Sympyrean is a generative audio sequencer which uses a stellar system you create to produce the music it makes. The motion of the planets and moons within the system, as well as their distance from the star determine what notes you hear and when.
The motion of the planets and moons within the application are based on Johannes Kepler's third law of planetary motion which states that the orbital period of an object squared is equal to the cube of its semi-major axis. In simplest terms, this means that the farther out a planet is from the star, the longer it takes to orbit. The Earth is fairly close to our own star, the sun, and so its orbital period is only one year, but a planet like Saturn which is much farther out has a much longer orbital period; nearly 30 years!
The app was inspired by a concept called Musica Universalis (also known as the music of the spheres) which dates all the way back to ancient Greece. The story begins with the greek mathematician Pyathagoras who apparently loved to play with strings. What he discovered was that if he stretched a string between two points and placed his finger on that string and plucked it, the pitch (or note) it produced was determined by the length of the segment he plucked. More importantly, he found the notes which sounded the clearest were at interval ratios between the length of the plucked segment and the total length of the string. This is, in fact, where we get the system of tuning used in music today. For instance, the interval of a perfect fifth has a ratio of 3:2. If we take the note E4 which has a frequency of about 659Hz, and divide it by the frequency of the note a perfect fifth below, A4 at 440Hz, we end up with about 1.5 which is three halves or, you guessed it: a ratio of 3:2.
Pythagoras also thought that there may be strings which extended out from the Earth (then thought to be the center of the universe) to the very edge of the celestial sphere that also created notes that in combination created the music of the spheres. Where a planet fell on the length of the larger string would determine the pitch of that planet. So in other words, how far away a planet was from the Earth determined its own unique voice in the choir of objects floating about in the night sky.
The idea was picked up by a number of other philosphers, mathetmaticians, scholars, and astronomers thorughout the ages including Plato, Ptolemy, Boethius, and Johannes Kepler. Kepler actually spent much of his life trying to describe the motion of the planets in musical terms. He is famously quoted as saying that the earth shifted from Mi to Fa. What he meant by this is the ratio of the maximum orbital velocity of the Earth to the velocity at any given point in its orbit shifted from a ratio of 5:4 (a major third) to a ratio of 4:3 (a perfect fourth).
Sympyrean is an honest attempt to create this system which fascinated the great minds throughout history, but also hopefully just something fun to play around with. In recreating the system as described by Kepler, some adjustements had to be made. Mostly those regarding scale, if I wanted to display everything at scale and still be able to show the entire system I'd need an enourmous screen! But also a few adjustments were made for the sake of musicality, and ease of use. If you like the application please share it with your friends, or drop me a line at email@example.com
The artwork for Sympyrean was done by bay area artist and graphic designer Kat Reyes. Sympyrean was completed as part of the Graduate Multimedia Program at California State University East Bay. Special thanks to Rafael Hernandez, Jon Jenkins, Kat Reyes, Daniel Price, and Ellias Fullmore.
The source material for the audio assets used in Sympyrean were created by NASA scientist and Kepler team co-investigator, Jon Jenkins, who used some of the photometric data obtained from the Kepler spacecraft to create audio representations of that data. Launched in 2009, Kepler is a photometer, in other words, it measures the brightness of stars. Readings are taken once every 30 minutes which measure the brightness of stars within its field of view. The sounds you hear in Sympyrean are the sounds of some of these stars.
So how do you get sound from a star? Stellar light curves! What is a stellar light curve? Well, there are certain types of stars which vary in brightness or luminosity over time. These are called variable stars. Some of these stars vary their brightness regular intervals in much the same way that sound waves do. Most of the stars which do this are a type called pulsating variable stars. Their particular type of pulsation is caused by a condition within the star such that the outward pressure from the fusion in its core is greater than the gravity pulling the mass of the star inward. When this condition is present the star expands outwardly, and what we observe is an increase in the brightness of that star. Once equilibrium is met between the pressure pushing outward and the gravity pulling inward, the mass pushing outward still has momentum, so the mass of the star actually continues to expand until it reaches a point such that the gravity of the star pulls it back in, restarting the cycle. This pulsation can be, in some cases, very much like a soundwave in the way in which it oscillates. Think of a string vibraring, it goes forward in then back crossing equilibrium each time. It so happens that if you speed the pulasation of these stars up many many times and translate it into audio data, you can hear what this pulsation sounds like!
Dr. Jenkins was kind enough to allow the use of these sonified light curves, they were not however sufficient to supply the amount of pitch material needed for this project. The creation of the sounds used mainly involved subtractive synthesis with the waveform of the star as the base, granular synthesis with the waveform of the star as the base, wavetable synthesis using a method wherein through differing segments of the waveform were shifted through over a very short period of time with an envelope equal to the note’s attack, or spectral modification of the waveform itself to isolate, hybridize, or blur the regions of the waveform to result in the desired pitch and timbre.
If you like the sounds in this application, be sure to check out the album featuring TED senior global fellow Meklit Hadero, and MCs: Gabriel Teodros, and Burntface "Earthbound" by Copperwire I co-produced with the group which also features Jon's sonifications.
So how does this thing make music? Fair question. Well, whenever a moon passes between a planet and a star. The note which belongs to that moon is sounded. The farther out a planet is the lower the pitches of moons. If you choose the planet with the farthest orbit it will play the very lowest notes, if you choose the planet with the closest orbit it will play the very highest notes. Each planet has five moons to choose from, the closer moons are higher in pitch, and the farther away moons are lower in pitch.
In addition to the moons, each star and planet you choose has a set of ambient sounds associated with it that vary based on the particular configuration you choose for your system. The app will do its best to read what you've created and "play along".
To begin, click on the button labeled "Create". This will bring up the menu of stars, to select a star simply click the one you want.
If you click the star you've created at any time, or on the minimap it will bring you to the planet creation menu.
Create a planet by clicking on the type you'd like to select.
Once you create a planet Sympyrean will automatically zoom you to that planet's location on the map.
If you click the planet, it will bring up the available moons to choose from for that planet.
Once you select a moon, you can select an orbit for that moon with the mouse and click over the orbit you'd like to select. The pitch you hear when mousing over an orbit is the pitch that moon will play while in orbit.
You can cancel out of a menu at any time by right clicking or by clicking the object you clicked to create the menu (the star or planet).
To the right you will see six buttons, use the + and - to zoom in and out.
Click the X and then click any any planet, moon, or star on the minimap or screen to destroy that object. Be careful though! If you destroy your star, it will destroy your entire system!
Click the i button and then click any object on the minimap or screen to view information about that object.
Click the pause button to stop all objects from orbiting and mute the sound.
Click the play button to resume playback.
Sympyrean is a fairly CPU heavy application If you're experiencing poor performance, try closing other open tabs in your browser or closing out some applications on your desktop.