ICY SCIENCE: SCIENCE SPACE ASTRONOMY Spring 2014 | Page 31

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about 20 miles beneath the surface. It could be a
layer of rock, but the scientists who are studying
this say they are pretty comfortable in thinking that
it is probably liquid water - a sea that is 6 or 7 miles
deep and covers at least the far southern part of the
moon under the ice - maybe much more.
Left is Enceladus with a wedge taken out, so that we
can see what Cassini scientists think is the internal
structure. Credit: NASA/JPL-Caltech

If that denser-than-ice layer is in fact a sea, this
picture shows how that sea could possibly be the
source of the icy jets. Enceladus is covered by a layer
of ice that is about 20 miles thick. Beneath this is
the probable sea. And beneath that sea is a rocky
core, thought to be based on the mineral silica, like
bedrock on Earth. And if that is what is actually happening on Enceladus, it is an absolute wonderland
for astrobiologists. That sea and silicate rock would
make chemistry that life could live in.
On Earth, rock and liquid water react with each other
in ways that marine biologists and geologists understand very well, because it’s what gives the oceans
so much of its chemistry. That’s why our seas are so
ICY SCIENCE | QTR 2 SPRING 2014