Expert-level planetary science covering solar system formation, planetary interiors, atmospheres, surface processes, astrobiology, and planetary exploration missions.
Nebular hypothesis: solar system formed from rotating disk of gas and dust. Planetesimal accretion: dust grains to pebbles to planetesimals to planets. Giant planet formation: core accretion or disk instability models. Late heavy bombardment: intense impact period 4.1 to 3.8 billion years ago. Migration: giant planets migrated inward or outward after formation.
Differentiation: dense materials sink to core, lighter to mantle and crust. Earth structure: iron core, silicate mantle, thin crust. Moment of inertia factor: constrains interior density distribution. Magnetic field: generated by convection in liquid metallic cores via dynamo theory. Seismology: Mars InSight data revealed Martian interior structure.
Escape velocity and atmosphere retention: lighter molecules escape more easily. Venus: thick CO2 atmosphere, runaway greenhouse, 465 C surface temperature. Mars: thin CO2 atmosphere, dust storms, polar ice caps of CO2 and water ice. Giant planets: H2 and He dominated, Jupiter Great Red Spot, Saturn rings. Titan: nitrogen atmosphere with methane cycle and organic chemistry.
Habitable zone: region around star where liquid water can exist on surface. Mars: subsurface liquid water possible, ancient river channels confirmed. Europa: subsurface ocean under ice shell, potential for life. Enceladus: active geysers of water, ocean confirmed by Cassini. Biosignatures: chemical or physical signs of life detectable remotely.
| Pitfall | Fix |
|---|---|
| Earth-centric view of habitability | Other solvents and energy sources are possible |
| Ignoring impact history | Craters provide chronological information |
| Confusing surface age with formation age | Resurfacing can reset crater counts |
| Assuming similar processes on all planets | Conditions vary enormously across solar system |