Physics / Astronomy / Earth
Blackbody radiation
Planck's curve live: slide the temperature, watch Wien's peak march and the Stefan-Boltzmann area grow, and see the body's true color.
What happens
One law paints the whole scene: Planck’s curve stretches over a spectrum drawn in its real hues, the golden marker rides the Wien peak as you heat the body, and the orb beside it glows in the color a real CIE integration of that spectrum produces - coal red at 2000 K, white near 6500 K, star blue past 12000. The side chart is log P against log T: a straight line of slope four, Stefan and Boltzmann in one glance. The candle, the lamp, the Sun and Sirius are one press away.
Try this
The small orb is the star in its own colour. Match it by eye, then by the number; Next star cycles from Betelgeuse to Spica. Overlay lays the star's spectrum under the live one - the Sun against Sirius.
Equations used in the module
Equations B(λ, T) = (2hc² / λ⁵) / (exp(hc / λkT) − 1) (Planck) λ_peak T = 2.898 mm·K (Wien) P = σ T⁴ A (Stefan–Boltzmann) stars: Betelgeuse 3500, Aldebaran 3900, Sun 5772, Procyon 6530, Vega 9600, Sirius 9940, Rigel 12100, Spica 25000 K; λ_max = b/T: Sun 502 nm, Sirius 292 nm (ultraviolet), Betelgeuse 828 nm (infrared); σT⁴: Sun 62.9 MW/m², Sirius 554 MW/m² the task: |T/T_star − 1| ≤ 6 %
