In the great heliosphere of our solar system, solar wind can't really be called wind at all. Instead, solar wind is made up of currents of plasma, and in the vacuum of space, it creates no sound at all as it rushes and rustles by. Here on Earth, though, we can now hear the solar wind thanks to artist Helen White. Tethering them to a 16-year-old NASA spacecraft 1.5 million kilometers away, White's solar-wind chime uses electromagnets and suspended aluminum tubes to the otherworldly 'sound' of deep space audible for the first time.
White created the solar-wind chime around the theme of communicating and visualizing science during her residency at the Pervasive Media Studio in Bristol, U.K. "I've always been fascinated by nature and the unique sets of conditions that need to happen to trigger certain phenomena," White tells me. "Moments such as rainbows, the northern lights or a particularly beautiful sunset occur through the alignment of a very specific set of criteria. With the solar-wind chime, I saw an opportunity to explore the unique ways in which the sun and Earth interact that lead to the aurora. I wanted to find out if I could turn solar data into a more tangible and physical experience."
The solar-wind chime works by plucking data from NASA's Advanced Composition Explorer (ACE). A spacecraft currently orbiting at the Langrangian point between Earth and the Sun, ACE is the first man-made object to feel the gusts of solar wind as it spins off the Sun heading towards Earth. ACE measures this space weather with its on-board instrumentation, then sends a weather report back to Earth about once every minute. "Not bad for a 16-year-old spacecraft 1.5 million kilometers from Earth that I get to use for free," quips White.
Once the data has been downloaded, the solar-wind chime turns this data into sound. "Each chime has an electromagnet at the tip that resonates at the same frequency as the chime," explains White. "Instead of the struck note you would hear from traditional wind chimes, this generates a tone. The data is processed in such a way to as to trigger different tones depending upon the speed of the solar-wind." The chime plays very slowly, an ambient sound that evolves over hours and even days in coordination with the fluctuation of the sun.
Because there is no contact between the electromagnet and the chime itself, the experience of being in the same room as the solar-wind chime is quite magical, as an invisible force causes motionless chimes to sing the music of the spheres recorded a million miles away. The sound itself, though, is strangely familiar, bringing to mind the strange ambient sound of deep space commonly used in films like Stanley Kubrick's 2001: A Space Odyssey or Andrei Tarkovsky's Solaris.
According to White, this similarity to various sci-fi deep space soundtracks was not by design. In trying to decide what the solar-wind chime should sound like, she began to explore microtonal music, using intervals not traditionally found in the Western system of placing 12 equal intervals to every octave. This, she felt, gave the solar-wind chime an otherworldly feel. As a happy coincidence, White later learned that she was not the first person to have this idea: it turned out this was the same method of composition used by György Ligeti in his score for 2001.
While the sound the solar-wind chime makes cannot properly be said to be the sound of solar wind itself, the chime does have practical and scientific purpose. "There's been interest in the chimes from solar scientists, as sonifying the data might allow them to spot patterns they otherwise might not have detected," says White. "The chimes can also provide an early warning of any potential geomagnetic storms that are headed our way."
That could be useful indeed. The last major solar storm happened 150 years ago, and it's believed that if a geomagnetic storm of the same magnitude hit Earth today, it could cause billions of dollars worth of damages, and cause widespread electrical blackouts for weeks. If such a storm were to hit Earth, the hour's heads-up the solar-wind chime could give us might be useful, don't you think?
You can read more about Helen White's solar-wind chime here.