Orbiting the Saturnian system since 2004, NASA's Cassini mission has enriched us incredible views of the seemingly flat ring plane. Beyond the robotic probe's camera resolution, however, are the ripples and waves that are inevitably caused by the gravities of small moons embedded in the many ring gaps. In one 26-mile-wide gap, called the Keeler Gap, a 5-mile-wide moon roams and it has a pretty dramatic effect on the tiny particles at the gap's borders.
The oblique viewing angle is a little misleading; we're not looking directly down on the ring plane, we're actually looking at the moon from the side. The waves in the foreground are therefore rippling up and down as the moon goes about its orbit. The ring gap also looks more narrow than its 26-mile width, an optical effect known as foreshortening. Cassini was 17,000 miles from the moon when this image was captured on Jan. 16.
Previously, in 2009, Cassini was able to spot these waves in Saturn's rings, albeit from afar, when the ringed gas giant was passing through its equinox. At this time, the ring plane was parallel to the direction of sunlight, allowing any vertical structures in the rings to cast a long shadow:
|Cassini's view of Daphnis and the waves it creates in 2009 when the spacecraft was 414,000 miles from the moon|
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