Stage 1
Io
Hadean-like fire — a crust that never sits still
The most volcanic silicate world known. Almost no craters. Sulfur still paints the ground. The first visible rocky face in the sequence.
What missions and papers show
Voyager found volcanoes in 1979. Pele, Loki, and hundreds more have rewritten the surface in years to about a million years. Juno argues against a shallow global magma ocean; eruptions can still be fed from a mostly solid mantle.
How this site reads it
This site reads Io as the first rocky face of the living cycle: a silicate lid that does not last as landscape.
What would kill this stage
If Io’s fire and sulfur are fully explained as a finished moon heated by tides, with nothing left of a first crust, Stage 1 comes off the table.