Is Lava Really Forming Dunes On Jupiter’s Closest Moon?

Never-ending fields, towering dunes, and irregular ridges on Io could be formed by winds and lava flowing under a crust of sulfur dioxide ice. A study published on April 19, 2022, in Nature Communications reveals a strange process that was previously ruled out. Science News reports that geological features that resemble dunes have been spotted on Io for more than 20 years. However, these features had been discarded as dunes because Io’s atmosphere is too thin to have winds, and only winds form dunescapes.

Researchers investigated possible wind-blown transport systems happening on Io. The team was inspired by volcanic activity on Earth where bursts of steam occur when lava meets water. While Io has no water, it is abundant in sulphuric oxide frost. On Earth, sulfur dioxide is found as a gas, but on Io, it covers the surface condensing as frost or ice crystals due to the extreme conditions of the moon.

The paper says that shallow “subsurface interactions between lava and Io’s widespread sulfur dioxide (SO2) frost can produce” enough gas to transport sediment, shape the landscape, and create dunes. The moon is now added to “a growing list of bodies” that have a weak atmosphere but where winds can be generated. “In some sense, these [other worlds] are looking more familiar,” George McDonald, lead author of the paper says, adding, “but the more you think about it, they feel more and more exotic.”