Postcard From Cassini

PIA17157 detail
There is always this. Given the times, and the scale of science fiction, perhaps the idea of a holiday snap featuring four moons does not necessarily strike us as anything special. But then we stop to think about it:

Two pairs of moons make a rare joint appearance. The F ring’s shepherd moons, Prometheus and Pandora, appear just inside and outside of the F ring (the thin faint ring furthest from Saturn). Meanwhile, farther from Saturn the co-orbital moons Janus (near the bottom) and Epimetheus (about a third of the way down from the top) also are captured.

Prometheus (53 miles, or 86 kilometers across) and Pandora (50 miles, or 81 kilometers across) sculpt the F ring through their gravitational influences. Janus (111 miles, or 179 kilometers across) and Epimetheus (70 miles, or 113 kilometers across) are famous for their orbital dance, swapping places about every four years. They are also responsible for gravitationally shaping the outer edge of the A ring into seven scallops.

NASA/JPL-Caltech/SSI)

Just to go clockwise, that’s Epimetheus, Prometheus, Pandora, and Janus.

Seriously, though … anyone have a holiday snap to match? Didn’t think so.