Water Plumes on Europa
Since the Voyager spacecraft flybys in the late 1970’s we have known that Europa is one of the most enigmatic objects in the solar system. We already suspected that the moon was covered in ice and the space craft data implied that tides on the moon raised by the much more massive Jupiter would be enormous. On Io, the tides produce hundreds of active volcanos.
Europa is further from Jupiter and the tides smaller: the planet is “only” squashed and stretched by 100m as it moved through Jupiter’s magnetic field. While Voyager found the surface more tranquil, scientists deduced there must be a vast ocean of liquid water, warmed by the tides, under the thin crust. Europa is the first extra-terrestrial planet we have found with vast quantities of liquid water present and a prime target to look for extra-terrestrial life.
There has been much talk of going to Europa and drilling through the ice to examine this ocean. This would be a perilous journey – the intense radiation from Jupiter would endanger the spacecraft. Landing and drilling through the crust would be fraught with problems (e.g. we don't know the ice thickness), not least the risk of contaminating Europa with earthly microbes.
The discovery of plumes spewing through the surface of Europa and reaching altitudes of hundreds of kilometres means that we now have a safer way of examining the ocean. A spacecraft flyby could collect a sample we can examine further away from Jupiter in a less hostile environment. An on-board lab could then look for signatures of life. This would be maybe a simpler but still a challenging mission.
So what would the detection of a few bugs in an ocean deep underground on a distant moon really tell us and why go to all this trouble. Firstly, we could conclude that unless there is something special about our solar system then could be ubiquitous in the Universe.
Secondly it would demonstrate that life could find a way in unexpected places. Overall it would be a first step in finding our place in the universe.