Figure 11-43: R I V U X G
The Moons of Mars (a) The Spirit rover recorded seven images of the Martian night sky at 15-minute intervals to produce this composite view of the motions of Deimos and Phobos. (b) Two Mars Reconnaissance Orbiter images have been combined to show Deimos and Phobos and their heavily cratered surfaces to the same scale. The gravity on these moons is only about 1/1000 of Earth’s, and not strong enough to shape them into spheres.
The Moons of Mars (a) The Spirit rover recorded seven images of the Martian night sky at 15-minute intervals to produce this composite view of the motions of Deimos and Phobos. (b) Two Mars Reconnaissance Orbiter images have been combined to show Deimos and Phobos and their heavily cratered surfaces to the same scale. The gravity on these moons is only about 1/1000 of Earth’s, and not strong enough to shape them into spheres.
(a: NASA/JPL/Cornell/Texas A&M; b: NASA/JPL Caltech/University of Arizona)