Selected Cosmos is a sonification of the sequence of nucleobase pairs (as reported by the Human Genome Project at ncbi.nlm.nih.gov/projects/genome/assembly/grc/) of human DNA (i.e., deoxyribonucleic acid, the molecule that bears the information that guides the growth of nearly all living organisms).
This excerpt presents a portion of chromosome number 22, which is one of the shortest human chromosomes, with only approximately 49 million base pairs. A complete sonification of chromosome 22 here would require just over 88 days (and a sonification of all 23 pairs of the human chromosome would require nearly 15 years to complete at the rate the information is presented in this piece).
In the double-helical structure of a molecule of DNA, each member of the base pair attaches to a spiral backbone of sugar (deoxyribose) and phosphate, and the chemical structure on each spiral is arranged in the opposite direction to that of the other spiral. To sonify this molecular sense of direction, the music includes a layer of two tones that are filtered in an overlapping way, in the manner of Shepard tones (en.wikipedia.org/wiki/Shepard_tone), to suggest that each direction extends possibly to infinity.
The pitch of these Shepard-filtered tones is 54 octaves above the sound emitted by an active galactic nucleus in the Perseus Cluster (3.333 * 10^(-15) hz). Thus the piece encompasses structures at both the micro and macro levels. Occasionally sounding on this same pitch are sampled or synthetic voices chanting the Latin word “Omnium” (all). In the video portion of this work these sounds are accompanied by slowly morphing images of the cosmic background radiation, as imaged by the Cosmic Background Explorer (COBE), the Wilkinson Microwave Anisotropy Probe (WMAP), and the Planck orbiting observatory.