Anyone who has read Arthur C. Clarke’s 1982 book 2010: Odyssey Two will be familiar with the phrase, “ALL THESE WORLDS ARE YOURS EXCEPT EUROPA. ATTEMPT NO LANDING THERE,” and the idea of possible life on Europa, Jupiter’s sixth-closest moon. But the possibility of such life is looking less like science fiction and more like science fact (or at least science possible).
Europa is slightly smaller than Earth’s moon, and it has a tenuous atmosphere composed of oxygen. Europa is covered in a layer of ice, and it has an iron core. Most important for the purposes of this article, scientists theorize that the forces of tidal flexing (as Europa orbits Jupiter, it also interacts with the other moons) might generate enough energy to melt the subsurface ice, transforming it into a vast ocean.
Until the late 1970s or so, it was thought that life could not exist at the bottom of Earth’s oceans, due to the absence of sunlight. However, in 1977, an entirely alternate food chain was discovered in the depths of the Galapagos Rift. This alternate food chain was based not on photosynthesis, but chemosynthesis. As described on the Europa Wikipedia page linked to above (yes, it’s Wikipedia, so take this with a grain of salt, but I find the description clear and straightforward), the food chain is summarized this way:
The basis for this food chain was a form of bacterium that derived its energy from oxidization of reactive chemicals, such as hydrogen or hydrogen sulfide, that bubbled up from the Earth’s interior. This chemosynthesis revolutionized the study of biology by revealing that life need not be sun-dependent; it only requires water and an energy gradient in order to exist.
As we have continued to explore Earth’s oceans, we have discovered a vast variety of life. Recently, exploration of the Marianas Trench (6.6 miles deep) have found single-celled creatures approximately four inches across called xenophyophores. These xenophyophores are also host to a variety of multicellular creatures. In other words, we are in the midst of greatly expanding our understanding of Earth’s biodiversity.
Scientists currently have many theories about the type of life that may exist on Europa, if any exists at all. Don’t hold your breath for vast, underwater civilizations like in the movie The Abyss. Instead, simple bacterium or algae are more likely. But Richard Greenberg of the University of Arizona has theorized that Europa’s oceans might contain enough oxygen to support “macrofauna” such as fish-like creatures.
Of course, we’ll never know either way until we explore Europa, despite HAL’s warnings in Clarke’s novel. At the recent TAM 9 conference, astrophysicist and Hayden Planetarium director Neil deGrasse Tyson said sending a submarine below Europa’s surface would be his dream mission (the video of the panel is long, but definitely worth it).
What if such a mission were to take place? Sure, it may not be as sexy as astronauts landing on the Moon or Mars, but what if NASA hosted a livestream of the submarine’s video feed? What would be humanity’s reaction to alien life, even if simple bacterium? What would it mean for everyone to see evidence that life exists beyond Earth? Would it inspire a new round of manned space exploration? Would Europa’s proto-atmosphere and oceans make it a prime location for a manned base? Or would it inspire denial, fear, and religious-tinged panic?
On the other hand, what if Europa’s waters were heavily explored and no evidence of life was found? How would humanity react, if one of the best chances for alien life came up empty? Would humanity even care? Would NASA’s budget get cut even more?
What do you think? Should we explore Europa? How would we react to what we find, even if it’s nothing?