SPH Models of the Moon-Forming Giant Impact
Contributed byScott Hull and Miki Nakajima, University of Rochester
The conventional theory for the origin of the Earth’s Moon is the giant impact hypothesis, which describes an oblique, low-velocity collision between the Earth and a Mars-sized planet, Theia (Canup & Asphaug, 2001). Within this framework, the Moon accretes from a debris disk that is produced by the impact. This model can reproduce the mass, dynamics, and low iron content of the Moon. A well-known weakness of the canonical giant impact hypothesis is that the remnants of Theia’s mantle dominate the disk, which contradicts the strong isotopic similarities between the Earth and Moon that suggest a common material origin if the Theia’s isotopic composition differed from the Earth.
Smoothed Particle Hydrodynamics (SPH) is the numerical method of choice for simulating high-energy astrophysical events such as the giant impact. SPH is a particle method in which ... [full article]