Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. Pictured above is the closest of Jupiter's Galilean Satellites , Io , superposed in front of the giant planet it circles. To the left of Io is a dark spot that is its own shadow. The tremendous complexities that can be seen in Jupiter's banded, swirling atmosphere are being studied and may provide insight as to how Earth's atmosphere behaves. Engineers continue to study the Cassini spacecraft itself to understand why it required more force than normal to turn one of its maneuvering wheels.
Specific rights apply .