Corner-Cube Prism (IMAGE) University of California - San Diego Caption Apollo astronauts left arrays of corner-cube prisms, like the one shown here, on the moon 40 years ago. Now light bouncing back from these reflectors appears to have dimmed. Scientist think dust is to blame. Credit UC San Diego 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.