On May 19, 2005, Mars Exploration Rover Spirit captured this stunning view as the sun sank below the rim of the Gusev crater on Mars. This image mosaic was taken around 6:07 on the evening of the rover's 489 Martian day, or sol. Because Mars is farther from the Sun than the Earth is, the Sun appears only about two-thirds the size that it appears in a sunset seen from the Earth.