Jupiter’s moon Io is the most volcanically active body in the Solar System, and the body that is known to be most rapidly resurfaced. Surface modification on Io has to date been attributed almost exclusively to lava emplacement and volcanic plume deposits. In new research, planetary scientists from Rutgers University and elsewhere performed the first measurements of the dimensions of linear features in images from NASA’s Galileo probe, previously termed ‘ridges,’ which demonstrate certain similarities to dunes on other planetary bodies.
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. Image credit: NASA / JPL-Caltech / Rutgers University.
“Our studies point to the possibility of Io as a new ‘dune world’,” said Dr. George McDonald, a postdoctoral researcher in the Earth and Planetary Sciences Department at Rutgers University.
“We have proposed, and quantitatively tested, a mechanism by which sand grains can move, and in turn dunes could be forming there.”
Current scientific understanding dictates that dunes, by their nature, are hills or ridges of sand piled up by the wind.
And 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.
“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. McDonald said.
The surface of Io is a mix of black solidified lava flows and sand, flowing ‘effusive’ lava streams, and ‘snows’ of sulfur dioxide.
Dr. McDonald and colleagues used mathematical equations to simulate the forces on a single grain of basalt or frost and calculate its path.
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.
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.
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.
“Work like this really allows us to understand how the cosmos works,” said Dr. Lujendra Ojha, a researcher in the Department of Earth and Planetary Sciences at Rutgers University.
“In the end, in planetary science, that is what we are trying to do.”
A paper on the findings was published today in the journal Nature Communications.
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G.D. McDonald et al. 2022. Aeolian sediment transport on Io from lava-frost interactions. Nat Commun 13, 2076; doi: 10.1038/s41467-022-29682-x
