🌐 Earth Biome Globe

The global-scope sim of this batch — the whole Earth at once, not one location. A simulated year starting real date 1999-01-01 drives the real sub-solar point (the Sun's true declination each day): the day/night terminator and each hemisphere's snow line are both real physics, not scripted.

Simulated day day 0 · Jan 1

What's real: Bake/Program.cs computes the Sun's real declination (Meeus solar position) for every day of the simulated year via OnlyCSharp.PhysicsAndAstronomy.Astronomy — that declination IS the sub-solar latitude (an exact spherical-astronomy identity, not an approximation). The globe's lighting uses that direction as a real light vector, so the terminator you see is the actual great-circle day/night line. The 5 biome bands are stylised from the real Köppen-Geiger climate groups (latitude thresholds = the real 23.44° axial tilt and 66.56° polar circle); the region→dominant-letter table and the snow-line model are our own simplifications layered on that real input — see the code comments for exactly which parts are sourced vs. synthesised. Small vegetation markers (real plant families: palms/cacti/oaks/pines/tundra moss) and drifting weather markers each keep a minimum great-circle separation so nothing overlaps on the sphere.