That’s No Space Station. It’s a Moon!


TethysSaturn’s moon Tethys’s trailing side shows two terrains that tell a story of a rough past. To the north (up in this picture) is older, rougher terrain, while to the south is new material dubbed “smooth plains” by scientists. The smooth plains are roughly antipodal to the large impact crater Odysseus. Odysseus, which is on the far side of Tethys, is out of view. The leading theory is that the impact that created Odysseus also created the smooth plains, although exactly how this happened is not yet clear.

Image Credit: NASA

Pan and Zoom


Pan in the gap
Pan_zoomSaturn’s moon Pan, named for the Greek god of shepherds, rules over quite a different domain—the Encke gap in Saturn’s rings. See the inset at left for a zoomed in view. Pan (28 km across) keeps the Encke gap open through its gravitational influence on the ring particles nearby.

This view looks toward the sunlit side of the rings from about 48 degrees above the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Christmas Day, 2013, from a distance of approximately 2.3 million km from Pan. The image scale is about 14 km) per pixel.

Image Credit: NASA

B and C in UV


RingsInUVOn 1 July, 2004, the Cassini spacecraft arrived at Saturn, marking the end of the spacecraft’s nearly seven-year journey through the solar system and the beginning of its tour of Saturn and the planet’s rings and moons.

This picture was taken in ultraviolet on 30 June, 2004 during Cassini’s orbital insertion maneuver. It shows, from left to right, the outer portion of the C ring and inner portion of the B ring which begins a little more than halfway across the image. The “dirty” particles are indicated by red, and “cleaner: ice particles shown in turquoise.

Saturn’s ring system is labeled from the inside out with the D, C, B and A rings followed by the F, G and E rings.

Image Credit: NASA

Rings and Shadows


ring shadowsjpgSaturn’s rings cast shadows on the planet, but the shadows appear to be inside out! The edge of Saturn’s outermost A ring can be seen at the top left corner of this picture taken by the Cassini spacecraft.  Moving down the image, one can see the faint Cassini Division, the opaque B ring, and the innermost C ring. The C ring contains several ringlets which appear dark against Saturn..  The bottom half of the picture shows the shadows of the rings in reverse order on the surface of the planet: the C ring, the B ring, the Cassini Division, and the inner half of the A ring.

Image Credit: NASA