Articles About Message Construction

Celestial Music?

Article written by Dr. Douglas Vakoch
Originally published on December 22 2000 at Space.com

The suggestion of using music to communicate with intelligence beyond Earth has a long history. As early as the 17th century, the European literary genre of the imaginary voyage provided a context for exploring a variety of proposals for universal language schemes.

For example, the English clergyman Francis Godwin described a voyage to the Moon, in which the terrestrial adventurer encountered strange and exotic Lunarians who communicated through a musical language. The inspiration for this tonal language, however, was thoroughly terrestrial -- based on the Chinese language as described by Jesuit missionaries recently returned to Europe.

In the case of Godwins lunar "language," the musical system was simply a method for translating letters of the alphabet into particular musical notes. However, it did preview more truly universal language proposals of the next three centuries.

But would musicreally be comprehensible to intelligent beings who evolved independently of humans on other planets? Are the mathematical and acoustical foundations of terrestrial music sufficiently universal to provide a basis for interstellar communication?

The astronomer Sebastian von Hoerner provided one argument in favor of the possible universality of at least some aspects of music. He suggested that if extraterrestrial intelligence had indeed developed music, the form of this music might share certain features with terrestrial music.

Particularly interesting is his analysis of the number of notes in musical scales. Von Hoerner suggested that the fact that a piano has 12 black-and-white keys in an octave is not completely arbitrary. Rather, the use of a 12-tone scale in Western music is based on the nature for polyphonic music -- in which more than one note is played at the same time. By Von Hoerners analysis, there are only a handful of possibilities for workable polyphonic music.

Specifically, polyphonic music must meet two competing demands, which always requires a compromise. First, an octave needs to be divisible into equal parts to allow for modulations from one key to another. Second, the tones corresponding to these divisions should be of frequencies that have specific mathematical ratios to one another.

Any attempt to satisfy both of these conditions, however, requires some compromise. Equal intervals do not provide exactly harmonic tones. Thus, one must be content with relatively close matches that use only some of all possible harmonics. For example, classical Western music uses a 12-tone scale that allows for 5 harmonics.

But according to von Hoerner, a 12-tone scale does not exhaust the "good compromises" for polyphonic music. One might also use a 31-tone scale or a 5-tone scale.

The choice among these scales might provide a clue about the sensory functioning of the intelligence using these scales. Those beings with more sensitive auditory processing than humans might make use of the finer divisions of the 31-tone scale.

In contrast, extraterrestrials with less sensitive auditory systems may be more likely to use a mere 5 tones. While the choice between scales may not be dictated by biology (as suggested by the existence of 5-tone, 12-tone, and 31-tone scales among human cultures), sensory apparatus may sometimes restrict the range of a species musical scales.

It would seem fitting if the imaginary voyages of centuries past provided us with clues about the real messages we might some day receive from extraterrestrials -- beings sure to be even more strange and exotic than those imagined by the most creative science fiction writers of today.

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Celestial Music?