Mercury radar speckle dynamics

Current data reveal that Mercury is a dynamic system with a core which has not yet solidified completely and is at least partially decoupled from the mantle. Radar speckle displacement experiments have demonstrated that the accuracy in spin-dynamics determination for Earth-like planets can approach 10−5. The extended analysis of space–time correlation properties of radar echoes shows that the behavior of speckles does not prevent estimation of Mercury’s instantaneous spin-vector components to accuracy of a few parts in 107. This limit can be reached with more powerful radar facilities and leads to constraining the interior in more detail from effects of spin dynamics, e.g., from observation of the core–mantle interplay through high precision monitoring of the 88-day spin-variation of Mercury’s crust.