The evidence for an “ocean” of water under the surface of Saturn’s moon Enceladus appears to be overwhelming.
The little world has excited scientists ever since jets of icy material were seen squirting into space from a striped region at its south pole.
Now, exquisite measurements using Nasa’s Cassini probe as it flew over the moon have allowed researchers to detect the water’s gravitational signal.
Science magazine reports the details.
“The measurements that we have done are consistent with the existence of a large water reservoir about the size (volume) of Lake Superior in North America,” Prof Luciano Iess told BBC News.
A European comparison would be 245 times the water mass of Lake Garda in Italy.
The findings of Prof Iess and his team will boost the view that the 500km-wide moon would be one of the best places beyond Earth to go look for the existence of microbial life.
Cassini’s data suggests the liquid volume lies about 40km under Enceladus’s ice crust.
This would put it directly on top of the moon’s layered, rocky interior.
The case for a subglacial ocean has been growing ever since Cassini first sensed a diffuse atmosphere at the moon in 2005.
Subsequent observations pinned the source of this atmosphere to mineral-rich streams of water vapour flowing away from surface fractures dubbed “tiger stripes” for their resemblance to the markings on a big cat.
