Life on Europa


Our solar system may be host to microbial life on multiple planetary bodies.  Mercury, Mars, Titan, Enceladus, and even some asteroids are plausible candidates.  However, in my opinion Jupiter’s fourth moon Europa represents the most likely candidate for extraterrestrial life in our solar system.  Europa is a moon covered with a 20-kilometer deep ice shelf, but beneath that shelf there is a subsurface ocean 100 kilometers deep.

Astronomers and planetary scientists have proposed traveling to this distant world in the past.  In the 1970s it became evident that Europa would be an ideal location to start our search for life in the solar system.  Since then, several studies have provided us with evidence that Europa could be home to life.  Although Europa is nowhere near our solar system’s goldilock’s zone, it does generate energy from tidal flexing and radioactive decay.  Those sources of energy would not permit a large and diverse photosynthesis-based ecosystem, but it could allow for an ocean of microbial life.  There is also evidence that Europa possesses “great lakes” within its ice shelf that could provide us with a great place to start looking for life.

Despite the promise, funding for an exploratory mission to Europa has been a major roadblock to future research.  It is considerably cheaper (and easier) to send a terrestrial robot to Mars than it is to send a robot that can land on Europa, drill through a dense ice sheet, and navigate a global ocean.  However, I would contend that such a mission should be a top priority for our species.  Understanding the biological nature of our solar system has profound implications for understanding our universe, and our place within the universe.

Robin Hanson of the Future of Humanity Institute views such explorations as imperative for understanding what “great filters” exist between dead matter and cosmic transcendence.  Hanson reasons that such a filter exists because despite the immense size and age of the universe we see no evidence of intelligent life beyond ourselves.  Therefore, it is plausible to suspect that there may be a few major universal obstacles (or “filters”) to the development of such a phenomenon.  Gaining a deeper perspective on where “great filters” exist on the continuum between dead matter and cosmic transcendence could reveal important information about our species probable future.  If our solar system is full of microbial life then we most likely live in a universe filled with simple life; and it increases the possibility that some great filter exists between advanced life and the creation of multi-star civilizations.  However, if our solar system is dead, then perhaps the great filter is the creation of life itself.

Therefore, searching for life in our solar system can be thought of as searching for cosmic omens for our future.

Back to Europa.  Although it seems unlikely that we will design and send a robot to the Galilean moon capable of exploring its deep ocean, it may be possible to understand Europa’s ocean by scanning its surface.

In a research article released yesterday by astronomers Mike Brown and Kevin Hand, they reveal that Europa’s ocean is not isolated (e.g., Brown & Hand, 2013).  Mike Brown stated: “we now have evidence that the ocean and the surface talk to each other and exchange chemicals.”  Kevin Hand echoed this idea claiming: “the surface ice is providing us a window into that potentially habitable ocean below.”

Their study focused on the spectroscopic features on Europa’s surface.  They discovered the presence of magnesium sulfate salt, a mineral that could have only originated from Europa’s subsurface ocean.  From these data they also suggested something even more tantalizing: Europa’s ocean may resemble the composition of Earth’s salty oceans.

Luckily, we may get a closer look at Europa in the 2030s.  The European Space Agency is planning the Jupiter Icy Moon Explorer (JUICE), which is a spacecraft designed to investigate the surface of Ganymede, Callisto, and Europa.  During this mission JUICE should perform the first subsurface sounding of the icy moon to determine the exact thickness of the ice shelf surrounding the subsurface ocean.  How much we will learn about Europa’s chemistry (and biology?) is still unknown, but if the ocean and the surface are “communicating” with each other, it is likely that we will be able to learn a lot from the surface alone.

Either way, the more we find out about Europa, the more unbearably excited I become about future research missions.  Robert Pappalardo, an assistant professor in the Laboratory for Atmospheric and Space Physics at the University of Colorado seems equally optimistic about pushing for further exploration of Europa:

“We’ve spent a bit of time and effort trying to understand if Mars was once a habitable environment.  Europa today, probably, is a habitable environment.  We need to confirm this… but Europa, potentially, has all the ingredients for life… and not just four billion years ago … but today.”

Curiosity could still discover evidence for life on Mars (although I’m not holding my breath).  But all evidence leads me to conclude that Pappalardo is correct.  Europa probably is a habitable environment today.  There may be ecosystems on Europa.  And being able to study an island of life that evolved independently from Earth’s could help us answer so many questions about the universe and humanity’s place within it.  Of course, I am not advocating for the reduced funding for Mars-related exploratory missions.  But more funding for the exploration of Europa could be the best science-investment our species can make at the moment.

You can find out more about our future if you follow Cadell Last on Twitter.

Related Advanced Apes content:

The Curiosity Announcement

Asteroid Apocalypse

A Two-Planet Species


About Cadell Last
Hello. I'm probably drinking coffee and reading.

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