Lunar Formation via Triple Phase Transition in the Differentiating Proto-Earth

Michel DEBAILLEUL 

Where does the Moon come from?

This question has no agreed answer.

This work proposes that the Moon was born from the Earth itself — not from a collision with a foreign body, but from the internal dynamics of a fully molten, rapidly rotating proto-Earth.

The starting point is a thermodynamic necessity: accretion energy exceeds the energy required to melt the entire silicate mantle by a factor of ≈155.

The Hadean proto-Earth was therefore a self-gravitating magma body in rapid rotation (Trot ≈ 3.5 h), unstabilised, whose axis wobbled chaotically within [40°, 70°] in its own co-rotating frame.

A single physical driver — the progressive segregation of iron and nickel toward the forming core — triggers three coupled transitions:

the structuring of a Coherent Magmatic Torus within the Hadean intertropical band, two to three episodic hypersonic ejections that build the Moon layer by layer, and the delayed onset of the terrestrial dynamo (≈350 Myr, no free parameter).

Each lunar layer is a frozen archive of the state of Hadean differentiation at the moment of its accretion.

This architecture is testable: 

the theory predicts one or more seismic interfaces between 200 and 530 km deep — where successive lunar layers, increasingly rich in iron towards the interior, produce a measurable echo — within range of Chang'e 7 (August 2026) and Artemis III (2028-2029). 

Mantle ejecta from the South Pole–Aitken basin are predicted to carry a geochemical signature — anomalously high Fe/Si — testable by Chang'e-6 sample analysis and Artemis III direct sampling.

This work introduces a complementary short-term geochemical test based on the South Pole–Aitken basin, together with two additional acknowledged limitations:

impact mixing in SPA ejecta (L9) and the current absence of any sample directly constraining the deep lunar mantle (L10). All hypotheses are ranked.

All limitations are acknowledged.

The theory stands or falls on its observational predictions.