An ocean on Saturn's largest moon, Titan, could be even saltier than the Dead Sea.
The study results come from gravity and topography collected by flybys performed by NASA's Cassini spacecraft, NASA reported. The data gave the researchers new insight into the structure of the moon's outer ice shell.
The findings are published in this week's edition of the journal Icarus.
"Titan continues to prove itself as an endlessly fascinating world, and with our long-lived Cassini spacecraft, we're unlocking new mysteries as fast as we solve old ones," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory (JPL) inPasadena, California, who was not involved in the study.
The findings suggest the moon's ice shell is currently in the process of freezing solid. In order to explain the gravity data the researchers determined the water had a relatively high density, suggesting the ocean is extremely salty and rich in sulfur, sodium and potassium. This composition is about equivalent to Earth's dead sea.
"This is an extremely salty ocean by Earth standards," said the paper's lead author, Giuseppe Mitri of the University of Nantes inFrance. "Knowing this may change the way we view this ocean as a possible abode for present-day life, but conditions might have been very different there in the past."
Cassini data also revealed the thickness of Titan's shell varies In different regions, as if the ocean was crystallizing and icing over. If this was not occurring the moon would be able to even itself out over time.
The rigid ice shell is also outgassing methane into Titan's atmosphere creating "hot spots." The moon's atmosphere has about five percent methane, meaning it must come from somewhere, but researchers are unsure of the source.
"Our work suggests looking for signs of methane outgassing will be difficult with Cassini, and may require a future mission that can find localized methane sources," said Jonathan Lunine, a scientist on the Cassini mission at Cornell University, Ithaca, New York, and one of the paper's co-authors. "As on Mars, this is a challenging task."
