Date Acquired: September 29, 2009
MESSENGER imaged Mercury’s partially sunlit surface on its approach to the planet yesterday. This WAC image reveals approximately an additional 5% of the surface (outlined in red) that had been previously unseen by spacecraft. Among the many newly imaged surface features are impact craters, smooth plains, and an intriguing double-ring basin approximately 260 kilometers (125 miles) in diameter. Rembrandt basin straddles Mercury’s terminator (along the right side of the image).
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington