Thanks to Cassini we’ve known about the jets of icy brine spraying from the south pole of Saturn’s moon Enceladus for about 8 years now, but this week it was revealed at the 44th Lunar and Planetary Science Conference outside Houston, Texas that Enceladus’ jets very likely reach all the way down to the sea — a salty subsurface sea of liquid water that’s thought to lie beneath nearly 10 kilometers of ice.
“To touch the jets of Enceladus is to touch the most accessible salty, organic-rich, extraterrestrial body of water and, hence, habitable zone, in our solar system.”
– Cassini imaging team leader Carolyn Porco
Enceladus, Saturn’s 318-mile-wide moon that’s become famous for its ice-spraying southern jets, is on astronomers’ short list of places in our own solar system where extraterrestrial life could be hiding — and on March 27, NASA’s Cassini spacecraft was in just the right place to try and sniff it out.
Why does Cassini team director Carolyn Porco think Enceladus is THE place in the solar system where we are most likely to find life? Find out here.
Little Enceladus and enormous Titan are seen on either side of Saturn’s rings in this image, a color-composite I made from raw images acquired by Cassini on March 12, 2012.
On Saturday, Oct. 1, the Cassini spacecraft performed another flyby of Saturn’s moon Enceladus. Passing by at a distance of only 62 miles (99 km) Cassini took some fantastic images of the 318-mile-wide moon — most notably of its signature plumes of water ice spraying from fissures along its south pole!
Researchers on the Cassini mission team have identified large salt grains in the plumes emanating from Saturn’s icy satellite Enceladus, making an even stronger case for the existence of a salty liquid ocean beneath the moon’s frozen surface.
Scientists have uncovered a shocking surprise about Saturn’s ice-spewing satellite Enceladus: the little 318-mile-wide moon creates a loop of electrically-charged particles that run from its north and south poles all the way up and over to Saturn’s north and south poles, forming a giant electron beam connecting the gas planet and its icy moon. Where the electron particles connect with Saturn’s northern atmosphere astronomers have identified an ultraviolet “footprint”, about the size of the state of California. (A corresponding footprint near Saturn’s south pole has not yet been identified.)
Using Cassini data from 2008 this planet-moon connection has just recently been confirmed and published in the journals Nature and Geophysical Research Letters.
Cassini gets a nice look at Enceladus’ icy, cratered north pole in this image, taken on December 21, 2010. In the background we catch a glimpse of Saturn’s rings as well! Fantastic image.
The Cassini spacecraft was about 20,000 miles (34000 km) from Enceladus when this was taken, using its narrow-angle camera.
318 miles across at its widest point, Enceladus’ wrinkled surface is composed mostly of water ice that has been cracked, stretched and folded into ridges due to tectonic activity that may be the result of a liquid water interior. Without a doubt the water is there – it’s being actively sprayed out into space through fissures in the moon’s south pole! – but the volume and heat source of that liquid water still remains to be discovered.
Being covered in ice makes Enceladus is extremely bright; it reflects nearly 100% of the sunlight that hits it. This also keeps the moon very cold…the surface temperature on Enceladus is minus 330º F! Still, some process is keeping parts of the moon warm enough for liquid water to exist, and this is what scientists on the Cassini team are still trying to learn more about.
In fact, recent discoveries have found that the southern region of Enceladus – where the jets are – is generating much more heat and energy than previously expected…well over twice the amount put out by all of the geysers in Yellowstone National Park! This is quite a surprising find on an icy little moon out in the frigid region of space around Saturn. And, of course, where we find liquid water and heat we may also find the possibility of life…and this is exactly why scientists are now so intrigued by Enceladus!
“The possibility of liquid water, a tidal energy source and the observation of organic (carbon-rich) chemicals in the plume of Enceladus make the satellite a site of strong astrobiological interest.”
– Carly Howett, Southwest Research Institute, Boulder, CO
Image: NASA / JPL / SSI