Deimos, Phobos and the Moon (IMAGE) Southwest Research Institute Caption This composite image compares how big the moons of Mars appear, as seen from the surface of the Red Planet, in relation to the size that our Moon appears from Earth's surface. While Earth's Moon is 100 times bigger than the larger Martian moon Phobos, the Martian moons orbit much closer to their planet, making them appear relatively larger in the sky. Deimos, at far left, and Phobos, beside it, are shown together as photographed by NASA's Mars rover Curiosity on Aug. 1, 2013. Credit NASA/JPL-Caltech/Malin Space Science Systems/Texas A&M 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.