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rfmcdonaldUniverse Today's Nancy Atkinson reported on the latest findings from Europa. In a paper available online, a pair of astronomers report on evidence not only about Europa's ocean, but about the possible contents of the ocean and the ocean's indirect interactions with the local neighbourhood. Sulfur ejected from Io's volcanoes might be present. The impact of this on the ocean's potential habitability is open to question.
Astronomer Mike Brown and his colleague Kevin Hand might be suffering from “Pump Handle Phobia,” as radio personality Garrison Keillor calls it, where those afflicted just can’t resist putting their tongues on something frozen to see if it will stick. But Brown and Hand are doing it all in the name of science, and they may have found the best evidence yet that Europa has a liquid water ocean beneath its icy surface. Better yet, that vast subsurface ocean may actually shoot up to Europa’s surface, on occasion.
[. . .]
“We now have evidence that Europa’s ocean is not isolated—that the ocean and the surface talk to each other and exchange chemicals,” said Brown, who is an astronomer and professor of planetary astronomy at Caltech. “That means that energy might be going into the ocean, which is important in terms of the possibilities for life there. 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.”
“The surface ice is providing us a window into that potentially habitable ocean below,” said Hand, deputy chief scientist for solar system exploration at JPL.
[. . .]
Salts were detected in the Galileo data – “Not ‘salt’ as in the sodium chloride of your table salt,” Brown wrote in his blog, “Mike Brown’s Planets,” “but more generically ‘salts’ as in ‘things that dissolve in water and stick around when the water evaporates.’”
[. . . N]ow, with data from the Keck Observatory, 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.
[. . .]
The magnesium sulfate appears to be generated by the irradiation of sulfur ejected from the Jovian moon Io and, the authors deduce, magnesium chloride salt originating from Europa’s ocean. Chlorides such as sodium and potassium chlorides, which are expected to be on the Europa surface, are in general not detectable because they have no clear infrared spectral features. But magnesium sulfate is detectable. The authors believe the composition of Europa’s ocean may closely resemble the salty ocean of Earth.
