A Flying Leap (IMAGE) Brown University Caption Researchers used computer models to simulate the path of ejecta from Stickney crater on Mars' moon Phobos. The simulations show how boulders take a flying leap over one particular area of Phobos, explaining why it's devoid of grooves. Credit Ken Ramsley / 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.