Mutual Gravitational Capture as a Mechanism for Planetary Growth: An Alternative Hypothesis

This study proposes a new hypothesis for the rapid growth of rocky planets through successive mutual gravitational capture events followed by planetary fusion. The model suggests that gravitational interactions between differentiated bodies with small mass differences can lead to collisions at velocities below the threshold required for full disruption, allowing fusion. The resulting planetary body, with mantle redistribution, internal reorganization, and potential orbital changes, would occupy an intermediate orbit. The model predicts the formation of geological structures such as mountain belts, partial reassembly of the inner core, and mantle heterogeneities. Some of these signatures may be associated with the South Atlantic Magnetic Anomaly, mantle transition zones, subducted crust, and variations in biodiversity. During the process, part of the crust of the smaller body may temporarily form a supercontinent, which subsequently fragments into continental blocks. The hypothesis provides an alternative to current paradigms and generates testable predictions for future investigations on the geodynamic, magnetic, and orbital evolution of Earth and other bodies in the Solar System.