Wet comet model: Rosetta redux

The wet-comet model (WCM) of the structure and composition of comets was developed in 2005 to replace the “dirty-snowball” model (DSM) of Fred Whipple, because the first comet flybys of P/Halley “armada” revealed a very different landscape. Subsequent flybys of P/Borrelly, P/Wild-2, P/Hartley, P/Tempel-1 have confirmed and refined the model, so that we confidently predicted that the Rosetta mission would encounter a prolate, tumbling, concrete-encrusted, black comet: P/Churyumov-Gerasimenko. Unfortunately, the Philae lander team was preparing for a DSM and the anchors bounced off the concrete surface, but the orbiter has returned spec- tacular pictures of every crevice, which confirm and extend the WCM yet a sixth time. We report of what we predicted, what was observed, and several unexpected results from the ROSETTA mission.