Craters (IMAGE) Osaka University Caption The density of 0.1-1 km-diameter craters (green) in ejecta of the Copernicus crater was examined to derive chronological information (Terrain Camera image) Credit Osaka University Usage Restrictions None 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.