Saturn and Some of Its Moons


The animation shows the orbits of Saturn’s visible moons Tethys, Janus, Mimas, Enceladus, and Rhea over the observing run in June, 2019 (with elapsed time bar).

Video Credits: NASA / ESA / A. Simon (Goddard Space Flight Center) / M.H. Wong (University of California, Berkeley) / J. DePasquale (STScI)

Herschel Crater


Herschel Crater is 130 km wide, covering a large portion of Saturn’s moon Mimas. The moon itself is only 396 km wide.

The dayside terrain seen here is on leading hemisphere of Mimas. North on Mimas is up and rotated 1 degree to the left in this image which was taken in visible light by the Cassini spacecraft in 2010.

Image Credit: NASA

Saturn, Rings, and Moons


Cassini snapped this picture with its narrow-angle camera. It shows Saturn and its rings seen here nearly edge on. The image also shows the moons Mimas (above the rings), tiny Janus (apparently almost in the rings), and Tethys (below the rings). “Above” and “below” the rings is a matter of perspective. All three moons and the rings orbit Saturn in roughly the same plane.

Image Credit: NASA

Shadow on the Rings


ring shadows 2The changing length of Saturn’s shadow marks the passing of the planet’s seasons. As the planet nears its northern-hemisphere solstice in May, 2017, the shadow will get even shorter. At solstice, the shadow’s edge will be about 45,000 km from the planet’s surface, barely making it past the middle of the B ring.

The white speck in the lower left of the picture isn’t a dust mote on your monitor. It’s the moon Mimas, only a few pixels wide in this image.

Image Credit: NASA

A Great Divide


A Great DivideThe rings of Saturn are very thin, but they are very, very wide; the Cassini Division (seen here between the bright B ring and dimmer A ring) is almost as wide as the planet Mercury. The 4,800-km-wide division in Saturn’s rings is probably caused by the moon Mimas. Particles within the division orbit Saturn almost exactly twice for every time Mimas orbits. That results in a series of gravitational nudges from the moon which sculpt the outer edge of the B ring and keep its particles from drifting into the Cassini Division.

Image Credit: NASA