Astronomers prepare to probe Europe’s hidden ocean for life


Beyond Mars and the asteroid belt, half a billion kilometers from the sun, the solar system can appear freezing, dark and lifeless. But scientists believe there is a chance that tiny alien creatures could reside on a distant moon, and you might find them if you look in the right place. For many researchers, this place is Europe, beneath its thick, icy crust.

Planetologists are finding out more about Jupiter’s fourth largest moon, one of the oceanic worlds closest to Earth, places like Titan and Enceladus, the moons of Saturn, which have bodies of salt water and other liquids that could be conducive to the emergence of life. They present new discoveries about the fissured surface, hidden ocean and geological activity in Europe this week at the largest annual planetary conference in the United States, hosted by the American Astronomical Society, held virtually for the second consecutive year. The research serves as a prelude to enticing opportunities for new observations by upcoming missions sent by NASA and the European Space Agency.

“Europe is fantastic. From anywhere in the solar system, outside of Earth, it has the greatest potential, I think, to maintain a habitable environment that could support microbial life, ”says Michael Bland, a US space scientist. Geological Survey in Flagstaff, Arizona. After modeling the dynamic and rocky interior of the moon, Bland believes the conditions of its seabed could be suitable for life, according to new work that he and Catherine Elder, a scientist at NASA’s Jet Propulsion Laboratory, presented at Monday’s conference.

The ocean of Europe is buried under about 10 miles of ice, but that doesn’t necessarily mean it’s too cold for life. As the moon orbits Jupiter, tidal forces generate heat that melts about 5% of the lunar mantle, deep underground. Some of that magma could migrate up to 100 miles through small cracks in the cold, rocky material above, erupting on the seabed, says Bland. If this process did indeed occur, and frequently enough, it would function as hydrothermal vents do on Earth: these volcanic fissures in the seabed provide the energy and chemical ingredients necessary for life, far beyond the reach of light. sun and photosynthesis. Hardy organisms thrive in such dark environments and with high pressure on our world, and maybe they do on others as well.

But for the process to work, the magma must reach the underground sea quickly, before freezing and hardening. Its ascending speed can be barely Fast enough for it to work that way, Bland’s models show, which means there is a chance to live on the seabed of Europe. “It is plausible, but specific conditions must be met, and it is not guaranteed,” he says.

Europe is considered one of the four Galilean moons of Jupiter, first spotted by Galileo Galilei with his pre-NASA telescope four centuries ago. His compatriots include Io, a volcanic, sulfuric, radiation bombarded wasteland near Jupiter, and, orbiting further beyond Europe, the Ganymede Massif and Callisto Crater. The latter two may also harbor subterranean oceans, but if so, the water would lie much deeper under even thicker crusts.

But Europe is unique. Not only is its crust relatively thin, but its surface is covered with thousands of narrow, crisscrossing ridges and crevices, some stretching for hundreds of kilometers. Mapping the images currently available, Michelle Babcock, a planetologist at Georgia Tech in Atlanta, identified about 70 “tortuous ridges” among them: wavy and irregular structures in contrast to the straight and arching ridges that scientists can already explain.

While she does not yet know what causes the convoluted ridges of the ridges, all of the laceration marks on the moon’s exterior could somehow come from its slightly elliptical orbit, which repeatedly pulls it closer, then moves away from Jupiter. “As it orbits Jupiter, the shell is stretched and pulled, and this tidal stress causes fractures and cracks, contributing to many surface features,” Babcock explains. She presented her findings with her colleagues Britney Schmidt and Chase Chivers on Monday.

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