The idea that life might exist elsewhere in the universe has fascinated humanity for thousands of years. Salient feature writer Matthew Cunningham explores an obscure underwater world in our neighbourhood where life might very well exist today—and may be discovered within our lifetimes.
In case you haven’t heard, Avatar is awesome. An alien moon circling a distant planet, an exotic swathe of extraterrestrial flora and fauna—oh, and let’s not forget the ten-foot tall sentient beings who dart across the landscape like giant blue ninjas. What makes James Cameron’s masterpiece different, however, is the role of humanity in the interstellar first contact. No longer the hapless victims of an alien invasion, Avatar’s humans are themselves the invaders—the “sky people” from a far-off world. In Cameron’s digitally-created world, we are the aliens.
Strange as it may seem, the idea that humans might one day be extraterrestrial emissaries to an alien world is not entirely far-fetched. Yet almost everywhere we look, the task of finding life seems to be a daunting one. Interstellar distances and that pesky light-speed barrier make our chances of actually meeting alien life beyond our solar system rather slim. Closer to home, scientists speak excitedly about the possibility that microbial life may have existed on Mars millions of years ago.
But there is another candidate for life beyond our world. It is close to home, it contains a body of water larger than all of Earth’s oceans combined, and it has its own internal energy source. It has all the components believed to be necessary for life—and, what’s more, it has them today. Right now. Enter, stage left, Europa.
No, it’s not the band that wrote ‘The Final Countdown’. Europa is one of about sixty satellites of Jupiter, the largest planet in our solar system. It was discovered by Galileo Galilei in 1610 along with the three other ‘Galilean moons’—Io, Callisto and Ganymede. Very little was known about it until the 1970s when NASA’s Voyager missions were able to photograph it up close. What emerged would puzzle scientists. Europa appeared to have an icy outer crust crisscrossed with an ever-shifting landscape of cracks, fissures and craters. Through some unknown process, the surface of Europa seemed to be continually reinventing itself like a bad home renovation show.
The subsequent Galileo mission concluded that Europa’s bi-polar topography is most likely due to an ocean of liquid water beneath the shifting crust of ice. This ocean, heated by Jupiter’s immense tidal pull, is estimated to be as much as 50 kilometres deep. This same tidal pull is the cause of the fiery volcanic activity of Europa’s cousin, Io, and it is highly probable that the same volcanic activity occurs on Europa in the form of volcanic vents on the ocean floor. What’s more, it is theorised that the impact of cosmic rays on Europa’s exterior could convert the ice into oxidizers, providing a supply of oxygen into the subsurface ocean.
Europa contains all of the ingredients necessary for the development of a food chain—liquid water, oxygen, and an energy source. Put them all together, and that’s life, baby.
The grand scheme of things
So why is Europa so important?
“[Europa is] one of the very few places, along with Earth, where all the ingredients for life potentially exist,” says Dr Curt Niebur, NASA Program Scientist for the Europa Jupiter System Mission. “And what we’ve found on Earth is that wherever you have those ingredients for life, life somehow manages to make things work.”
“At the moment we know of just one planet which supports life,” adds Dr Claire Bretherton, Education and Public Programmes Manager at Carter Observatory Wellington. “But if we could find life on one of our own near neighbours this opens up the possibility of many, many more locations in our universe where life may be able to exist.”
For many, this puts Europa at the top of the list in the search for life. “Some scientists rate it higher than Mars as a likely abode of life and more worthy of a major initiative,” explains David Maclennan, President of the New Zealand Spaceflight Association.
“Wherever there is water, there is usually life, even if only of a microscopic nature.”
Niebur stresses that Europa presents a case study of what might be a common phenomenon throughout the universe. “As we’ve explored the universe … we’ve found that these giant gaseous planets like Jupiter are very, very common.
“And while we would not necessarily expect life to arise on these gas ball planets, what we’ve found unexpectedly in our solar system is that the moons orbiting them can actually be quite hospitable places.
“It could be that Earth-like planets are very rare in the universe, but habitable moons around gas giants might be quite commonplace.”
This means that the ‘goldilocks zone’—the narrow strip of space around any given star where the temperature is ‘just right’ for life to arise—may not be as significant as it was originally thought. Europa is well beyond this hypothesised temperate zone, yet it seems to harbour all of the necessary preconditions for life. “We’ve completely turned that [idea] on its ear in the past five to ten years,” says Niebur.
