Venus surface radiothermal emission as observed by Magellan

Radiothermal emission results obtained by the Magellan spacecraft during its first 8-month cycle of data taking, corresponding to one full rotation of Venus, are reported. The new Magellan data confirm the existence of regions with extremely low values of radiothermal emission. Possible mechanisms to explain the anomalous phenomena are an interaction with a single interface between the atmosphere and a high-dielectric permittivity medium versus volume scattering from the interior of a low-loss medium. The discrimination between these mechanisms requires careful observation of the polarized state of the radiothermal emission and that of the radar scattering.