# Physics Astro

> Model astrophysical systems — stellar structure, orbital dynamics, cosmology, gravitational waves — with physical scales, order-of-magnitude estimates, and scaling laws.

- Skill: `quantumquirkxyz/physics-astro` (Agent Skill)
- Install (CLI): `npx skillmds@latest add quantumquirkxyz/physics-astro`
- Raw SKILL.md: https://api.skillmd.com/api/skills/quantumquirkxyz/physics-astro/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Web & Frontend
- Author: quantumquirkxyz (https://skillmd.com/u/quantumquirkxyz)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/quantumquirkxyz/physics-astro

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## Contract

- **Input:** problem description and inputs defined by the skill body.
- **Output:** Markdown artifact with completed process steps.
- **Side effects:** none.
- **Dependencies:** none.
- **Stop condition:** all process steps executed; artifact saved with required sections.
- **Risk:** low.
- **Boundary:** produces reasoning artifact only; no system changes.


# Astrophysics Modeling

Model an **astrophysical system** — stellar, galactic, cosmological — with physical scales, order-of-magnitude estimates, and known scaling laws.

## When to use

- A stellar, planetary, galactic, or cosmological problem needs a quantitative model.
- Order-of-magnitude estimates for astrophysical phenomena.
- Connecting observations to physical theory.

## Process

1. Identify the astrophysical regime — stellar (fusion, HR diagram, mass-radius), orbital (Kepler's laws, n-body), galactic (dynamics, spiral structure), cosmological (FLRW, CMB, dark matter).
2. State physical scales — distances (AU, parsec, Mpc), masses (M☉), times (Myr, Gyr), temperatures.
3. Choose the governing physics — gravity (Newton/Einstein), thermodynamics, nuclear physics, radiation transport.
4. Apply scaling laws — Virial theorem, Jeans equations, mass-luminosity relation, Kepler's 3rd, Chandrasekhar limit, Schwarzschild radius.
5. Estimate numerically — order-of-magnitude before exact calculation; use the scaling to catch errors.
6. Check against observations — known values for comparable objects (e.g. Sun, Jupiter, Milky Way mass).
7. Deliver — artifact: regime, scales, governing physics, scaling laws applied, numerical estimate, observational check.