Fly me to the Moon… of Jupiter
If you’re anywhere near as geeky as me, you’re probably wondering the same thing I am—when are we going already?! As it so happens, NASA is currently working on a joint mission with the European Space Agency (ESA) to do just that. The Europa Jupiter System Mission, scheduled to be launched in 2020, is comprised of several spacecraft designed specifically to explore the moons of Jupiter, with a focus on—you guessed it—Europa.
“The goal of the overall mission is to investigate what we call the emergence of habitable worlds around giant planets,” explains Niebur.
“We’re going to study these unexpected oases in the outer solar system—learn how they formed, learn what sustains them, and learn exactly how hospitable they are. And once we understand these things, we can then perhaps learn how unique our solar system is, or if these kind of conditions might be commonplace in the universe.”
NASA has announced that the mission will not include a lander, citing both the complexity of a landing and a lack of knowledge of the Europan terrain. “Simply put, we just don’t understand enough about Europa yet to land there,” says Niebur.
“There are some basic, global science questions that we are asking that can only be answered from orbit. And once we learn enough, we’ll be able to both ask more focused questions that require a lander and, just as importantly, be able to design a vehicle that can survive landing—which is not an easy thing to do.”
Money is also an issue, with the ESA’s contribution facing competition from two other proposed European space missions. President Obama’s recent proposition that NASA focus its energy on a manned mission to Mars may also distract vital funds and expertise from Europa. “At the end of the day, it all comes down to money,” explains Maclennan.
“No bucks, no Buck Rogers.”
Can you dig it?
Like the kid on the first day of school who comes prepared with a full pencil case, NASA is already thinking ahead. In 2009, a team of scientists braved the cold and the threat of rampaging penguins to test out a small submersible vehicle named ENDURANCE in the frozen waters of Lake Bonney, Antarctica. Their key objective was to determine whether it was possible for an automated craft to melt through several kilometres of ice and explore the subterranean ocean underneath it—without any input from human operators.
The mission was a resounding success. “It was very much like being on a space mission at times,” explains Associate Professor Peter Doran, the mission’s lead investigator. “We’d be in the tent in the middle of the lake watching the live feed.
“Part of the excitement was the discovery of new things, part was the fear of getting it stuck … It is now a $5 million plus vehicle and we had little interest in losing it!”
Apart from exploring and taking scientific measurements, ENDURANCE can also render a three-dimensional map of its underwater world. “It was exciting … when we were exploring the terra incognita of the underwater glacier face,” says Doran.
The craft, affectionately nicknamed “The Bot”, is now “on R&R back in Austin Texas”. But will it ever go into outer space? “ENDURANCE itself is too big to ever go to Europa,” states Doran.
“It has just been teaching us how to do autonomous science in an extreme aquatic environment. For the Europa science, the next stage is to scale down.”
Niebur asserts that an ENDURANCE-based mission is the next logical step in the exploration of Europa after the 2020 mission. “I would bet that a lander mission is going to be sitting right near the top of the list for future exploration.”
We could be the “Sky People”!
What exactly might we find beneath Europa’s icy surface? “We really don’t know,” explains Niebur. “You would assume that it would be simple life—single-celled organisms—but we have no way of telling.
“Even in what we would consider drastic and unwelcoming environments on Earth, like around hot springs or volcanic vents, you can see a very complex eco-system arise.”
And how might the discovery of life beyond our planet affect us here on Earth? “How would it NOT affect us?” Niebur asks. “The implications of finding life beyond Earth would be profound in all walks of life.
“It’s impossible to imagine what you could learn scientifically or philosophically or spiritually if life—if ANY kind of life—were discovered beyond Earth.”
Maclennan is somewhat sceptical of the effect it would have on the everyday person. “I really can’t see the average Joe/Jane Bloggs getting too worked up about it.
“I think most people would just shrug their shoulders and go back to watching the real alien life forms on reality TV shows like Survivor or Big Brother.”
At the very least, the prospect that extraterrestrial life might exist within our backyard is an exciting one. And whether or not Europan life is complex in nature or merely the alien equivalent of herpes, it would solve once and for all the riddle of whether we are alone in the universe. If life can evolve independently twice in the same solar system, the chances are that it is prevalent throughout the universe.
And as for me? I’m holding out for alien sea monkeys.