Saturn’s Rings and Enceladus

Saturn’s most distinctive feature is the thousands of rings that orbit the planet. Despite the fact that the rings look like continuous hoops of matter encircling the giant planet, each ring is actually made of tiny individual particles. Saturn’s rings consist largely of water ice mixed with smaller amounts of dust and rocky matter. Data from the Cassini spacecraft indicate that the environment around the rings is like an atmosphere, composed principally of molecular oxygen.

The ring system is divided into 5 major components: the G, F, A, B, and C rings, listed from outside to inside (but in reality, these major divisions are subdivided into thousands of individual ringlets). The F and G rings are thin and difficult to see, while the A, B, and C rings are broad and easily visible. The large gap between the A ring and and the B ring is called the Cassini division. One of Saturn’s moons, namely; Enceladus is the source of Saturn’s E-ring. The moon’s geyser-like jets create a gigantic halo of ice, dust, and gas that helps feed Saturn’s E ring.

Enceladus has a profound effect on Saturn and its environment. It’s the only moon in our solar system known to substantially influence the chemical composition of its parent planet. The whole magnetic environment of Saturn is weighed down by the material spewing from Enceladus, which becomes plasma – a gas of electrically charged particles.  This plasma, which creates a donut-shaped cloud around Saturn, is then snatched by Saturn’s A-ring, which acts like a giant sponge where the plasma is absorbed. 

Credit: Bjorn Jonsson, NASA/JPL/SSI

Moons and some rings of Saturn, photographed by Cassini, 1 June 2004.  Enceladus is the largest moon seen here (the four diffraction spikes from the narrow-angle camera are unusually clear).  Prometheus sneaks into a couple of frames at the end, just inside the F Ring.  Outside the F Ring are the co-orbital moons Janus and Epimetheus, and I’ve chosen the end-point of the gif so that one loops almost seamlessly into the other.


Animations of Saturn’s aurorae

Earth isn’t the only planet in the solar system with spectacular light shows. Both Jupiter and Saturn have magnetic fields much stronger than Earth’s. Auroras also have been observed on the surfaces of Venus, Mars and even on moons (e.g. Io, Europa, and Ganymede). The auroras on Saturn are created when solar wind particles are channeled into the planet’s magnetic field toward its poles, where they interact with electrically charged gas (plasma) in the upper atmosphere and emit light. Aurora features on Saturn can also be caused by electromagnetic waves generated when its moons move through the plasma that fills the planet’s magnetosphere.  The main source is the small moon Enceladus, which ejects water vapor from the geysers on its south pole, a portion of which is ionized. The interaction between Saturn’s magnetosphere and the solar wind generates bright oval aurorae around the planet’s poles observed in visible, infrared and ultraviolet light. The aurorae of Saturn are highly variable. Their location and brightness strongly depends on the Solar wind pressure: the aurorae become brighter and move closer to the poles when the Solar wind pressure increases.

Credit: ESA/Hubble (M. Kornmesser & L. Calçada)


Cassini Flyby Shows Enceladus Venting
What’s happening on the surface of Saturn’s moon Enceladus? Enormous ice jets are erupting. Giant plumes of ice have been photographed in dramatic fashion by the robotic Cassini spacecraft during this flyby of Saturn’s moon Enceladus. Pictured above, numerous plumes are seen rising from long tiger-stripe canyons across Enceladus’ craggy surface. Several ice jets are even visible in the shadowed region of crescent Enceladus as they reach high enough to scatter sunlight. Other plumes, near the top of the above image, appear visible just over the moon’s sunlit edge. That Enceladus vents fountains of ice was first discovered on Cassini images in 2005, and has been under close study ever since. Continued study of the ice plumes may yield further clues as to whether underground oceans, candidates for containing life, exist on this distant ice world.

Credit: NASA/JPL/SSI; Mosaic: Emily Lakdawalla

Fountains of Saturn’s moon Enceladus backlit by the sun showing the fountain-like sources of the fine spray of material that towers over the south polar region. […] Imaging scientists believe that the jets are geysers erupting from pressurized subsurface reservoirs of liquid water above 273 degrees Kelvin (0 degrees Celsius).

Image Credit: NASA/JPL/Space Science Institute

Source (NASA)

This is a photo of Saturn’s moon Enceladus - a dynamic ice world.  Its surface shifts on geologic timescales, with vast ice sheets spreading and crashing like tectonic plates. Cryovolcanoes (which is a real term that I did not make up) shoot geysers of water out into space.

Recent readings taken by the Cassini spacecraft suggest that Enceladus has a rocky core and liquid oceans beneath the icy surface.

This picture was taken as Cassini was speeding away from Enceladus in 2008, after skimming just 15 miles above its surface.

Happy Saturnalia!


Repeat the sounding joy!

We on the Cassini imaging team deliver to the world this holiday season … what else! … the gift of heavenly imagery starring the majestic globe of Saturn and its two most astounding moons, Titan and Enceladus.

In this, our 10th Christmas offering from across the hundreds of millions of miles that lie between us and Saturn, you will find some of the most splendid and fascinating sights this historic exploration of the ringed planet has uncovered: the hexagonally-shaped jet stream encircling the pole in Saturn’s northern hemisphere, the graceful shadows of its rings arcing across its south, the northern lakes and seas of liquid organics hidden under the hazy atmosphere of Titan, the brilliant ball of glittering ice that is the small active world of Enceladus, and more.

Spend a moment or two and revel in the marvels that our travels in this far-flung planetary system have brought. What wonders we have had for a decade to behold.

Best wishes to all of you, and stay warm, safe, and happy!

CICLOPS: Holiday Offerings All the Way from Saturn