Jupiter's moon Europa has been spotted erupting again, and NASA says the towering geysers could be the perfect place to check for life with the upcoming Europa Clipper mission.
Over the decades, observations by Voyager 1, Voyager 2 and Galileo found that the moon's subsurface ocean was kept warm by tidal forces. A particularly warm spot seen by Galileo corresponds with where Hubble has spotted plumes, first in 2014 and again in the most recent observations last year.
The 2016 plume-spotting is detailed in a paper published Thursday in The Astrophysical Journal Letters, adding to mounting evidence Europa may be more active than it appears. Hubble also made a separate announcement last year of possible plumes on the surface.
"This latest observation adds to the growing evidence that Europa's complex geology belies an active, maybe habitable, ice shell and ocean," said Hubble team member Britney Schmidt, of the Georgia Institute of Technology, in a statement. "Understanding Europa's plumbing through studies like this gives us a chance to better understand that picture."
The most recently imaged plume rises nearly 62 miles above the icy surface in the same spot where Hubble saw a plume shooting about 30 miles high in 2014.
NASA also announced Thursday that the Cassini spacecraft discovered molecular hydrogen emitting from similar plumes at Saturn's moon Enceladus. That means the sister ocean world has most of the ingredients required to support life.
But NASA astrobiologist Mary Voytek said during a press conference Thursday that between the two moons, she'd bet that the older, Jovian moon is more likely to host life.
"My money for the moment is still on Europa, but it could be on any of these moons and certainly it would be great if it was in all of them."
NASA Director of Planetary Sciences Jim Green said we'll all get a chance to take a closer look at those plumes and what evidence of life they might hold relatively soon. The Europa Clipper mission is set to visit in the next decade.
"If there are plumes on Europa, as we now strongly suspect, with the Europa Clipper we will be ready for them."
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