According to the canonical model, the proto-Earth was hit by a Mars-sized object approximately 4.5 billion years ago. The movie below shows entropy of the mantle (the extent of shock heating) in the red-yellow colors and iron core in grey. We developed a smoothed particle hydrodynamics (SPH) code from the ground up where a fluid is expressed as a collection of spherical particles.

Feel free to download the movie from here: [canonical - entropy] 

Please cite Nakajima and Stevenson (2014, 2015).

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A number of impact models have been suggested, including (1) canonical model, where the proto-Earth is hit by a Mars-sized impactor, (2) fast-spinning Earth model, where the rapidly rotating proto-Earth is hit by a small impactor, (3) half-Earths model, where two half-Earth objects collide, and (4) multiple impact model, where the Moon formed out of multiple small impacts.

We perform numerical simulations to represent (1)-(3) models as below. The green and yellow represent the mantle of the proto-Earth and impactor, whereas grey and white represent their iron cores, respectively.

Feel free to download the movie from here:

[canonical - material]  [fast-spinning Earth - material]  [half-Earths - material

Please cite Nakajima and Stevenson (2014, 2015).