Atmospheric Optics (2D)

This 2D companion to the 3D Atmospheric Optics simulator isolates the two phenomena that belong to the atmosphere itself rather than to raindrops: Rayleigh scattering, which paints the sky blue and sunsets red through a real 1/λ⁴ scattering law and Beer-Lambert extinction along an increasing air-mass path, and the 22°/46° ice-crystal halo, produced by minimum-deviation refraction through hexagonal ice prisms using ice's real refractive index. Drag the sun toward the horizon to watch the physics play out live, or switch scenes to see why halos ring the sun at an exact angle instead of spreading like a rainbow.