Jupiter’s Europa: New Evidence for Life-sustaining Ocean?

March 5th, 2013

Europa's icy face - an ocean underneath? Credit: NASA/JPL-Caltech

Europa is an icy moon of Jupiter – and may well be an astrobiology target of a future spacecraft mission.

Thanks to NASA’s Galileo mission, that spacecraft showed Europa to be covered with a veneer of ice, a cracked façade that may cover a global ocean over 60 miles (100 kilometers) deep.

New research by Mike Brown, an astronomer at the California Institute of Technology (Caltech) and Kevin Hand from NASA’s Jet Propulsion Laboratory (JPL) have reported they’ve found the strongest evidence yet that salty water from the vast liquid ocean beneath Europa’s frozen exterior actually makes its way to the surface.

The scientists made use of special gear outfitted to the Keck II telescope on Mauna Kea in Hawaii.Brown and Hand have identified a spectroscopic feature on Europa’s surface that indicates the presence of a magnesium sulfate salt, a mineral called epsomite, that could have formed by oxidation of a mineral likely originating from the ocean below.

“We now have evidence that Europa’s ocean is not isolated…that the ocean and the surface talk to each other and exchange chemicals,” says Brown in a Caltech press statement.

“That means that energy might be going into the ocean, which is important in terms of the possibilities for life there,” Brown said. “It also means that if you’d like to know what’s in the ocean, you can just go to the surface and scrape some off.”

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Brown adds that the two scientists believe the composition of Europa’s sea closely resembles the salty ocean of Earth. “If you could go swim down in the ocean of Europa and taste it, it would just taste like normal old salt,” he says.

JPL’s Hand said, from an astrobiology standpoint, Europa is considered a premier target in the search for life beyond Earth.

Indeed, a NASA-funded study team led by JPL and the Johns Hopkins University Applied Physics Laboratory are working with the scientific community to identify options to explore Europa further.

“If we’ve learned anything about life on Earth, it’s that where there’s liquid water, there’s generally life,” Hand says. “And of course our ocean is a nice salty ocean. Perhaps Europa’s salty ocean is also a wonderful place for life.”

Note: The new research has been accepted for publication in The Astronomical Journal, a paper titled “Salts and radiation products on the surface of Europa.”

The work was supported, in part, by the NASA Astrobiology Institute through the Astrobiology of Icy Worlds node at JPL.

By Leonard David via Caltech/ Kimm Fesenmaier
Credit: NASA/JPL-Caltech