On the 15th September 2017, a twenty year long mission by the NASA Cassini space probe came to an end when it plunged into Saturn’s upper atmosphere.
Launching in 1997, and planned for years beforehand, Cassini was intended to study as many moons as possible, in particular, those surrounding Jupiter and Saturn. One of the objects of the mission was also to learn more about the possible existence and availability of water in on the astral bodies it passed. In this regard alone, the many pictures taken by Cassini produced much revealing and exciting information.
Thanks to Cassini’s observations of Saturn’s largest moon, Titan, scientists have discovered that it possesses lakes, rivers, channels, dunes, rain, clouds, mountains and possibly volcanoes, just like Earth. Another of Saturn’s moons, Enceladus, revealed sprays of icy particles erupting from its surface; jets of ice-water three times taller than the width of Enceladus itself. Further, Cassini was able to get as close as 15 miles from this moon’s surface and determine that there was a global subsurface ocean, which might have the conditions suitable for sustaining life.
One of Jupiter’s moons, Europa, also shows extensive evidence of water. Its surface is covered with a layer of frozen ice, which scientists again believe hides an ocean beneath. As a consequence, Europa is often touted as a possible abode for life. Cynthia Phillips, a Europa project scientist at the Jet Propulsion Laboratory, believes there is a lot of indirect evidence for a liquid ocean, “We’re almost certain one is there…” she told Space.com “… the mass of Europa, combined with its density… gives a figure close to one [gram per cubic centimetre] …water is the only material like that.”
The question of the amount (or existence) of water in space has long been debated, often with a view to it sustaining mankind in the future. Mars in particular has attracted a lot of speculation of this nature. Images from the so-called Red Planet have shown dried up riverbeds, lakes, and coastlines across its surface. Recent satellite images from the Aeolis Dorsa region of Mars have uncovered new evidence of the densest river deposits recorded to date. These deposits are believed to date from water that flowed on the surface over 3.5 billion years ago. The channels and ridges formed by these ancient rivers are being studied in the hope that we can better understand the two evolutionary cycles of Mars and Earth, to see if links can be made.
With Cassini’s mission generating a colossal amount of data, scientists now have the opportunity to learn more about the environment of space, the evolution of numerous planetary moons, and the amount of water those moons and their commanding planets could hold now, or may have done in the past.
Will this information lead to mankind ultimately growing food- or even living- in Space? Only time will tell.
Dr Kathryn Bates is a graduate of archaeology and history. She has excavated across the world as an archaeologist, and tutored medieval history at Leicester University. She joined the administrative team at Oxford Open Learning twelve years ago. Alongside her distance learning work, Dr Bates is a bestselling novelist, and an itinerant creative writing tutor for primary school children.