Cassini Spacecraft Crosses Saturn's Ring Plane
If this is Saturn, where are the rings? When Saturn's "appendages" disappeared in 1612,
Galileo did not understand why. Later that century, it became understood that Saturn's
unusual protrusions were rings and that when the Earth crosses the ring plane, the edge-on
rings will appear to disappear. This is because Saturn's rings are confined to a plane many
times thinner, in proportion, than a razor blade. In modern times, the robot Cassini spacecraft
orbiting Saturn now also crosses Saturn's ring plane. A series of plane crossing images from
late February was dug out of the vast online Cassini raw image archive by interested Spanish
amateur Fernando Garcia Navarro. Pictured above, digitally cropped and set in representative
colors, is the striking result. Saturn's thin ring plane appears in blue, bands and clouds in
Saturn's upper atmosphere appear in gold, and dark shadows of the rings curve across the top
of the gas giant planet. Moons appear as bumps in the rings.