A new way to form dunes on various celestial surfaces

Scientists have long wondered how Jupiter’s innermost moon, Io, had curved ridges as high as those seen in movies like “Dune.” Now, a Rutgers research study has provided a new explanation for how dunes can form even on a surface as icy and choppy as Io.

The study, published in the journal Nature communication, is based on a study of the physical processes that control the motion of grains along with an analysis of images from NASA’s 14-year Galileo spacecraft mission, which allowed the creation of the first detailed maps of the moons of Jupiter. The new study should expand our scientific understanding of the geological features of these planet-like worlds.

“Our studies point to the possibility of Io as a new ‘dune world,'” said lead author George McDonald, a postdoctoral researcher in Rutgers’ Department of Earth and Planetary Sciences. “We have proposed, and tested quantitatively, a mechanism by which grains of sand can move and, in turn, dunes could form.”

Current scientific knowledge says that dunes, by their nature, are hills or ridges of sand piled up by the wind. And scientists in previous Io studies, while describing their surface as dune-like features, concluded that ridges could not be dunes because the wind forces at Io are weak due to low density. of the atmosphere of the moon.

“This work tells us that the environments in which the dunes are located are considerably more varied than the classic and endless desert landscapes in parts of the Earth or on the fictional planet Arrakis in‘ Dune, ’” McDonald said.

The Galileo mission, which lasted from 1989 to 2003, recorded so many scientific developments that researchers are still studying the data it collected today. One of the key ideas extracted from the data was the high extent of volcanic activity in Io, so much so that its volcanoes reappear repeatedly and rapidly in the small world.

The surface of Io is a mixture of black and sand solidified lava flows, “effusive” lava flows, and “snow” of sulfur dioxide. Scientists used mathematical equations to simulate forces on a single grain of basalt or frost and calculate their trajectory. As the lava flows into the sulfur dioxide beneath the moon’s surface, its ventilation is “dense and fast enough to move the grains to Io and eventually allow the formation of large-scale features like dunes.” dir McDonald.

Once the researchers devised a mechanism by which the dunes could form, they turned to photos of the surface of Io taken by the Galileo spacecraft for further testing. The ridge spacing and aspect ratios they observed were consistent with the dune patterns observed on Earth and other planets.

“Working like this allows us to really understand how the cosmos works,” said Lujendra Ojha, co-author and assistant professor in the Department of Earth and Planetary Sciences. “At the end of the day, in planetary science, that’s what we’re trying to do. »

The article also included authors from the University of Oregon, the Massachusetts Institute of Technology, the A&M University of Texas, and the Jet Propulsion Laboratory of the California Institute of Technology.

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Materials provided by Rutgers University. Original written by Kitta MacPherson. Note: Content can be edited by style and length.

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