Monochromatica: You refer to galaxies as your co-performers. Please explain. How is it that a galaxy emits a sound? How do you record that sound?

We think of the universe as a cold and silent place but it calls to us everyday in a voice that seems to be without timbre and so deeply silent that we cannot hear its song. Yet the voice of the universe is around us every day, in an everlasting cosmic embrace. The universe throbs with cosmic dust, and beats with atoms and molecules. It is everlasting, but fleeting. It is what we don't see that can matter most. The cosmic radiations are precious data that are impossible to repeat. They come from the past and soar by us to a distant future. These traces of the primordial universe are received as waves, vibrations. Radio waves, like gamma, X-rays and others are not a part of the visible universe. Their domain is the radio universe. Seeing without sight. Optical astronomy started when man first looked up at the sky. Since ancient times we have investigated life and science visually, with drawings, charts, and pictures of every kind. Now we measure position, brightness, and we take photos of the night sky. When we receive electromagnetic emission from celestial objects we create graphs and maps. Man "sees" and "watches" science, "observing" the universe. We have always demanded an image. But, not very long ago, in about 1933, faint radio noises were found coming from the center of our galaxy. This science grew up and was called radio astronomy. Today we detect cosmic radio waves from many unusual celestial objects such as pulsars, quasars and the "so called" radio-galaxies. The radiation that washes over us every second speaks of catastrophic phenomena in turbulent galaxies far away in both space and time, perhaps reaching back to the first instant of universal life. We are poor explorers if we do not consider listening to the pulsation of the cosmos. Through Acoustic Astronomy we can marry the knowledge of the visible universe with the sonorous universe to form a greater whole. Do we receive a musical signal from the stars? Not exactly. Every celestial object emits radiation based upon its unique nature. If these signals are interpreted into sound rather than graphs, every star in the sonorous universe can be recognized based upon its special sound. As part of my doctoral research in Physics, working at the University of California, San Diego, Center for Music Experiment, and at the University of Milan, I developed a way to transform galactic radiation into sound, using a computer music system. The basic process is to shift the very high frequency vibrations down to the human hearing range, to create for the first time a Sonorous Universe.

"Acoustic Astronomy" is the first experiment that allows us to transform radiation from deep space into something that we recognize as sound. It started by observing the close analogy between galactic radiation and musical notes -- both of which are decoded by intensity and frequency (or wavelength). The intensity represents how strong the signal is. A sound, for example grows louder with greater intensity, and softens with less intensity. Radiation waves striking Earth also occur in varying degrees of intensity. Frequency represents the cycles per second, or in simple terms, how many times the radiation goes back and forth in one second. This is measured in Hertz. One cycle-per-second equals 1 Hertz, 100 cycles equaling 100 Hertz and so on. In music, our familiar "A", that we tune all instruments to, vibrates at 440 Hertz. The human voice range is from 27 to 4,186 hertz. The voices of the galaxy, however, are incredibly high. They range from one billion to one-thousand-billion Hertz. To have galactic radiation fall into the human hearing range, a mathematical reduction of the high frequency waves is required. The first experimental "subject" was a galaxy invisible to our eyes that hides in the darkness, far away in the direction of Coma Berenices, between Virgo and Leo, under the handle of the Big Dipper. Galaxies we cannot see rarely earn beautiful names, and this one is known simply as radio galaxy UGC 6697. After it had traveled 180 million light years, the radiation from UGC 6697 was collected in huge radio and optical telescopes by staffs of researchers and astrophysicists. These radiations were turned into a radio photograph of the galaxy, forming an image. I decided to try to play them - to represent the same data in the acoustic domain. Natural radio waves from stars and galaxies are produced by the chaotic motion of high energy electrons: countless "particle collisions and accelerations" not synchronized with each other. Every kind of celestial radiation can be represented as a stream of numbers. To convert the radiations' frequencies and intensities to audible form, I needed a special computer sound synthesis program called "cmusic", which I used to interpret the signal in terms of sound. After a variety of processing, this signal can be sent to a digital-to-analog converter and played through conventional loudspeakers or recorded onto digital tape or CD, to bring you the sound of UGC 6697 from 180 million light years away.