While Earth is mostly covered in water, the universe and scientific hypotheses have often prefigured water, vast oceans of it, to exist in the universe not as we have on the surface of our planet but, in quite a fantastical supposition, underneath it, coursing through a planet or a celestial body like some vital fluid.
Of course most of the time when these strange and fantastic planets are envisioned, they seem to be so far out in deep space that they are almost imaginary but for these ‘underwater’ worlds we have only to look to our backyard for some examples. Europa for instance, one of the six moons of Jupiter, is believed to have an ocean underneath its surface owing to the surface’s smoothness. Similarly, Enceladus, one of the several moons of Saturn, is believed to have an ocean beneath its surface, which NASA probe Cassini investigated as it closely passed by the south pole of the moon today.
The probe passed by the south pole at an altitude of 74km or 46 miles, close enough, according to reports, to “taste” the ice and water vapour jets that were released, apparently emitted by the liquid water ocean of Enceladus.
Cassini is presently using its Ion and Neutral Mass Spectrometer to study the ‘composition, density and variability’ of the ice and water vapour plumes that are being released by the satellite.
Something that scientists are particularly interested about is the apparent evidence of salt that has been detected in the Enceladus plumes. This was reckoned by scientists to be a consequence of the apparent ocean being in contact with the moon’s rocky surface, which suggested that the ocean itself could be rich in minerals and other elements. This in itself could act as a basis or even a medium for life to thrive in, if it already doesn’t.
Last week, Terry Hurford of NASA's Jet Propulsion Laboratory (JPL), announced at the Lunar and Planetary Science Conference (LPSC) in The Woodlands, Texas, that JPL scientists had been able to identify a connection between the geological activity on the surface of Enceladus and Saturn’s gravity. This is important, as it has been seen that Enceladus’ surface has many fissures from which most of the plumes arise.
Cassini is now scheduled to do an even closer flyby of the moon, this time at a distance of 25km or 16 miles and it is expected to do so around October 2015.