Overview
- The peer-reviewed study by researchers at the Southwest Research Institute and the University of Arizona, published Friday, used smoothed particle hydrodynamics with temperature-dependent material strength to model the Earth–Theia collision.
- When both bodies were hot and mechanically weak the simulations produced an almost intact Moon within about five hours instead of a slow assembly from orbiting debris.
- When the colliding worlds were cooler and stronger the models destroyed Theia and created a broad protolunar debris disk that would assemble the Moon over a much longer time.
- The work is a methodological advance because previous giant-impact models treated proto-Earth and Theia as fluids and ignored rock strength, and the SPH code used here was developed at the University of Arizona and the University of Bern.
- The simulations link impact temperature to possible volatile and structural signatures on the Moon but do not solve why Earth and the Moon share such similar compositions, so authors call for more simulations and geochemical tests of lunar samples to evaluate which pathway occurred.