The Journal of Geophysical Research: Space Physics study (peer-reviewed, not preprint) deploys JWST to map Saturn's northern auroral zone via continuous infrared H3+ emission over one full planetary rotation. This yields temperature and ion-density maps with ~5 °C precision, an order-of-magnitude gain over Cassini-era uncertainties of ~50 °C. The data confirm a closed electrodynamic cycle first modeled in 2010s MHD simulations but never spatially verified: precipitating electrons heat the upper atmosphere at precise magnetic footprints, driving equatorward winds that induce field-aligned currents which in turn sustain the aurora. Earlier Cassini radio measurements (2004–2017) had reported apparent 1 % changes in rotation period; Stallard’s 2021 analysis already attributed these to wind-modulated currents, yet lacked the heating source. JWST supplies that source at the exact latitudes predicted by the decade-old models. The single-day northern-hemisphere dataset, while unprecedented in spatial resolution, cannot yet address seasonal variability or southern symmetry, limiting extrapolation to full-planet behavior. Critically, the same auroral wind-current feedback operates on rapidly rotating gas giants regardless of formation pathway; applied to hot Jupiters, it implies that transmission spectroscopy retrievals of rotation periods may be systematically biased by upper-atmosphere electrodynamics rather than reflecting bulk interior spin—an effect absent from most current exoplanet atmosphere codes. Thus the Saturn result supplies a missing physical prior for interpreting phase-curve and Doppler wind data from JWST and future Ariel observations of extrasolar giants.