity will mark their fifth Earth year on Mars next month. See more

Titan’s thick, hazy atmosphere renders it as smooth as a tree ornament, just before the giant moon slips behind Saturn’s limb.

A storm blows out of the maze of canyons called Noctis Labyrinthus, the “labyrinth of the night.”