There was a time when all we knew were the nine planets (now eight) that revolve around our sun. Then we developed amazing space telescopes that can capture images outside our solar system. On March 21, the 5,000th exoplanet was confirmed. To celebrate this milestone, NASA put together a timeline on a 360° map, showing when each exoplanet was discovered.
As each exoplanet is discovered, a circle appears at its position in the sky. The size of the circle indicates the relative size of the planet's orbit and the color indicates which planet detection method was used to discover it. The music is created by playing a note for each newly discovered world. The pitch of the note indicates the relative orbital period of the planet. Planets that take a longer time to orbit their stars are heard as lower notes, while planets that orbit more quickly are heard as higher notes.