Beneath Europa's Icy Surface, Ocean Heat Creates 'Chaos Terrains'

Jupiter's moon Europa, one of the few planetary bodies in our solar system that is mostly likely to have the conditions to support some form of life, may have a subsurface ocean with deep currents and circulation patterns that can conduct heat and energy transfers capable of sustaining biological life.

Researchers from the University of Texas at Austin's Institute for Geographics, the Georgia Institute of Technology, and the Max Planck Institute for Solar System Research reported the finding in the journal Nature Geosciences after running a simulation of how the moon's subsurface ocean is predicted to flow.

The idea to create the subsurface model, however, was inspired by a striking and ominously named feature on the moon's surface: chaos terrains. These regions of disrupted surface ice are concentrated in Europa's equatorial region and could be the product of convection in the moon's ice shell and accelerated by heat from it's subsurface ocean.

The researchers contend that the heat transfer may help form diapirs, which are warm, buoyant plumes of ice that rise though the moon's surface's ice shell.

By running a numerical model of Europa's ocean circulation, the researchers were able to account for the location of the chaos terrains and other geologic features on the moon's surface by factoring in the warm rising ocean currents near the equator and the subsiding currents at latitudes closer to the poles.

A similar process has been observed in the creation of marine ice in parts of Antarctica, the researchers said.

"The processes we are modeling on Europa remind us of processes on Earth," said lead author Krista Soderlund.

Britney Schmidt, study co-author and assistant professor at the Georgia Institute of Technology, said the model reveals the "foundational aspects of ocean physics" on Europa, adding that - if the study's hypothesis is correct - the moon's oceans play a key role in shaping it's ice shell.

"That means more evidence that the ocean is there, that it's active, and there are interesting interactions between the ocean and ice shell," Schmidt said, "all of which makes us think about the possibility of life on Europa."

Future missions to the Jovian system, including the European Space Association's JUpiter ICy moons Explorer - or JUICE - mission, will provide the research team with more information to include in subsequent models of the icy world.