More Clues to Life in the Oceans — on an Alien Moon, That Is

Computer models of Earth's oceans shed new light on the biological possibilities in Europa's underground waters

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Europa
UIG / Getty Images

Europa

The search for life beyond Earth has generally focused on places that are as much like our home as possible. That’s why the Kepler space mission has gotten headline after headline after headline in recent years, as it discovers Earth-like planets where no one had even looked before. It’s also why NASA and other space agencies have trained their sights so powerfully on Mars, where polar ice caps wax and wane with the seasons and water once flowed freely across the landscape.

The fact, however, say astrobiologists, is that the earthiness of a distant world is less essential for life than is the existence of water there in its liquid state. And that fact is what makes Jupiter’s moon Europa perhaps the most fascinating of all the potentially life-bearing worlds. At nearly 800 million km from the sun compared with Earth’s 150 million km, Europa is covered in a kilometers-thick rind of ice, but beneath it lies a watery ocean. And now, says a new paper in Nature Geoscience, there’s evidence that this ocean is roiling with powerful currents that could be concentrating any life-forms — if they exist — near the moon’s equator. “The conclusions are remarkable,” says Jason Goodman, a planetary scientist at Wheaton College, near Boston, who wrote a commentary accompanying the new study.

That oceans could exist at all on Europa was remarkable enough when the Voyager and Galileo probes found that the moon was indeed covered with ice — as astronomers had long suspected — but that the ice was cracked and jumbled, making it clear that it was floating on what must be a subsurface, moonwide ocean. In retrospect, it made sense: Europa’s solid core flexes with powerful tides imposed by the mammoth planet nearby and by interactions with other moons. Tidal friction generates heat, which keeps the salty ocean permanently unfrozen.

(MORE: A Living Ocean on a Jovian Moon?)

Europa’s icy shell shows its signature cracks everywhere, but the region around the moon’s equator is especially torn up, with huge chunks of ice that have clearly broken away and refrozen in a chaotic pattern known (unsurprisingly) as “chaos terrain.” The reason, theorists have long suspected, is that the upwelling of warmer water from the seafloor would force the ice upward, cracking it. The problem is that most ocean-circulation models to date predict the upwelling and cracking should happen at the poles.

In the new study, University of Texas geophysicist Krista Soderlund and several colleagues used more-sophisticated global ocean-circulation models, originally designed to study the earthly seas, and found instead that the upwelling should happen at the equator — and that given Europa’s spin, heat flow and other factors, it should percolate upward at a brisk 1 m per second or so. “That’s very fast compared with currents on Earth,” says Goodman. “I’m not 100% sure they’re right.”

(MORE: Lasers Could Help Cryobots Melt Through Ice on Europa)

But Soderlund isn’t claiming certainty either. “Others have argued that the chaos terrain formed toward the poles,” she says, where earlier studies have put the upwelling warmer water as well, “and that the ice sheet has reoriented itself. We think our explanation is more convincing.” If nothing else, that explanation has the virtue of simplicity: it’s easier to posit that earlier models were wrong than that an entire global ice layer has been shifting its position.

If Soderlund and her colleagues are right, the implications for a future life-hunting mission could be enormous. “The intensely broken and fragmented ice in the chaos terrain could give us better access to the ocean below,” says Goodman. Plus the upward current could bring nutrients and even living organisms from the oceanic depths to a place, relatively close to the surface, where they’d be within range of an under-ice rover of some sort.

(MORE: A Brand New Ocean on Saturn’s Moon Titan)

Unfortunately, such a mission would be incredibly ambitious, and none is even close to being in the works. The closest we have are the European Space Agency’s Jupiter Icy Moons Explorer, slated for a 2022 launch and arrival in the Jovian system in 2030, and the Jet Propulsion Lab’s Europa Clipper, which hasn’t even been approved yet. Both would be flyby missions, with no landing capability, so a direct search for Europan life is probably decades away.

But if we find a truly Earth-like planet around another star — even the closest star to the sun — it would literally take centuries to get there and start exploring. Compared with that, a jaunt to Europa to drill through a paltry few kilometers of ice in search of alien life sounds like an afternoon’s work.

