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Instability, mixing and fragmentation in planetary collisions
The Earth formed by high-energy collisions between planetary embryos. I will present laboratory experiments on the fluid dynamics of these collisions. I will show that the impact of a liquid volume onto a liquid pool reproduces the cratering observed in numerical simulations and at the surface of planets. Unlike simulations, experiments produce turbulent mixing. From our findings, we infer the drop size and the degree of mixing within the forming Earth. These parameters controlled the composition of the Earth’s interior.