Crescent Saturn


On Earth we never see Saturn in a crescent phase because it is farther from the Sun than Earth, and it is always fully illuminated from our point of view. The Cassini spacecraft’s orbits around the planet allowed its cameras to see Saturn in ways not possible from Earth.

Image Credit: NASA

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

Moar Science from Cassini


As the Cassini spacecraft was running out of fuel for the thrusters used to maintain control of its attitude so that it could point it instruments at the desired targets and its antenna toward Earth so send back data, it was placed in a series of Grand Finale orbits that took it between Saturn’s rings and the planet’s upper atmosphere. Eventually, an orbit was low enough that the spacecraft burned up in the upper atmosphere. It will take years to go through all the data, but papers are beginning to be published with findings from the Grand Finale. Interesting findings include an electric current that flows between the rings and the upper atmosphere and organic compounds falling as “rain” from the rings. There’s more interesting stuff here. Go take a look.

Image Credit: NASA

Not a Solar Eclipse


titanbusy_cassini_960No, it’s not a solar eclipse. It’s a picture of the rings and a couple of the moons of Saturn. The large object near the center is Titan, Saturn’s largest moon and one of the most interesting objects in the entire Solar System. The central dark spot is the body of the moon. The bright halo is atmospheric haze above Titan. The gases of the atmosphere scatter sunlight. Saturn’s rings are shown nearly edge on. Enceladus, a small moon, is at about 4 or 5 o’clock at the edge of Titan.

This image was taken with the Cassini spacecraft’s camera pointing almost directly at the Sun, so the surfaces of Titan and Enceladus appear in silhouette, and the rings of Saturn look like a photographic negative.

Image Credit: NASA

You Can’t See This From Here


Crescent SaturnThis is a view of Saturn partially lit in crescent phase, a view that can only be seen when the object is between the observer and the Sun. From the Earth, we can only see Mercury and Venus in varying crescent phases and Mars and the other outer planets fully lit. Because the Moon can be either between the Earth and the Sun or farther away, we see it go through all the phases from New to Full to New again.

This picture of Saturn was made by the Cassini spacecraft.

Image Credit: NASA

Tuning in on Saturn


New research from the up-close Grand Finale orbits of the Cassini mission shows a surprisingly powerful interaction of plasma waves moving from Saturn to its moon Enceladus. The data used to make this video was captured by the Radio Plasma Wave Science (RPWS) instrument two weeks before Cassini was deliberately plunged into the atmosphere of Saturn.

Video Credit: NASA / JPL-Caltech / University of Iowa

Odysseus


Don’t worry. It’s a moon, not a space station.

It’s Saturn’s icy moon Tethys. The enormous impact created the crater is named Odysseus. The crater is about 450 km across surrounded by a ring of steep cliffs and and has a rang of mountains rising from its center. Tethys is only a bit over 1070 km in diameter.

This picture is a composite assembled from images taken in visible light with the Cassini spacecraft in 2015 when is was roughly 44,500 km from the moon.

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

Enceladus, Pandora, and Rings (Oh, My!)


Saturn’s moon Enceladus is backlit by the Sun in this Cassini spacecraft image from 2009. The dramatic lighting shows of the plumes that continuously spew into space from the south pole of 500 km diameter moon. The icy plumes are likely fed by an ocean beneath the ice shell of Enceladus. They supply material directly to Saturn’s outer, tenuous E ring and make the surface of Enceladus as reflective as snow. Behind Enceladus, Saturn’s rings scatter sunlight toward Cassini. Beyond the rings, the night side of the 80 km diameter moon Pandora is faintly lit by light reflecting off of Saturn.

Image Credit: NASA