Jordan Healey discusses new research which indicates the presence of characteristics closely associated with hosting life on one of Saturn’s moons
The Cassini mission, a collaboration between NASA, the European Space Agency and the Italian Space Agency, has been a huge success. The first spacecraft to orbit Saturn has revealed a huge amount of information about the planet and its enigmatic moons over the past decade. The mission is officially set to end on September 15th 2017, nearly 20 years after it began and the ‘grand finale’ of the mission is due in just a few days’ time. This ‘grand finale’ will involve the spacecraft diving in and out of a new set of orbits between the planet and its rings (which will be the first time this region will be explored) before it is finally crashed into the surface of the planet, hopefully gathering huge amounts of data and taking many pictures of this unexplored region in its final moments.
One of Saturn’s moons Enceladus caught a lot of attention as early as 2005 when the spacecraft detected what could be an atmosphere on the icy moon. It then returned after a few months had passed and was able to confirm the presence of water vapour clouds in the atmosphere and then liquid water on the surface in 2006. This key factor for enabling the existence of life has made it a focal point for further study into the increasingly publicised search for extraterrestrial life in our own Solar System. Last week there was an even more significant announcement regarding these developments. Not only have scientists shown that hydrogen gas exists on the moon, but there was also evidence to suggest that hydrothermal activity occurring at the seafloor may have been the source. Scientists currently attribute the energy for the earliest known life, cyanobacteria, to exist on our planet to hydrothermal activity so this announcement has gained a lot of attention inside and outside of the scientific community over the past few days. However, what does the discovery of hydrogen gas mean in all of this and what does the future hold for the study of Enceladus considering the Cassini spacecraft is set to destroy itself in the coming months?
Hydrogen gas is a source of energy that would be necessary for providing energy to a system deprived of sunlight since it plays a role in converting volcanic carbon dioxide into methane; the simplest organic molecule. Chris McKay, of the NASA Ames Research Centre in California, in an interview with New Scientist, suggested that if we took methane-feeding lifeforms from the sea floor today and put them on Enceladus they should be able to survive. These life forms, called methanogens, are able to thrive in the extreme environments of the ocean floor so they should be able to survive in the hostile environments of Enceladus too. The next logical question that has intrigued so many people over the past few days is surely: could home-grown life also potentially exist on Enceladus given its habitable environment?
While it’s probably our current best bet on discovering extraterrestrial life, unfortunately, Enceladus will not be able to be studied in depth for a long time once the Cassini spacecraft is destroyed (in a move to protect the potentially life-harbouring ice moons from being crashed into when the spacecraft runs out of fuel). In addition, having the potential to facilitate life does not necessarily mean there will be since so many other complex factors come into play. Assuming NASA is able to send a new spacecraft to Enceladus following their next major wave of funding; it will not reach there until the late 2020s at the earliest so it will be a while before we get any long awaited confirmation of extraterrestrial life. If, however, the time comes and we do discover alien life on Enceladus, it will have an unprecedented effect on our understanding of many different fields of science and be yet another huge discovery we could be fortunate enough to witness, giving us all something to look forward to in the future.