An interactive globe of the most volcanically active body in the Solar System, textured with the USGS Galileo SSI + Voyager ISS controlled merged-colour mosaic. All 260 IAU-adopted names are selectable — 170 paterae, the montes, the flow fields and the great albedo regions; the research feed is retrieved at run time.
The sphere is rendered in Three.js at Io's volumetric mean radius, 1821.49 km (IAU 2015), scaled to scene units. The base layer is the USGS controlled merged-colour global mosaic at 1 km/px, in which Galileo SSI colour ratios are merged with the higher-resolution monochrome Galileo and Voyager frames; the yellows, whites and reds are sulphur and sulphur-dioxide frosts, the dark patches are silicate lavas at their vents. Relief is offered but has no measured source: no controlled global digital elevation model of Io has been published, so with relief enabled the page derives a bump map from mosaic luminance, which encodes illumination and albedo rather than height. Should a DEM be added to Data/worlds/io/layers/ the displacement path activates unchanged. Textures are read from Data/worlds/io/.
Named features are the complete IAU set drawn from the USGS Gazetteer of Planetary Nomenclature via Data/worlds/io/features.json: 260 records, of which 170 are paterae — the flat-floored volcanic depressions that hold most of Io's eruptive activity — together with the montes, the fluctūs flow fields, the mensae and plana, and the ten great albedo regiones. A centre point is an official coordinate; it does not imply a mapped outline, a plume, or a current activity state. The research panel queries body_server.py at /api/io/latest for current Io literature (NASA ADS, with OpenAlex and arXiv as fallbacks); a per-feature endpoint returns recent papers on the selected feature. Absent a server, the seed research.json and ADS search links are substituted. Engine, server and schema are shared with the Mercury, Venus and Moon globes.
Markers use the east-positive convention of the IAU, converted on ingest from the Gazetteer's positive-west publication. The longitude registration of the mosaic was measured rather than assumed: the 156 equatorial paterae in the catalogue were sampled against the four possible mirror-and-offset combinations of the texture, and only one places them systematically dark — a mean of 94.8 DN against a 131.7 DN band mean, with 88 % of individual paterae below it. That combination is the same as Mercury's, so lonOffsetDeg is zero and the image left edge is 180°E. Loki Patera (13.0°N, 51.2°E) and Pele (18.7°S, 104.7°E) are the visual registration checks.
Io is highlighted in cyan on a live map of the uniquely-named solar-system bodies — planets, dwarf planets, named asteroids and comets — with the interstellar objects and escaping spacecraft, each at its current position and linked to its source.
body_server.py