Washington: New gravity data from the Cassini spacecraft showed that Enceladus, one of Saturn’s smaller moons, harbours a large, possibly regional subsurface ocean with a rocky seafloor.
The study, published Thursday in the US journal Science, indicated that a roughly 10-km-thick layer of liquid water lies beneath 30 to 40 km of crustal ice at the south pole of the 500-km-diameter Enceladus, Xinhua reported.
Italian and American researchers investigated the moon’s gravity field and the notable asymmetry it exhibits between northern and southern hemispheres to reach these conclusions.
“Using geophysical measurements, we have been able to confirm that there is a large ocean beneath the surface of Enceladus’ south-polar region,” said co-author David Stevenson, professor of planetary science at the California Institute of Technology.
“This provides a possible source for the water that Cassini has seen spewing from the geysers in this region,” Stevenson said.
The researchers analysed the so-called Doppler Effect data from three of Cassini’s flybys between 2010 and 2012, which brought the spacecraft within 100 km of Enceladus’ surface.
They found that the southern polar region of the moon doesn’t have enough mass at its surface to account for the hemisphere’s gravity field, suggesting that something dense below the surface of Enceladus, probably liquid water, must be compensating.