The hydrocarbon lakes on Saturn’s largest moon Titan get a lot of press, but a smaller moon known as Enceladus had been of great interest to scientists as well. After today, it very well may become just as famous as its big brother. NASA’s Cassini probe has returned data that shows a vast ocean of liquid water exists beneath Enceladus’ thick ice sheets.
It is believed that the reservoir of water on Enceladus has a volume similar to Lake Superior here on Earth. Enceladus is Saturn’s sixth largest moon at just 310 miles in diameter. So this ocean, which is centered on the south pole, could encompass most or all of the moon. Even if it is restricted to the polar region, it would still be a 25-mile deep body of water. This could mean Enceladus is capable of harboring life.
Scientists first suspected there was a large volume of liquid water contained within Enceladus in 2005 when Cassini detected jets of salty water vapor escaping from cracks in the southern polar region. Researchers from the US and Italy took a series of readings from close fly-bys of the moon between 2010 and 2012. The Doppler data gathered indicated a large body of dense liquid under the ice. Researchers believe that the liquid ocean is compressed between several miles of ice on the top and a rocky core on the bottom. The Jovian moon Europa is thought to have a similar sub-surface ocean.
Enceladus’ small size makes its subsurface ocean extremely interesting. A moon of that size is unlikely to be producing enough heat of its own to keep water liquid, so heating from tidal stresses on the moon as it orbits Saturn are more probable. Cassini will make several more approaches to Enceladus to study this phenomenon before its mission ends in 2017.