  We found evidence for critical internal heat values during significant
geophysical transitions in the inner solar system planetary bodies in
association with volcanism. From a simple rocky planet thermal evolution model,
we could infer critical surface heat flux values during peak phases (~1.2 W/m2)
and cessation phases (~ 0.092 W/m2) of major volcanism in Earth, Moon, Mars,
Venus and Mercury. The above phases of volcanism are accompanied by significant
geophysical transitions like growth and decay of global planetary magnetic
fields which is likely to be related to systematic changes in core-mantle
boundary heat flux values. The above results suggest the that planets are
possibly self-organised physical systems with strong core-mantle-crust coupling
. The present study will have implications on the search for habitable
extrasolar planets.
