The Cassini space probe has tasted the salty spray from an alien ocean that could become a breeding ground for life. New studies have convinced scientists that a sea of liquid water is buried deep beneath the icy surface of Enceladus, one of the moons of giant ringed planet Saturn.
The scientists say it may be several miles deep and that it appears to contain organic compounds that are the essential building blocks of life.
Enceladus, the sixth biggest of Saturn’s moons, is only 300 miles wide and a frozen world. But Saturn’s tidal pull creates energy that makes the interior warm enough for liquid water, making it possibly an ideal environment for life to grow.
The existence of the hidden sea, previously suspected, was confirmed by fresh grains of salt in the outermost of the spectacular rings that encircle Saturn, which lies around 900 million miles from the Sun.
NASA’s robotic Cassini probe, in orbit on an extended mission around Saturn, detected the salt – which is just like that on your table – in the E Ring. European scientists who help run the mission say it is being replenished by jets of ice and vapour spurting from cracks in the moon’s surface. And they say that only a reservoir of liquid water could produce the quantities of salt that Cassini found.
Scientists from NASA and the European Space Agency flew to London to announce their findings, which are published this week in the journal Nature. Mission scientist Frank Postberg, of the Max Planck Institute in Germany, said: “The presence of liquid water with an energy source there enhances the chances of life.”
US colleague John Spencer, of the Southwest Research Institute in Texas, said: “We seem to have all the organic molecules – feedstock that life could use.”
The team cannot say whether life has yet evolved in Enceladus’s oceans. Dr Spencer said: “We don’t yet know how life originated on Earth. But that means it would be useful to find other places where life may have formed.”
Enceladus’s sea is salty for the same reason that Earth’s are – the salt has been dissolved from within the rocks that the water is in contact with.
The existence of the ocean on Enceladus is disputed by a second team of US scientists who have studied the jets from Enceladus from Earth using the Keck 1 telescope on Hawaii and the Anglo-Australian telescope in New South Wales. Professor Nicholas Schneider’s team from the University of Colorado tell Nature that they failed to detect salts in the expelled vapour.
Picture: An impression of the scene on Enceladus, by William K. Hartmann.
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