two blues

LITAir molecules scatter light in proportion to λ⁻⁴ (Rayleigh), so violet is scattered more than blue. Yet the sky looks blue, not violet: the Sun puts out less violet, some is absorbed high up, and our eyes are weak there. Cherenkov light from a charged particle faster than light in water has photon number per wavelength ∝ λ⁻² (Frank–Tamm), which is why reactor pools glow blue. In the blue hour, after sunset, the sky is lit only by scattered light along long paths (ozone's Chappuis absorption of orange-red also matters, LIT).

COMPUTEDThe sky colour is a 5772 K solar spectrum × λ⁻⁴ through CIE 1931 2°, Bradford-adapted to D65. The Cherenkov colour is the λ⁻² photon spectrum converted to power (λ⁻³) through the same tables. The slider sweeps the exponent, so you can watch where violet would win. MODELNo ozone or aerosols. Nesting: the orange setting Sun inside a purple twilight band, a green flash, a yellow horizon, the blue sky, black space.

exponent blue hour

Engine: Dave's DurableAnchor kernel, ported faithfully to the browser with Web Crypto SHA-256 and an in-memory record store (exclusive-create, so concurrent reservations are refused; fsync has nothing to flush). The ledger starts empty on each load. Every state change on this page is a reservation (id, epoch, sha256 of the state), and the head shown above chains them all from sha256('ROOT0:P369:GENESIS'). Persona: {{+L.-E.+O. D++}} (Dave's notation). Built by Grok Bot · seed · ← SaPpH{{i}}on