Giant Impact Scenarios: Earth-Moon System Formation

These flashcards cover key vocabulary related to giant impact scenarios in Earth's history, specifically focusing on the Earth-Moon system formation and its implications.

GIANT IMPACT SCENARIOS

Impact origin studies aiming to identify collisional events that explain the Earth-Moon system's properties.

Angular Momentum (LEM)

Current angular momentum of the Earth-Moon system, approximately 3.5 x 10^41 g cm² s^-1.

Roche Limit

The distance within which a given astronomical body will disintegrate due to a tidal force exceeding the body's own gravitational self-attraction.

Ejecta

Material ejected during a collision, which can form disks around planets after impacts.

Smoothing Particle Hydrodynamics (SPH)

A computational method used for simulating the dynamics of fluids and gaseous processes, often applied to impacts.

Canonical Impact

A type of impact involving a roughly Mars-mass impactor colliding with Earth at low velocity, producing an iron-depleted Moon.

Hit-and-Run Impact

Impact scenarios that involve higher velocities and less oblique angles, resulting in disks with more target material.

Fast-Spinning Earth Impact

Impacts into a rapidly rotating Earth that result in substantial angular momentum and must create a corresponding disk.

Half-Earth Impact

A scenario where two objects, each about half the mass of Earth, collide to produce a disk with equal silicate compositions.

Equilibration

The process that may erasure distinctive compositional signatures of the impactor in the post-impact disk.

Post-Impact Evolution

The complex evolution of the planet and its orbiting material following a significant impact event.

Hf-W System

A geochemical system relevant to the early Earth, characterized by isotopic anomalies indicating mantle heterogeneity.

Mantle Heterogeneity

Variations and differences in the composition of Earth's mantle, which may persist due to impact events.

Multiple Impacts

Model suggesting that Earth's Moon may have formed from a sequence of medium to large collisions.