The existence of aliens has long been confined to science fiction, having been judged as an unlikely possibility in our solar system following the exploration of our planetary neighbours in the last half century. However, recent evidence of water vapour on Jupiter’s moon, Europa, may re-ignite the search for extra-terrestrial life. This is with the potential discovery of liquid water, a key component for supporting life, under Europa’s icy surface.
The crucial evidence for Europa potentially holding the key ingredient of water dates back over 20 years, to NASA’s Galileo probe that orbited Jupiter between 1995 and 2003, and passed by Europa in that time. From the fly-by, NASA scientists were able to detect disturbances to Jupiter’s magnetic field when the gas giant was in proximity to Europa. The scientists hypothesised that an electrically conductive fluid, which is needed for the generation of a magnetic field, was present below Europa’s icy crust. They went on to suggest that this conductive fluid is in the form of a salty ocean. This is an idea which was given more credit following findings from 2013, which found hydrogen and oxygen – the key components of water – in plumes arising from Europa. These plumes of suspected water vapour were imaged three years later by the Hubble telescope, confirming the previous evidence which found that water, although present in a vapour rather than liquid form, was present on Europa. However, concrete evidence of a subsurface ocean is yet to be found, although this is one of the aims of NASA’s Europa Clipper mission, forecasted for launch in the 2020’s.
If liquid water is found under the surface of Europa, the potential presence of alien lifeforms existing multiplies. The organisms existing in the inhospitably cold conditions of Europa are unlikely to be the little green men popular culture often portrays aliens as. Instead, life on other planets is likely to take a much more primitive form, such as a single cellular organism, perhaps similar to extremophiles we see here on Earth. Earth is populated with many bacteria that live at the very extremes of our planet’s diverse environment, such as Psychorophiles, who can live in Antarctic and deep sea habitats. Perhaps a similar kind of organism could be found within the rumoured subsurface ocean of Europa, adapted to the unforgiving cold and darkness. But, this kind of in-depth exploration is something for future missions to explore. Currently, NASA and ESA each have plans to explore Europa’s potential of harbouring life through performing fly-bys of the icy moon within the next decade. This is something which Xianzhe Jia, a space scientist at the University of Michigan, said will “provide crucial information to us to assess Europa’s potential for life”.
Even if Europa doesn’t contain alien inhabitants, should it have liquid water, it could be a potential host for humanity. Prominent scientists, such as Michio Kaku, one of the founders of string theory, claim that living off-planet is the key to the survival of our species. Kaku remarks that the only reason the dinosaurs are not around today is because they lacked a space programme – if they had one, maybe the asteroid wouldn’t have wiped them out. While asteroids are a much less likely cause for humanity to die out, something like climate change just might. Becoming a species that lives on more than one planet may seem logical, but one issue remains; finding planets either within or outside of our solar system that have the necessary qualities to support life has been next to impossible. The existence of water on Europa is an appealing idea – other exoplanets meeting the criteria of sustaining life are found in other solar systems, while Europa is practically our neighbour. Europa will not be the easiest moon to inhabit, with an icy surface and an average surface temperature of -142oC, humanity would find the conditions less than comfortable. The potential for humans colonising Europa, or for discovering alien life there depends on the scientific research of the next decade, and the upcoming missions by space agencies around the world highlights the exciting steps being taken in the exploration of our own diverse solar system.
Interview with Michio Kaku, one of the founders of string theory: https://www.nationalgeographic.com/news/2018/02/there-s-only-one-way-for-humanity-to-survive--go-to-mars-/
Extremophiles on Earth: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1456908/
Europa’s temperature: https://europa.nasa.gov/resources/114/daytime-temperatures-on-europa/
Other exoplanets that may potentially support life: https://www.space.com/earth-size-exoplanet-habitable-zone-kepler.html