Scientists have revealed a huge breakthrough in the search for life on other planets.
Nasa’s Cassini spacecraft has provided scientists the first clear evidence that Saturn’s moon Enceladus exhibits signs of present-day hydrothermal activity – similar to that seen in the deep oceans on Earth.
If confirmed, it would make the moon Enceladus the only other known body in the solar system besides Earth where hot water and rocks interact underground.
That activity would make the moon an even more attractive place in the hunt for microbial life.
On Earth, scientists have found weird life forms living in hydrothermal vents on the ocean bottom where there’s no sunlight.
The implications of such activity on a world other than our planet open up unprecedented scientific possibilities, Nasa said.
‘These findings add to the possibility that Enceladus, which contains a subsurface ocean and displays remarkable geologic activity, could contain environments suitable for living organisms,’ said John Grunsfeld astronaut and associate administrator of NASA’s Science Mission Directorate in Washington.
‘The locations in our solar system where extreme environments occur in which life might exist may bring us closer to answering the question: are we alone in the Universe.’
Hydrothermal activity occurs when seawater infiltrates and reacts with a rocky crust and emerges as a heated, mineral-laden solution, a natural occurrence in Earth’s oceans.
According to two science papers, the results are the first clear indications an icy moon may have similar ongoing active processes.
The first paper, published this week in the journal Nature, relates to microscopic grains of rock detected by Cassini in the Saturn system.
An extensive, four-year analysis of data from the spacecraft, computer simulations and laboratory experiments led researchers to the conclusion the tiny grains most likely form when hot water containing dissolved minerals from the moon’s rocky interior travels upward, coming into contact with cooler water.
Temperatures required for the interactions that produce the tiny rock grains would be at least 194 degrees Fahrenheit (90 degrees Celsius).
‘It’s very exciting that we can use these tiny grains of rock, spewed into space by geysers, to tell us about conditions on — and beneath — the ocean floor of an icy moon,’ said the paper’s lead author Sean Hsu, a postdoctoral researcher at the University of Colorado at Boulder.
Cassini’s cosmic dust analyzer (CDA) instrument repeatedly detected miniscule rock particles rich in silicon, even before Cassini entered Saturn’s orbit in 2004.
By process of elimination, the CDA team concluded these particles must be grains of silica, which is found in sand and the mineral quartz on Earth.
The consistent size of the grains observed by Cassini, the largest of which were 6 to 9 nanometers, was the clue that told the researchers a specific process likely was responsible.
On Earth, the most common way to form silica grains of this size is hydrothermal activity under a specific range of conditions; namely, when slightly alkaline and salty water that is super-saturated with silica undergoes a big drop in temperature.
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