Boost for the chances of life? Jupiter-moon Europa may plate tectonics

Jupiter is the ocean, the inns of the moon have plate tectonics, a new study suggests.

(NASA/JPL-Caltech/SETI Institute)

The case for plate tectonics on Jupiter’s ocean-harboring moon Europa becoming stronger and stronger.

Scientists had already spotted geological signs that the plates in the moon’s ice shell can dive under each other in the direction of the moon’s buried ocean. Now, a new study suggests that such “subduction” is indeed possible in Europe, and shows how the phenomenon could happen.

The new results should intrigue astrobiologists and everyone who hopes that the Earth is not the only inhabited world in the solar system. [Photos: Europa, Mysterious Icy Moon of Jupiter]

“If, indeed, there is life in the ocean, subduction provides a way for the supply of the nutrients it would need,” study lead author Brandon Johnson, an assistant professor in the Department of Earth, Environmental and Planetary Sciences at Brown University in Rhode Island, said in a statement.

More Of

  • Photos: Europa, Mysterious Icy Moon of Jupiter

  • Europe

  • Journal of Geophysical Research: Planets

These nutrients are antioxidants, electron-stripping substances that are common in Europe’s surface and that could provide a source of energy for life, the researchers said.

Here on Earth, subduction is primarily driven by the temperature differences between relatively cool (and therefore dense) rocky plates and the superhot surrounding mantle. Thermal gradients could not be the prime mover in Europe, but: Ice sheets would warm pigeon, quickly equilibrating to the temperature of the ice below, study team members said.

But that does not mean that subduction can not occur on the Jupiter moon, Johnson and his colleagues found. Their computer models suggest that the Europan ice sheets can indeed swim, if they are saltier than their surroundings.

“Adding salt to an ice-sheet would be like adding small weights, because the salt is denser than ice,” Johnson said in the same statement. “So, instead of temperature, we show that the differences in the salinity of the ice can create subduction happen in Europe.”

Such differences may exist in the moon’s ice shell, one of the researchers said. Upwelling of the underground ocean could deposit salt patchily on the surface, such as eruptions of cryovolcanoes, the scientists said.

The presence of plate tectonics on Europe can help us to learn more about our own planet, as well as the frosty moon, Brown said.

“It is fascinating to think that we might have plate tectonics anywhere else than on Earth,” he said. “Think from the point of view of comparative planetology, as we can now the study of the tectonics in these very different places, it could help us understand how plate tectonics started on the Earth.”

The new study has been accepted for publication in the Journal of Geophysical Research: Planets.

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