![]() Cycloidal ridges and ridge complexes share many of these characteristics and along-strike transitions between ridge morphologies are not uncommon, suggesting that a single process may be active in the formation of all ridge types 18, 19. These ridges may extend for hundreds of kilometers and include some of the oldest features visible on the surface, with frequent cross-cutting implying numerous formation cycles over Europa’s history 15, 16. Of these, double ridges are the most common, consisting of quasi-symmetric ridge pairs flanking a medial trough 15, 16, with height to peak-to-peak distance ratios <0.58 17. Some of the primary observational constraints on these subsurface processes are their expressions in the surface morphologies imaged by Voyager and Galileo.Įuropa’s surface is young 12 and geologically active 13, 14, displaying a wide variety of landforms including ridges, troughs, bands, lenticulae, and chaos terrain 15. The detailed structure and dynamics of its ice shell and the timescales over which they evolve are critical for understanding both the fundamental geophysical processes and habitability of Europa 11. The thickness and thermophysical structure of this ice shell are poorly constrained, but models suggest it may be 20–30 km thick 4, 5, 6, 7, 8 with a layer of warm, convecting ice underlying a cold, rigid crust 9, 10. It's the incredible, advanced technology that is ALMA that allows these observations, increasing our understanding of the universe around us.Jupiter’s icy moon Europa harbors a global subsurface ocean beneath an outer ice shell 1, 2, 3. "Being able to observe from Earth enables the study of Io over a much longer term. "Humans have visited Io with robotic spacecraft that gave us highly detailed views, but those were fleeting observations," said Joe Pesce, a program director in NSF's Division of Astronomical Sciences. Based on the snapshots, they calculated that active volcanoes directly produce 30%-50% of Io's atmosphere. Thanks to ALMA's resolution and sensitivity, the astronomers could, for the first time, clearly see the plumes of sulfur dioxide and sulfur monoxide rise up from the volcanoes. We can therefore see exactly how much of the atmosphere is impacted by volcanic activity." "During that time, we can only see volcanically-sourced sulfur dioxide. "When Io passes into Jupiter's shadow and is out of direct sunlight, it is too cold for sulfur dioxide gas, and it condenses onto Io's surface," explained Statia Luszcz-Cook of Columbia University. To distinguish between the different processes that give rise to Io's atmosphere, a team of astronomers used ALMA to make snapshots of the moon when it passed in and out of Jupiter's shadow - an eclipse. "Is it volcanic activity, or gas that has sublimated from the icy surface when Io is in sunlight?" "However, it is not known which process drives the dynamics in Io's atmosphere," said Imke de Pater of the University of California, Berkeley. Previous research has shown that Io's atmosphere is dominated by sulfur dioxide gas, ultimately sourced from volcanic activity. It hosts more than 400 active volcanoes, spewing out sulfur gases that give Io its yellow-white-orange-red colors when the gases freeze out on its surface.Īlthough it is extremely thin - about a billion times thinner than Earth's atmosphere – Io's atmosphere can teach us about this exotic moon's volcanic activity and provide us a window into its interior and what is happening below its colorful crust. ![]() Io is the most volcanically active moon in our solar system. ![]() National Science Foundation-funded Atacama Large Millimeter/submillimeter Array, ALMA, show for the first time the direct effect of volcanic activity on the atmosphere of Jupiter's moon Io. ![]()
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