Our Milky Way galaxy, which is at least 100,000 light-years across, completes a rotation in a leisurely 225 to 250 million years.
This galactic year has been translated into music by astronomer Mark Heyer of the University of Massachusetts Amherst. Based on 20 years of radio telescope data, he figured out an algorithm that translates the movements of gases into musical notes, allowing us to “hear” what the Milky Way sounds like as it rotates. (A full explanation can be found here.)
Turns out our galaxy sounds like jazz.