Sort Sol

Sort Sol — "black sun" — is one of northern Europe's great natural spectacles: tens of thousands of starlings gathering over the Danish Wadden Sea each spring and autumn, dancing across the evening sky in rolling black bands. This app simulates it. There is no video in here — the flock is computed while you watch, thirty times a second, bird by bird. IN YOUR OWN SKY Point the phone up, tap, and the flock is standing in your own view. The sun's position is worked out from the time and the place you're in, so the light on the wings matches the evening you're actually standing in. You can also watch it without the camera, against the app's own dusk sky. NO BIRD IS STEERING Each bird watches its seven nearest neighbours and matches them. That's all. The bands, the waves, the sharp edge and the sudden turns emerge on their own once tens of thousands do it at once — exactly as they do over…