Last week saw an interesting turn of events as over 24 hours scientists finally reached the ancient lake Whillans buried under 800 metres of ice in Antarctica whilst NASA released the latest photograph of one of Saturn’s moons, Titan. What do these two radically different places have in common? They each hold secrets which could unravel a whole new understanding of life as we know it.
Though now a frozen desert with harsh winds and temperatures dropping to nearly -90°C, Antarctica was not always such a hostile environment. Fossils of several animals and plants which thrived in mild conditions have been discovered on the continent suggesting that this largely barren land once flourished with life. Over the past few decades, airborne and satellite surveys have revealed a whole new world beneath the ice with the discovery of nearly 150 sub-glacial lakes – and counting. These lakes are warmed by geothermal energy from below and kept insulated by thick ice sheets flowing across the surface whilst the huge pressure caused by the tonnes of ice above keeps the water from freezing even at -3°C. It is here in these extreme environments, some cut off from the world for millennia, that we could find life in forms never seen before.
Though the depths of Antarctica may seem a long way from space, NASA has taken a special interest in Antarctic drilling projects in order to hunt for ‘extremophiles’ – life forms that thrive in seemingly impossible circumstances. Previously it was thought that life could only be found in the ‘goldilocks zone’ – where temperature, pressure, pH level and many other variables met very specific criteria. However in recent years micro-organisms have been discovered in the most unlikely environments, from the depths of our oceans to the radioactive coolant in nuclear reactors, forcing scientists to rethink how we view life on our planet and indeed in our universe.Now a whole new wave of research and scientific thought is about to break as moons like Saturn’s Enceladus and Titan or even the ice caps of Mars appear more and more hospitable to these wonderful creatures. Enceladus is in many ways similar to Antarctica – its barren, frozen surface hiding an extreme aquatic environment below. However there are differences, for example the atmosphere of Enceladus is virtually non-existent and, fortunately, the possibly life-sustaining waters aren’t locked away quite as tightly as we might at first think. Huge pressures below the surface sometimes cause the ice above to crack and water to rush upwards from below resulting in giant ‘ice volcanoes’ jetting out into space. Any creatures which do inhabit Enceladus would almost certainly live below the surface and these jets allow us to analyse the composition of the oceans below and provide a window into an otherwise unreachable habitat.
Titan is a thorough contrast to its neighbour in almost every way. Here the atmosphere is so thick and the gravity so light that, theoretically, a human could easily fly about using only a set of artificial wings. Carbon and other organic materials are fairly abundant on the moon’s surface and rivers and lakes of liquid ethane and methane are common – some scientists theorise that where life on earth is chiefly orientated around the presence of liquid water, here we might see a very similar ecosystem based on methane.
So why are we wasting time drilling holes in our own ice caps? Surely we should be out there seeking out these extremophiles in our solar system? Well last month NASA’s rover, Curiosity, finally began to do just that as it carried out a test drill on the surface of Mars. However we can never hope to understand what we see out there if we don’t investigate our own planet. NASA’s realisation of this is an extremely encouraging example of how those from different areas of research can come together to learn from one another and to further the advance of their individual studies. Thanks to this collaboration we can see the potential of our solar system much more clearly whilst also learning about our own planet. Nevertheless there are still daunting new frontiers to cross; we know little of Titan’s rocky surface as its atmosphere prevents much study from the earth, Enceladus has oceans still to be explored and Antarctica’s largest and perhaps most promising lake, lake Vostok, is yet to be sampled.
The increased cooperation between these seemingly divergent subjects is yielding exciting results so far and promises of many more to come.The scientific community and indeed humanity as a whole should be waiting with bated breath as over the next few decades we really start to address the mystery of life in our universe.