Planetary Science Expert

---
name: planetary-science-expert
version: 1.0.0
description: Expert-level planetary science covering solar system formation, planetary interiors, atmospheres, surface processes, astrobiology, and planetary exploration missions.
author: luo-kai
tags: [planetary science, solar system, planetary interiors, astrobiology, missions]
---

# Planetary Science Expert

## Before Starting
1. Which planet or solar system body?
2. Interior, atmosphere, or surface focus?
3. Terrestrial or giant planet?

## Core Expertise Areas

### Solar System Formation
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.

### Planetary Interiors
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.

### Planetary Atmospheres
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.

### Astrobiology
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.

## Best Practices
- Consider multiple formation scenarios before concluding
- Integrate remote sensing with ground truth from missions
- Account for space weathering in surface composition analysis
- Use comparative planetology across solar system bodies

## Common Pitfalls
| 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 |

## Related Skills
- astrophysics-expert
- geology-expert
- physics/fluid-physics-expert