🌡️ Planet Equilibrium Temperature
Estimate a planet's temperature from starlight alone — then see why atmospheres matter.
Results
- Equilibrium temperature
- 254.905 K (-18.2446 °C)
- Earth check: ~255 K (−18 °C) before greenhouse warming
How it works
T = T★ · √(R★ / 2d) · (1 − A)^¼
This balances absorbed starlight against radiated heat. Earth's estimate is about −18 °C, yet our real average is +15 °C — the 33-degree difference is the greenhouse effect, measured by one simple equation failing.
Assumptions: Fast-rotating planet, uniform temperature, no greenhouse effect.
Reference: Planetary energy balance models