The True Shape of Io's Steeple Mountain

Summary

Additionally, the surrounding terrain in the artwork appears unusually flat, which is inconsistent with the curvature dictated by Io's small radius. The actual surface of Io would show more pronounced curvature.How we created the new lookWe used a new global map of Io compiled from the Juno mission's images by Gerald Eichstädt, Jason Perry and John Rogers.Applying it back to a sphere, we oriented the map to the sunlight, and treated the shadow as it was cast on a perfect sphere (though Io, like all celestial bodies, isn’t really a perfect sphere, the differences were negligible for the purpose of this reconstruction). Having a projection of the shadow and a top view of the mountain allowed the three-dimensional shape of the ridge to be reconstructed.The next step, to recreate the elevation profiles of the flatter parts of the mountain, was achieved by adjusting and detailing a rough 3D model in the reconstructed lighting conditions to achieve the pattern of light and shadow similar to those from the photograph of the object. This could, in a sense, be called manual photoclinometry.However, computational photoclinometry could produce more scientifically accurate results; this approach was used along with some artistic interpretation to imagine further details not visible in the original data. Close-ups of other Ionian mountains taken by the Galileo mission were used as a reference for details, along with attempts to understand the processes that resulted in such a structure.What energizes Io's volcanic activity?Io is extremely geologically active, and its relentless volcanic activity is primarily driven by tidal friction resulting from gravitational interactions with Jupiter. Io experiences continuous tidal deformation, because its orbit is slightly elliptical rather than perfectly circular. As the moon moves closer to and farther from Jupiter along its orbit, the varying gravitational force causes internal flexing, generating heat through friction.Although Jupiter’s...