Broadly speaking, planetary scientists reading the Galileo data assumed Io either has an underground magma ocean or a kind of sponge-like rocky outer mantle soaked in magma.Ī fresh look at the data led Miyazaki and Stevenson concludes it’s the molten sea. Initial analysis of the probe’s magnetic data led to a loose consensus that Io’s mantle-the layer under the moon’s crust-includes a 30-mile thick top layer that should be “molten or partially molten,” according to NASA.Ĭompare this to Earth’s own mantle, as well as the mantles of every other planetary body in the solar system, which are mostly solid and consist largely of ice or superheated rocks. To peer beneath Io’s surface, Miyazaki and Stevenson revisited reams of data from NASA’s Galileo probe, which orbited Jupiter for eight years starting in 1995. But their new peer-reviewed study of the moon’s mantle might be the most thorough yet. It’s been the subject of heated debate for years. Miyazaki and Stevenson aren’t the first scientists to make an educated guess at what lies beneath Io’s potentially 20-mile-thick rocky crust. Only further scrutiny of the 2,200-mile-diameter moon will tell. That possible super-hot sea of melted rock-which is unique in the solar system-could harbor secrets, weird mechanisms for forming moons and planets, and even recipes for exotic alien life. 16 from Yoshinori Miyazaki and David Stevenson, planetary scientists at the California Institute of Technology. That something could be a thick moonwide layer of molten rock-or a “subsurface magma ocean,” according to a new study published in the Planetary Science Journal on Nov. In fact, it’s peppered with so many hundreds of powerful active volcanoes that there must be something unusual beneath its crust. Nat Comdoi: 10.There are more than 200 moons in the solar system, but none quite like Io, the third largest of Jupiter’s 80 moons. Aeolian sediment transport on Io from lava-frost interactions. “In the end, in planetary science, that is what we are trying to do.”Ī paper on the findings was published today in the journal Nature Communications. Lujendra Ojha, a researcher in the Department of Earth and Planetary Sciences at Rutgers University. “Work like this really allows us to understand how the cosmos works,” said Dr. The spacing of the crests and the height-to-width ratios they observed were consistent with trends for dunes seen on Earth and other planets. Once the researchers devised a mechanism by which the dunes could form, they looked to photos of Io’s surface taken by the Solid State Imager on NASA’s Galileo spacecraft for more proof. When lava flows into sulfur dioxide beneath the moon’s surface, its venting is dense and fast moving enough to move grains on Io and possibly enable the formation of large-scale features like dunes. McDonald and colleagues used mathematical equations to simulate the forces on a single grain of basalt or frost and calculate its path. The surface of Io is a mix of black solidified lava flows and sand, flowing ‘effusive’ lava streams, and ‘snows’ of sulfur dioxide.ĭr. “This work tells us that the environments in which dunes are found are considerably more varied than the classical, endless desert landscapes on parts of Earth or on the fictional planet Arrakis in ‘ Dune’,” Dr. “We have proposed, and quantitatively tested, a mechanism by which sand grains can move, and in turn dunes could be forming there.”Ĭurrent scientific understanding dictates that dunes, by their nature, are hills or ridges of sand piled up by the wind.Īnd planetary researchers in previous studies of Io, while describing its surface as containing some dune-like features, concluded the ridges could not be dunes since the forces from winds on Io are weak due to the moon’s low-density atmosphere. George McDonald, a postdoctoral researcher in the Earth and Planetary Sciences Department at Rutgers University. “Our studies point to the possibility of Io as a new ‘dune world’,” said Dr. Image credit: NASA / JPL-Caltech / Rutgers University. Potential dunes on Jupiter’s moon Io: the dark material (lower left) is recently emplaced lava flows, while the repeated, line-like features dominating the image are potential dunes the bright, white areas may be newly emplaced grains as the lava flows vaporize adjacent frost.
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