Saturn's Moons as seen by Cassini

[Rick]

Saturn's moon Tethys 'once had ocean'

One of Saturn's moons may once have harboured a liquid ocean beneath its icy surface, scientists have told a major conference in Houston, Texas.

Tethys is a mid-sized satellite with a density close to that of pure ice.

But a large valley system visible today must have formed when the crust was being heated and under great strain.

The team thinks that tidal heating, followed by cooling which froze Tethys' ocean, could have formed the giant Ithaca Chasma rift.

More: http://news.bbc.co.uk/2/hi/science/nature/7297408.stm

[Rick]

NASA's Cassini spacecraft has survived an "in your face" flyby of Saturnian moon Enceladus designed to collect data on geysers spewing water vapour and other matter from giant fractures at the body's south pole.

Cassini on Wednesday skirted the geysers' plumes at a tad over 51,000km/h (32,000mph) at a height of 200km (120 miles), passing just 50km (30 miles) above Enceladus's surface at closest approach.

During the "sniff and taste" of the plume, the craft deployed its Cosmic Dust Analyzer and Ion and Neutral Mass Spectrometer, although all did not go exactly according to plan.

More: http://www.theregister.co.uk/2008/03/14/cassini_enceladus/

[mickw]

A sniff test of water vapor spewing from Saturn's moon Enceladus shows it is gushing with organic molecules, increasing the possibility of life existing somewhere in the Saturn system.
Scientists have been intrigued by the moon since the fountain of water was first spotted in 2005. Now they've identified a soup of prebiotic material there, similar to what's found in comets, from an analysis of data collected by the Cassini spacecraft.

More:  http://www.space.com/scienceastronomy/080326-cassini-flyby-update.html

[Rick]

NASA's Cassini spacecraft has sampled a "surprising organic brew" erupting from Saturnian moon Enceladus's south polar region comprising "volatile gases, water vapour, carbon dioxide and carbon monoxide, as well as organic materials".

Cassini performed an "in your face" flypast of the Moon on 12 March, skimming at over 51,000km/h (32,000mph) to within 50km (30 miles) of the surface. During the encounter, it skirted the "geysers" spewing what scientists suspected was water vapour and other material at an altitude of 200km (120 miles) for a quick "sniff and taste" of their composition.

More: http://www.theregister.co.uk/2008/03/27/enceladus_geysers/

[mickw]

The tide may be changing for the ocean suspected under the icy shell of Enceladus. Recent research has shown that this small moon of Saturn does not produce enough heat in its present configuration to keep water from freezing down to its core.

"There is no possible combination of parameters that allow for a thermally stable ocean," said James Roberts of the University of California, Santa Cruz.

Roberts and his colleague Francis Nimmo, also from UCSC, calculated the tidal heating expected inside Enceladus from the uneven tugging of nearby Saturn.

More:   http://www.space.com/scienceastronomy/080619-am-enceladus-ocean.html

[Ian]

http://news.bbc.co.uk/1/hi/sci/tech/7559517.stm

The Cassini spacecraft has returned some remarkable new close-up images of the Saturnian moon Enceladus...

[Rick]

Nasa's Cassini spacecraft has obtained strong evidence that Saturn's tiny moon Enceladus retains liquid water.

The probe has detected sodium salts in the vicinity of the satellite, which appear to spew from its south pole.

Liquid water that is in prolonged contact with rock will leach out sodium - in exactly the same way as Earth's oceans have become salty over time.

More: http://news.bbc.co.uk/1/hi/sci/tech/8115148.stm

[Rick]

Massive geysers on Saturn's moon Enceladus may be fed by a salty ocean beneath the surface, adding weight to speculation it harbors the essential building blocks needed for life.

Scientists working on NASA's Cassini mission have detected sodium salts in ice grains of Saturn's outermost ring. The planet's outer ring, or "E-ring," is believed to be primarily supplied by giant geysers on Enceladus's south polar region tossing out materials to a distance of three times the moon's radius. Cassini's cosmic dust analyzer has examined the composition of the material and found salt within it.

More: http://www.theregister.co.uk/2009/06/25/cassini_enceladus_salt_detected/

[mickw]

Striking new photos of water-vapor geysers erupting from Saturn's moon Enceladus were beamed to Earth this week by NASA's Cassini spacecraft in orbit around the ringed planet.

Cassini made its deepest dive yet into the plumes pouring out from the moon's south pole on Nov. 2 during a planned flyby of Enceladus. The spacecraft approached within about 62 miles (100 km) of the moon's surface.

The powerful plumes, which contain water vapor, sodium and organic chemicals such as carbon dioxide, look a bit like the Old Faithful geyser in Yellowstone National Park. They have intrigued scientists because they suggest that a store of liquid water may be present beneath the moon's crust to give rise to the water vapor in the plumes. And if there is liquid water, there might be the possibility of some kind of alien life.

More:   http://www.space.com/scienceastronomy/091104-enceladus-plumes.html

[Ian]

nice to see the astronomy press have the usual standard of journalistic skill.

Carbon dioxide is not an organic chemical... 

[Rick]

Nasa has released the latest raw images of Saturn's moon Enceladus, from the Cassini spacecraft's extended mission to the planet and its satellites.

The images show the moon's rippling terrain in remarkable clarity.

Cassini started transmitting uncalibrated temperature data and images during a flyby on 21 November.

More: http://news.bbc.co.uk/1/hi/sci/tech/8374194.stm

APOD: http://antwrp.gsfc.nasa.gov/apod/ap091124.html

CICLOPS: http://ciclops.org/view_event/120/Enceladus_Rev_121_Flyby_Raw_Preview

[Mike]

Planetary scientist Carolyn Porco, leader of the Imaging Team on the Cassini mission to Saturn, shows images from the Cassini voyage to Saturn, focusing on its largest moon, Titan, and on frozen Enceladus, which seems to shoot jets of ice.



http://www.ted.com/talks/carolyn_porco_flies_us_to_saturn.html

[Tony G]

Great talk.

But I must say that last image looks awfully like Fay's one that she submitted to UKAI the other day. 

Tony G

[Rick]

There seems little doubt that Saturn's moon Enceladus hides a large body of liquid water beneath its icy skin.

The Cassini probe, which periodically sweeps past the little moon, has returned yet more data to back up the idea of a sub-surface sea.

This time, it is the detection of negatively charged water molecules in the atmosphere of Enceladus.

On Earth, such ions are often seen where liquid water is in motion, such as waterfalls or crashing ocean waves.

More: http://news.bbc.co.uk/1/hi/sci/tech/8495663.stm

[mickw]

Like sprinklers hidden beneath the surface, a series of geysers — more than previously thought — are gushing water ice from fissures near the south pole of Saturn's icy moon Enceladus, new images reveal.

The newly released images from NASA's Cassini spacecraft show the geysers of Enceladus in stunning detail. The photos caught a bounty of previously unknown plumes alongside known ones, and show at least one gusher that's lost power since NASA's last look at the moon.

The new images were taken during Cassini's flyby on Nov. 21, 2009, and include the best 3-D look ever obtained of a "tiger stripe" — a fissure that sprays icy particles, water vapor and organic compounds. They also show regions of Enceladus that were not well-mapped in previous flybys, including a southern area with crudely circular tectonic patterns.

More:   Geysers