When NASA's Messenger space probe swung past Mercury on September 29, it snapped this picture of the innermost planet's barren and strange landscape.
The $446 million probe's third flyby brought it within 142 miles (228 km) of Mercury's surface to cover more uncharted terrain, leaving 98 percent of the planet now mapped [SPACE.com].
The images taken and the data recorded during the flyby are the last that will be acquired until Messenger finally slips into orbit around Mercury in 2011. The probe has now completed about three-quarters of its swooping 4.9-billion-mile journey that will eventually bring it into orbit. Researcher Brett Denevi explains that this enhanced color shot shows
a bright area surrounding an irregular depression, with steep sides and an odd shape, "all of which are hallmarks of something like a volcanic vent," Denevi said [SPACE.com].
The double-ring basin in the center of the photo measures about 180 miles in diameter. It appears to be a relatively young impact crater--researchers believe it formed about 1 billion years ago--and the smooth stuff on the crater floor may be even younger volcanic material. Related Content: 80beats: Space Probe Soon to Study Mercury’s Comet-Like “Tail” 80beats: Mercury Flyby Reveals Magnetic Twisters and Ancient Magma Oceans 80beats: Brand New Postcards From Mercury, Courtesy of Messenger Space ProbeImage: NASA