Saturn with moons Dione and Enceladus, courtesy of a Cassini fly-by
Perhaps what makes this image so interesting, though, is the background. First, the large orb looming behind Dione is Saturn itself, faintly lit by sunlight first reflected from the rings.
Next, the thin lines running diagonally across the image are the rings of Saturn themselves. The millions of icy rocks that compose Saturn’s spectacular rings all orbit Saturn in the same plane, and so appear surprisingly thin when seen nearly edge-on. … A careful inspection of the ring plane [shows] the moon Enceladus on the upper right.
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