Planet Mercury (IMAGE) University of Arizona Caption A new view of Mercury obtained during a flyby on Jan. 14, 2008. This mosaic from three different images shows Caloris, the solar system's largest basin -- a huge, ancient crater filled in with volcanic material -- in the upper right. Credit NASA/JHUAPL/CIW Usage Restrictions Usage only permitted in conjunction with reporting/posting of this news release. Image credit must be included. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.