Rings, Winds, Moons

Deep in the shady sadness of a vale,
Far sunken from the healthy breath of morn,
Far from the fiery noon, and eve's one star,
Sat gray-hair'd Saturn, quiet as a stone,
Still as the silence round about his lair;
~John Keats, Hyperion

Time for another NASA Art Thursday. These photos are primarily from the Cassini spacecraft. NASA explains, "In 2004, Cassini-Huygens reached Saturn and its moons...In some ways, the Cassini spacecraft has senses better than our own. For example, Cassini can 'see' in wavelengths of light and energy that the human eye cannot. The instruments on the spacecraft can 'feel' things about magnetic fields and tiny dust particles that no human hand could detect." (Side-note: Huygens was a probe that landed on Titan; Cassini is still sending back data.)

Some Saturn Wiki-trivia:
* Although prehistoric people realized that Saturn existed, no one knew about Saturn's rings until Galileo saw them through his telescope in in 1610.
* Saturn has at least 150 moons and "moonlets," the largest of which is Titan.
* Saturn's second largest moon, Rhea, may have a ring system of its own.
* Saturn's moon Enceladus has potential for microbial life.
* It takes Saturn about 29½ years to finish one revolution around the Sun.
* The winds on Saturn are the second fastest among the Solar System's planets (Neptune is first).
* Infrared imaging has shown that Saturn's south pole has a warm polar vortex, the only known example of one in the Solar System.

The Cassini program is an international cooperative effort involving NASA, the European Space Agency (ESA) and the Italian space agency, Agenzia Spaziale Italiana (ASI), and others. Thank you to all of these contributors for the photos we are viewing today!

A rough comparison of sizes of Saturn and Earth

An Earth-Titan comparison

The Rite of Spring
This mosaic shows Saturn, its rings, and a few of its moons a day and a half after exact Saturn equinox, when the sun's disk was exactly overhead at the planet's equator.

Neon Saturn
This striking false-color mosaic was created from 25 images taken by Cassini's visual and infrared mapping spectrometer over a period of 13 hours, and captures Saturn in nighttime and daytime conditions.
High-level, fine particles block Saturn's glow more strongly in the south, making Saturn look brighter in the north.

Hyperion, a moon discovered in 1848
Hyperion has a notably reddish tint when viewed in natural color. The red color was toned down in this false-color view, and the other hues were enhanced, in order to make more subtle color variations across Hyperion's surface more apparent.

Ring Shadows
Currently, the rings' shadows shield the mid-northern latitudes from the harshest of the sun's rays. As Saturn travels around the sun in its 29-year orbit, the shadows will narrow and head southward, eventually blanketing the opposite hemisphere.

Saturn's moon Iapetus, near-true color view

Sizeable Swirls
Huge clouds swirl through the southern latitudes of Saturn.

Secretive Rings
Saturn's rings cut across their own shadows on the planet and hide a tiny secret.
Barely visible in the Encke Gap is the embedded moon Pan (16 miles across). The Encke Gap is the thin, dark line near the rings' outer edge; Pan is a faint speck halfway between center and right.

Links:
Saturn info for kids from NASA
Saturn poetry lesson plan