A major scientific discovery was made this week as scientists uncovered overwhelming evidence indicating the presence of a ‘great lake’ on Saturn’s moon Enceladus. The discovery is important because it marks Enceladus as being a possible site for life existing outside of our own planet.
Initially, icy material was seen being squirted into space from an odd ‘striped’ pattern on the moon’s southern pole. It was theorized that this material was water being ejected from a large body of liquid H20 on the moon’s surface. This week, measurements from NASA’s Cassini probe revealed the water’s gravitational signal, effectively confirming the theory. The Cassini probe even sampled the water as it was ejected into space.
Professor Luciano Less, of the Sapienza University of Rome, who was interviewed on the subject by BBC news, said, “The measurements that we have done are consistent with the existence of a large water reservoir about the size (volume) of Lake Superior in North America,”
To add context to this statement, Lake Superior is the largest freshwater lake in the world by surface and the third largest in the world by volume. It reaches depths of 147 metres and has an approximate volume of 12,000 Km3. It also plays home to over 80 different species of fish.
Data extracted from the probe suggests that the water is about 40km underneath Enceladus’ icy surface.
Enceladus is locked in an eccentric orbit around its parent planet; this means that the moon’s orbit is non-circular and it therefore follows that Saturn’s gravity will have the effect of melting the ice in some places and freezing any liquid found in others.
There are a lot of places in our solar system that possibly house liquid water, but not as many where that water can come into contact with rock. Rock is important because rocks release minerals and salts into the water – and these materials are among the key building blocks of life.
Professor Andrew Coates of the UCL-Mullard Space Science Laboratory was also interviewed for BBC news, he remained positive regarding the possibility of microbal life on Enceladus. Prof Coates said, “I think Enceladus has gone to the top of the charts in terms of a place where there could be life. It’s got several of the things which you need for life – there’s certainly the presence of heat, there’s liquid water in this ocean, there’s organics and that type of chemistry going on. The only question is, has there been enough time for life to develop?”
However, as Professor David Stevenson, from the California Institute of Technology, pointed out “we don’t know whether the ocean is being added to at present or is freezing up”. It is theoretically possible that the great body of water confirmed this week has been there for 100 million years, but it is also potentially a far more recent development. At present, no one knows for sure.