The piece attempts to aurally model the solar system as accurately as possible whilst making a piece of music of CD length.
Method
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Orbital data from Wikipedia was taken for each of the (then) nine planets of the solar system.
The orbital period was halved repeatedly so that, according to the octave principle in acoustics, frequencies could be derived which would be octave-equivalent to the planetary orbits but audible to humans.
For more detailed information regarding octave equivalence modelling, click here.
Implementation
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Each planet yielded six audible frequencies (all octave-equivalent) and, at longer lengths (fewer halvings) six musically meaningful durations.
Rather than produce a static model, which would just be a chord, I decided to use each of the frequencies and durations in turn for each planet.
This means that for a given 'planet' in this model, the melodic form is broadly a semibreve in the bass followed by a minim in the tenor, a crotchet in the alto and so on, with each successive note being an octave higher and half the duration of the previous one.
All the planets are presented simultaneously. This means that the various melodies are layered to produce non-overlapping patterns, always slightly different.
I have included the raw materials so that you can compile your own version of this piece (you may be vehemently opposed to Pluto, or have a yearning for 2003 UB313 or Ceres!). The raw data can be used in a number of ways.
To hear the 160kbps MP3 version of the default published album version, click HERE.
The files labelled DATA contain tables of durations and frequencies. The larger Excel-2000 workbook contains a lot of the workings out, preliminary thoughts, etc. including erroneous early approaches which succumbed to the fallacy of turning numbers into frequencies, ie. 400 becomes 400hz. This is entirely wrong, as 400hz is 1/400 seconds, not 400 seconds (obviously when you think about it!!), but on paper it's an easy trap to fall into. Another early fallacy was scaling the figures numerically. Frequencies behave logarithmically, with octaves sounding the same at 2:1 ratios. Therefore arbitrary division/multiplication destroys the flavour of the pitches and completely undermines any link between the original figures and the end-product. The best approach, in the end, was dividing ONLY by powers of 2 (ie. octave-shifting ONLY).
There is a support page for this "Octave Equivalence Tool" here (http://homepages.tesco.net/gregskius/oet.html) but the same distributed version is always kept updated here on the Internet Archive. The tool calculates the equivalent frequency of light as well as audible sound, so will be of interest to people with an interest in synaesthesia and related subjects.
For maximum compatibility, here's the frequency and duration data in plain text format (comma-delimited):
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Reviewer:Sevish -
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July 8, 2010 Subject:
New harmonies
This piece is incredibly interesting... To use the orbits of the planets and convert that into pitches for use in music... Very cool.
I am very glad the author has decided to include the frequencies (Hz) of each planet. I have entered these frequencies into my tunesmithing software (Scala) and have been improvising over this ambient work. It's something a lot more people should try - I'm thinking about composing some music with this planetary tuning myself. (Though I omitted Pluto).
You SHOULD listen to this if you want to hear something very different. :)
Reviewer:marylandgreenpower -
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October 15, 2009 Subject:
Alternate Music
Update: I just read your consideration of asteroids. Brings to mind, which objects are appropriate due to their size?
About your question concerning moons: Yes, they do not orbit the Sun per se, but piggy back with their host planets. Thus, would it be appropriate to include their tones as an amplitude modulation of their host planet's frequency? E.g., Our Moon's period superimposed on Earth's 265 day period?
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