The surface of Saturn’s moon Enceladus shows evidence of ongoing geological activity
Alien life could have evolved on one of Saturn’s moons, scientists say.
They have found evidence that seas may lie beneath the frozen surface of Enceladus – the planet’s sixth biggest moon.
It follows the discovery of a giant plume of salt water and ice spurting hundreds of miles into space from the moon’s surface.
Nasa’s Cassini spacecraft discovered the ‘ice geyser’ near the south pole of Enceladus, one of Saturn’s 60 moons, in 2005.
Since then, scientists have debated whether this meant that Enceladus – a ball of ice and rock with a diameter of only 310 miles – was hiding a reservoir of liquid water.
Dr Frank Postberg, of the Max Planck Institute for Nuclear Physics in Heidelberg, studied data from Cassini’s cosmic dust collector and discovered it had picked up salty grains of ice from the geyser.
Their presence is powerful evidence of salty lakes, reservoirs or seas within Enceladus.
The findings, published in the journal Nature, raise the prospect that alien fish and other marine life might have evolved there.
This picture shows water vapor jets erupting from Saturn’s icy moon, Enceladus
‘If you have this large amount of water in contact with a rocky core and you have heat, then you have very good conditions,’ Dr Postberg said.
‘On top of that we measured a slightly alkaline pH value, which is very good for the formation of complex organic molecules.’
He believes the ice geyser comes from a liquid underground source – most likely a deep cavern reservoir.
The water is kept liquid by heat generated by Saturn’s tidal pull.
Until recently, most astronomers had ruled out the possibility of aliens in the Solar System, arguing that other planets were either too hot, too cold or had atmospheres that were unsuitable for life.
But robotic space missions over the last few decades have shown that conditions for marine life could exist on some of the water moons orbiting Saturn and Jupiter.
The ice geyser spurts from fractures, called tiger stripes, on the moon’s south pole.
Commenting on the research, US planetary scientist Dr John Spencer, from the Southwest Research Institute in Boulder, Colorado, said: ‘Our picture of its subsurface must now be expanded to include the possibility of misty ice caverns floored with pools and channels of salty water, lurking beneath the tiger stripes.
‘What else may lurk in those salty pools, if they exist, remains to be seen.’
Enceladus is one of only three moons in the Solar System that generate eruptions of vapour and dust.
Aside from the Earth, Mars and Jupiter’s moon Europa, it is one of the only places in the solar system where astronomers have found evidence of water.
Dr Postberg said: ‘The original picture of the plumes as violently erupting Yellowstone-like geysers is changing.
‘They seem more like steady jets of vapour and ice fed by a large water reservoir.
‘However, we can’t decide yet if the water is currently ‘trapped’ within huge pockets in Enceladus’ thick crust ice or still connected to a large ocean in contact with the rocky core.’
A second study in Nature – from the University of Colardo – suggests there are no salty oceans on the moon – and that the geysers spew from deep caverns of water.
Using telescopes on the Earth, astronomers found no evidence of sodium slats in the plumes from Enceladus.
That suggests the vapour originates from caverns deep within the moon where water evaporates slowly and contains little salt.
Via Daily Mail