watch the earth turn · a foucault pendulum in real time · 8 hours for sleep

a pendulum 67 meters long, swinging in a dark stone hall, in real time for 8 hours. nothing pushes it sideways, yet its swing slowly turns: what turns is the floor, carried around by the earth. at the latitude of paris it turns 11.3° every hour. by the end, the pin under the bob has drawn a quarter of a circle in the sand. what you see a brass bob on a 67 m wire, like the one léon foucault hung in the panthéon in paris in 1851. one swing, there and back, takes about 16 seconds. it is started the traditional way: tied back with a cotton thread, and the thread burned over a candle, so nothing pushes it sideways. a pin under the bob scrapes the sand: every line in the fan is a moment of tonight. the small dial in the corner shows how far the floor has turned. what you hear the music is tuned to the earth. one turn of the earth (23 h 56 min) and one turn of the pendulum at paris (31.8 h), raised 24 octaves, give 194.7 hz and 146.6 hz: almost a perfect fourth, because at this latitude the pendulum turns at about 3/4 of the earth's speed. every degree the floor turns (about every 5 minutes) a low brass bell rings and the chord changes. each time the bob passes the middle you hear the air and the sand move, from where you see it: at first from left to right, by morning toward you and away. how it's made nothing here is filmed or stock. the hall, the light, the sand and the bob are computed from scratch: the bob follows the real equations of a foucault pendulum on the rotating earth (latitude 48.85° n), the fan in the sand is exactly where the pin has been, and the sound is synthesized in time with the picture. 0:00 the thread burns 0:25 the first line in the sand 1:00:00 11° 2:00:00 23° 3:00:00 34° 4:00:00 45° 5:00:00 57° 6:00:00 68° 7:00:00 79° sources: wikipedia "foucault pendulum" · observatoire de paris (pendulum day: 31 h 47 min at paris) · iers (earth's rotation). generated from scratch: sound and visuals. #foucaultpendulum #sleep #physics #realtime #ambientmachine