Space scientists have found clues that a fresh place in the solar system may be home to life. They analysed ice volcanoes on a moon of Saturn called Enceladus and discovered powerful new evidence for liquid water beneath its surface.
NASA's Cassini spacecraft flew through the icy plumes and detected negatively charged water molecules - a clear sign that there is an underground sea.
Back home this short-lived type of ion is produced where water is moving, such as in waterfalls or crashing ocean waves.
It was known that the jets contained water but it was not clear before whether this might be liquid.
Cassini scientist Andrew Coates, from University College London's Mullard Space Science Laboratory, led the team that made the new breakthrough, reported in the journal Icarus.
He said the evidence gathered by Cassini pointed to other constituents for life, such as carbon, plus a source of heat to keep the water liquid. It has been suggested that this energy source is the tidal pull of giant Saturn.
Dr Coates said: "While it's no surprise that there is water there, these short-lived ions are extra evidence for sub-surface water. And where there's water, carbon and energy, some of the major ingredients for life are present."
Similar negatively charged ions have been found on another satellite of Saturn, Titan, which is the only moon in the solar system with a thick atmosphere.
The data from Enceladus's icy spray was collected an instrument on Cassini called a plasma spectrometer. It measured the density, temperature and speed of ions and electrons it collected as it flew through the jets.
The Cassini mission has been a major success for U.S. and European scientists since the probe went into orbit around Saturn in 2004.
NASA has just extended the mission's life by seven years. But the UK scientists have been told to abandon their research thanks to swingeing cuts in science spending by the British Government.
Picture: A geyser spewing water from Enceladus, imaged by Cassini. (Photo: NASA).
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