Ithaca Chasma is an ancient and gigantic rift cutting across the heavily cratered surface of Tethys. Less surprising than many of the other moons of Saturn, Tethys does have its own mysteries, including bright crater floors, younger plains, and evidence of very early activity that resulted in Ithaca Chasma.
The Cassini spacecraft orbiting Saturn has returned first images of many of the planet’s moons. This first orbit will be Cassini’s longest, as Saturn and its moons are used to shrink the orbit down to something more science activity-friendly. In 89 days the spacecraft will make a close flyby of Titan.
On its way out, Cassini took the closest images of Titan ever captured. While visual light images depicted the same smog-covered moon, other frequencies of light were used to take images of the surface. Mysteries abound. The predicted lakes or seas of methane were not seen. Instead, the images revealed a diverse surface possibly modified by different geological processes as well as bright methane clouds hovering near the south pole. When Cassini comes around for another pass it will be much closer, allowing much clearer images.
The images of the other moons reveal little more than Voyager images from the 1980s. Future orbits of Cassini will target specific moons, giving each its own moment in the spotlight.
