Aurora — a real northern lights simulation

Aurora is a tiny physics simulation of three layered curtains of light dancing over a polar sky. Each curtain has a vertical ray structure, an undulating spine, and the classic aurora colour gradient — bright green oxygen emission in the middle band with a magenta fringe at the bottom edge, fading to violet at the top. They breathe and drift sideways on their own, like the real thing.

How to play

Drag anywhere on the sky and the curtains ripple at your cursor — vertical drag wobbles their spine, horizontal drag sends a wave of brightness travelling along them. Tap once to fire a substorm: a wide pulse of bright light that propagates outward through the curtains. The FLOW slider sets how fast the sky undulates, GLOW sets overall brightness. Pick one of four palettes — northern green/violet, magenta dawn, solar gold, or icy cyan. Drift toggles slow horizontal sliding. Calm stills everything, PNG saves the moment.

Why it's satisfying

Most people will never see a real aurora — Tromsø, Iceland, Yellowknife are far. Aurora gives you the closest thing a browser can: a sky that lives even when you do nothing, and that explodes into colour the second you touch it. Substorms feel like dropping a stone into still water, except the water is light.

About

Aurora is part of Alcy, thirty free contemplative micro-games in your browser. For more sky: Constellation, Snow, Fireflies.