  The formation of life is an automatic stage in the consolidation of rocky or
"terrestrial" planets. The organic (=carbonaceous) matter, light elements,
gases, and water must "float" toward the surface and the heavier metals must
sink toward the center. Random processes in the molecular soup that fills
microfractures in unmelted crust eventually produce self-replicating
microtubules. In an appendix I suggest that some primordial crust remains
because there is not enough consolidation energy to melt the whole planet.
Energy is lost when iron planetesimals first partially melt and then coalesce
to form the molten iron planetary core. Stony planetesimals accrete onto the
surface of an already consolidated core.