VIDEO: More Proof That Getting Clobbered by Comets Led to Life

13 comments
DietrichHarris
DietrichHarris

also, it wouldn't take hundreds of year with the beyond light speed technology in the works


eagle11772
eagle11772

Why aren't the editors and fact-checkers (if they still have any) at TIME doing their jobs ? !  The headline, " The Hunt For Lunar Life" is wrong.  "Lunar" specifically refers to our own Moon whose proper name is "Luna".  The headline should read: "The Hunt For Europan Life".

eagle11772
eagle11772

@JuanMOlivaresO  I disagree.  "Luna" refers only to Earth's natural satellite, and no other.  The correct adjective for the search for life on Jupiter's satellite Europa is "Europan".  Furthermore, I hope we never send a probe there to search for life, because every time we find a life form on Earth,either previously unknown, or already known, one of the first things we do is kill it.  The worst thing that ever happened to life on Earth was the arrival of humans. Let's keep the contagion confined to here until it dies out, instead of allowing us to find new life forms away from the Earth to kill.

TimRobinsonAus
TimRobinsonAus

No I don't and neither does %90 of the planet

Constitution - an ideal that's outmoded and dated that is twisted with intent by whatever extreme group within the US can justify their narrow insular view

Bill of Rights - something is still, 50 yrs after segregation, that is a term in name only

Your forefathers - would be embarrassed at the Sodom & Gohmorra type land that their desperate wishes wanted so badly to affect.your 'forefathers' have every quote and comment twisted by every side that they would be shaking their heads at what they started.

Face it, the civil war was a complete waste. Re-split the nation, North & South and if you want one ideal go that way, and the other goes opposite.

PS I'm a man, I don't need a gun to look after my family. Not in a nation where in one in ten thousand owns a handgun, 10 round mag limits and actual weapon inspections. And I'll never worry my kids won't come home in a coffin

eagle11772
eagle11772

@TimRobinsonAus I'd rather nuke you, you commie, because you obviously have NO respect for our U.S. Constitution, our Bill Of Rights, nor our forefathers who died for those Rights, including the Right to own a gun.

TimRobinsonAus
TimRobinsonAus

Honestly words fail me

How about a deal though you or any one in your family are never ever to come here and in return I'll do everything I can to make sure to do likewise

Your children are dying because of that right though I don't understand how so many of you don't make that simple basic connection instead choosing to take the lesser road of denial

Whatever... Deal yeah??

eagle11772
eagle11772

@TimRobinsonAus  So someone who believes in, and supports the U.S. Constitution is a "single minded right wing radical" ?  In the USA, we have a Constitution and  bill Of Rights to protect our RIGHTS FROM the government.  You're opposed to that ?  We have a Second Amendment RIGHT to keep and bear arms to protect us form the government tyranny we have suffered under, in the past and continue to suffer under today.  And for your info, I own and keep in my home, 4 pistols, 3 rifles, 2 shotguns, 2 submachine guns, and 1 .50 caliber machine gun.  Why ?  Because it is our RIGHT to do so, to protect us FROM the government !  Please don't ever come to the USA ya commie !  "from my cold, dead hands........"

TimRobinsonAus
TimRobinsonAus

Thank Christ.... Mate I'd never bother..... Your country's slipped beyond a joke. I think god I live in Australia and single minded right wing radicals like yourself have been disarmed and we live life in peace in relation to your failed experiment of a country

eagle11772
eagle11772

@TimRobinsonAus Then please don't visit here, or live here.  In the U.S., there is NO "Right" to health care, nor should there be.  There IS a "Right" to own a firearm and other weapons, as it SHOULD BE.  "from my cold, dead hands........"

TimRobinsonAus
TimRobinsonAus

And there's the 'moron' tangent..... Politics & Astronomy! Only in America.....nit pick about spelling while you're the only modern country without universal healthcare yet more handguns and guns deaths than ANY modern combat theatre

Oh except Yemen....

Absolute joke of a country

eagle11772
eagle11772

@steelgoat67 That was just a prelude to OBAMACARE. You want to see destruction, you ain't seen nuthin yet !