These movies are results of our giant impact simulations using the Smoothed Particle Hydrodynamics (SPH) method, which treats fluid as a collection of spherical particles. The code has been developed by Miki Nakajima and it is integrated with a special hardware called GRAPE.
1. Standard giant impact [Youtube]
This video is based on a numerical simulation based on the standard giant impact model (Hartmann & Davis 1975; Cameron & Ward 1976). A collision between a Mars-sized impactor and Earth formed a disk around the planet from which the Moon accreted. The color show the entropy of forsterite in J/K/kg.
2. Three different scenarios
(a) Standard model
(b) Fast-spinning Earth model
(c) Sub-Earths model
These movies correspond to three different models: (a) standard model, a Mars-sized impactor hits Earth (Hartmann & Davis, 1975; Cameron & Ward, 1976), (b) fast-spinning Earth: a small impactor hits the rapidly rotating Earth (Cuk & Stewawrt 2012), (c) sub-Earth: two half-Earth sized objects collide. The colors represent the origins of materials (green: Earth mantle, yellow: impactor mantle, grey: Earth core, and white: impactor core).