Analysis of Planetary Data Confirms Evidence of an Ocean of Liquid Water Beneath Ice Shell of Saturn’s moon Enceladus

A liquid environment where alien life could exist 

Illustration of the interior of Saturn's moon Enceladus showing a global liquid water ocean between its rocky core and icy crust. Thickness of layers shown here is not to scale. Image credit: NASA/JPL-Caltech
Illustration of the interior of Saturn’s moon Enceladus showing a global liquid water ocean between its rocky core and icy crust. The thickness of layers shown here is not to scale. Image credit: NASA/JPL-Caltech

Space news (September 29, 2015) – 30 miles above the icy surface of Saturn’s moon Enceladus – 

NASA planetary scientists and astrophysicists studying seven years of Cassini images and gravitational data provided by the Cassini Solstice Mission believe they have proof positive of the existence of a global liquid ocean of water beneath the icy shell of Saturn’s moon Enceladus. 

NASA's Cassini spacecraft continues to orbit near Saturn. Astrophysicists expect to make even more discoveries in the future.
NASA’s Cassini spacecraft continues to orbit near Saturn. Astrophysicists expect to make even more discoveries in the future. Image credit: JPL/NASA.

By carefully mapping craters and other surface features planetary scientists were able to precisely measure changes in the rotation of Enceladus, which indicated a slight wobble in its orbit. A slight wobble they believe is caused by Enceladus not being perfectly round and traveling faster and slower at different times and positions of its orbit around Saturn. This difference in velocity as it orbits the sixth planet from Sol, causes Saturn to gently rock the moon as it rotates on its axis, producing the slight wobble. 

Planetary scientists found the only way they can account for the magnitude of the very small wobble called a libration- of Enceladus in computer simulations, is if a global ocean of liquid water exists beneath its outer ice shell.

“This was a hard problem that required years of observations, and calculations involving a diverse collection of disciplines, but we are confident we finally got it right,” said Peter Thomas, a Cassini imaging team member at Cornell University, Ithaca, New York, and lead author of the paper.

This is in line with previous data obtained by Cassini and interpreted by planetary scientists as a fine spray of water vapor containing icy particles and basic organic molecules erupting from surface fractures near Enceladus’s southern pole region. Astrophysicists believe the global ocean their analysis indicates exists beneath the ice shell of Enceladus is the source of the fine spray and a possible habitat life could develop and survive in.

“If the surface and core were rigidly connected, the core would provide so much dead weight the wobble would be far smaller than we observe it to be,” said Matthew Tiscareno, a Cassini participating scientist at the SETI Institute, Mountain View, California, and a co-author of the paper. “This proves that there must be a global layer of liquid separating the surface from the core,” he said.

Planetary scientists are currently trying to figure out where the energy keeping the global ocean from completely freezing is coming from. At this point, they think tidal forces due to the gravity of Saturn could be producing a lot more energy than previously calculated. 

“This is a major step beyond what we understood about this moon before, and it demonstrates the kind of deep-dive discoveries we can make with long-lived orbiter missions to other planets,” said co-author Carolyn Porco, Cassini imaging team lead at Space Science Institute (SSI), Boulder, Colorado, and visiting scholar at the University of California, Berkeley. “Cassini has been exemplary in this regard.”

Where’s the heat coming from?

The heat energy keeping the global ocean of Enceladus from freezing could be partly coming from geothermal sources on the bottom of the ocean. Cassini is scheduled to pass over Enceladus again on October 28, 2015, at which time it will only be about 30 miles (49 kilometers) above the surface of the moon, which is the closest the spacecraft will come to the surface. Planetary scientists want to pass through the icy spray, again, to collect more data, and hopefully, determine the reasons the global ocean isn’t frozen.

You can read and learn more about Cassini’s mission to Saturn here.

Go here to discover NASA’s mission to the stars and their future plans.

You can learn more about Saturn’s moon Enceladus here.

Read about a magnetar NASA scientists believe is orbiting the supermassive black hole at the center of the Milky Way, Sagittarius A.

Learn about NASA’s search for the ‘Crucible of Life’.

Read about the search for the missing link in black hole evolution.

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NASA’s Cassini Orbiter Captures Images of Methane Clouds Moving Over Northern Seas of Saturn’s Moon Titan

NASA's Cassini Orbiter tracks methane clouds moving over Titan's northern seas Ligeia Mare
NASA’s Cassini Orbiter tracks methane clouds moving over Titan’s northern seas Ligeia Mare

Methane clouds over northern seas could signal arrival of summer storms

Space news (the solar system: Saturn; Titan) – looking for evidence of clouds moving over surface of Saturn’s moon Titan –

Planetary space scientists have been looking for evidence of clouds moving over the northern hydrocarbon seas of Saturn’s moon Titan for awhile. Their planetary models of Titan predicted the movement of clouds over the northern seas, which should signal the arrival of summer storms. Near the end of July, they were provided with the proof they require in the form of images of methane clouds moving at 7 to 10 mph across the sky above the hydrocarbon seas of Titan’s northern sea Ligeia Mare. You can watch a movie showing the movement of clouds over the northern seas of Titan here.

NASA's Cassini Orbiter captured images of clouds active over the northern seas of Titan
NASA’s Cassini Orbiter captured images of clouds active over the northern seas of Titan

“We’re eager to find out if the clouds’ appearance signals the beginning of summer weather patterns, or if it is an isolated occurrence,” said Elizabeth Turtle, a Cassini imaging team associate at the Johns Hopkins University Applied Physics Lab in Laurel, Maryland. “Also, how are the clouds related to the seas? Did Cassini just happen to catch them over the seas, or do they form preferentially?”

Work continues for the team

Planetary scientists will continue to watch and study seasonal changes on Saturn’s moon Titan in order to learn more about the weather systems on other worlds and our own. This will be a job requiring patience, because a year on Titan is equivalent to 30 years on Earth, and each season lasts around seven years.

You can find additional information on NASA’s Cassini Solstice Space Mission here.

You can find more information on the Cassini Orbiter Space here.

 

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