This image provided by NASA Tuesday Oct. 7, 2008 shows the planet Mercury taken on Oct. 6, 2008, at roughly 4:40 a.m. ET, when MESSENGER flew by Mercury for the second time this year. MESSENGER is the first mission sent to orbit the planet closest to thesun. During the encounter, the probe swung just 125 miles (200 kilometers) above the cratered surface of Mercury, snapping hundreds of pictures and collecting a variety of other data from the planet as it gains a critical gravity assist that keeps the probe on track to become the first spacecraft ever to orbit the innermost planet beginning in March 2011. The spectacular image shown here is one of the first to be returned. It shows Mercury about 90 minutes after the spacecraft's closest approach. (AP Photo/NASA)