We live in incredible times.
Today I checked out the NASA website as I always do and saw a news feature that immediately caught my eye. Under the heading ‘NASA Space Assets Detect Ocean inside Saturn Moon’ the article went on to describe some data which has been returned from the Cassini mission robotic explorer which indicated that it may have detected an ocean underneath the ice that covers one of Saturn’s moons – Enceladus.
To my knowledge, this is the second moon in the Solar System where a liquid ocean has been detected beneath an ice-covered crust. That other moon is Europa, which is a moon of Jupiter.
Both Enceladus and Europa have ejecting plumes of water from in and around their southern polar regions. Since the discovery of these water plumes on Europa, NASA and various other space agencies from around the world, have been keen to send a probe to land on its surface and then drill through the ice mantle and deploy a robotic explorer to explore the oceans that lies beneath.
Now with these findings from the Cassini Huygens probe – which is currently exploring Saturn and its system of moons – they have found another possible future destination to land a probe and explore an ocean that lies beneath a mantle of ice.
From data supplied by Cassini, the ocean is possibly 6 miles (10 kilometres) deep and lies beneath an ice mantle some 25 miles (40 kilometres) thick.
One might pose the question asking how could it be, that in a body orbiting either Jupiter or Saturn, for liquid water to exist? Especially when it lies beneath an ice crust so thick that it could not possibly be caused from what would be very weak, direct sunlight from the Sun?
Well, we need look no further than here on Earth for similar examples of how this might be so. In Antarctica, we have detected two large bodies of water, both found beneath a thick covering of ice. These are Lakes Vostok and Ellsworth and now, careful explorations are being undertaken with the goal of returning uncontaminated samples from these two bodies of water, to see if there is any evidence of life existing in them. Obviously, one of the contributing factors for liquid being in existence underneath the ice in Antarctica, is that the further down you travel under the ice sheets, the warmer the temperature is because of the Earth possessing a warm core.
But the ice covering the body of water which they think exists beneath Europa and Enceladus, is much thicker than that which covers the two lakes under the ice sheets of Antarctica. There is no possibility that these oceans exist as the result of warmth from our Sun. So what other forces are at play which might create an environment for liquid water to exist underneath these two ice-covered moons?
The scientists believe that this is all made possible by the huge tidal forces that are exerted upon these moons by their giant parents – Jupiter and Saturn. Once again, we need look no further than the example of that of our own Moon and how it exerts tidal forces here on Earth, causing the high and low tides which occur daily. Those same forces are also being exerted upon the icy moons of Europa and Enceladus. It is thought that the gravitational pull of these two giant worlds, cause the interiors of these two moons to heat up through a process called tidal kneading. This causes tides to occur in these subsurface oceans producing heat via friction.
What of course is fascinating about these discoveries is that where there is liquid water there could also be life. These two icy worlds have two of the prime ingredients required for life; liquid water and warmth.
Don’t we also need light for life to exist? If that question was asked before we possessed the capability to explore the deepest parts of our own oceans here on Earth, the answer would have probably been yes, we do need light. But within the last 50 years of deep-sea exploration being possible, we have found ample evidence for life being able to exist in abundance without light.
Deep water probes have explored volcanic fumaroles on the ocean floors, spewing out all manner of toxic, hot sulfurous gases and to everyone’s amazement, they are supporting many forms of life forms, happily feeding off these materials being ejected from these deep ocean vents. These life forms resemble none that we have ever seen before and defy any models of life forms that exist on land. They need no light and feed off a diet of toxic gases and emissions that would most certainly kill any other known life forms.
Armed with these examples from our home planet of ‘alien’ life forms existing in the deepest reaches of our oceans, all bets are now off that life could exist within the oceans of these two moons, many millions of miles away from the warmth of the Sun.
This is what makes the exploration of those two pre-historic, pristine bodies of water under the Antarctic ice so intriguing. They would be the nearest examples that we have here on Earth to the suspected oceans that exist under the ice mantles of Europa and Enceladus. Much care is being taken to make sure that the drills that they are using to reach these lakes, do not contaminate the waters by introducing microbiological organisms from the world above. If we were to find any traces of life from samples taken from these waters, it would further the case that it could also be a possibility that the nearest other life forms known to man, may not be in far distant galaxies, but right here within our own Solar System.
So what exciting times we do indeed live in. Hopefully NASA and/or one of the other space agencies here on Earth, will sometime soon send further robotic emissaries to these two worlds, which will be able to land and then go ahead to burrow through the ice and find out if indeed, we are not alone.
I am minded to think back to the Arthur C. Clarke science fiction novel ‘2010’. The benevolent aliens who had left the ‘Monolith’ on the Moon and further in Jupiter orbit, had detected life existing on Europa and as they had with early life forms here on Earth, decided to protect and nurture it to give it a chance to develop on its own. To enable this to happen, required them altering the chemical composition of Jupiter and turning it into a star in its own right, with the moons orbiting it becoming in effect, a mini Jovian solar system. The heat from the new sun then melted the ice crust of Europa and the microbiological life that existed beneath in the oceans, then had all the ingredients necessary to develop into life forms of their own.
As the humans departed Jupiter space, witnessing this incredible event unfold before their eyes, a message was displayed on all the computer screens on the departing spacecraft. The message was:
“ALL THESE WORLDS ARE YOURS EXCEPT EUROPA, ATTEMPT NO LANDING THERE”
It gives me the goosepimples thinking if this work of fiction might one day become reality . . .