A Cosmic Dartboard (IMAGE) Brown University Caption Experiments using a high velocity cannon suggest that when asteroids hit targets that are icy or made of porous silicate materials, much of the impact material stays in the crater. The findings have implications for the surface composition of the dwarf planet Ceres. Credit NASA Ames Research Center / Brown 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.