The Untempered Cosmos by R. Andrew Lee

An app that turns the night sky above you into music:

"The Untempered Cosmos is a piece of generative music that uses the sky above you as its 'score.' When you load the page, it asks for your location, looks up which named astronomical objects are above your horizon at that moment, and assigns each one a sine tone. The brighter the object, the louder. The higher in the sky, the more present. Each tone is placed in the space around you to match where its object is in the sky, so a star low in the east comes from your right and a star overhead comes from above. As the Earth turns, stars rise and set, and the chord changes with them.

There is no playback in the usual sense. Nothing is recorded, nothing repeats. The piece is a real-time rendering of the sky you happen to be standing under. Two people listening at the same instant from different cities will hear different music. The same listener returning at midnight will hear something different from what they heard at dusk.

Daylight silences almost everything. The Sun overwhelms the visible sky, and the piece honors that by fading the stars out as morning arrives. Only the Moon and the brightest planets stay audible in daytime, and only when they are far enough from the Sun to be visible against it. By night, the full chord returns.

What you end up with is a piece that is always playing somewhere on Earth and never playing the same way twice. It is also, in a small way, a way to learn the sky."