Andrea Centazzo’s show “Einstein’s Cosmic Messengers” is a true fusion of science and art. Centazzo, world-renowned composer, multimedia artist, and performer, crafted the unique blend of music and video to celebrate the work of astronomers and physicists throughout history and, ultimately, the ground-breaking LIGO project.
LIGO, or the Laser Interferometer Gravitation-Wave Observatory, represents a collaboration of scientists working to detect gravitational waves—measurable disturbances in the universe caused, for example, when two massive objects orbit one another. Einstein first predicted the existence of this phenomenon in the early 20th century. Now, researchers have the technology to prove their existence and learn more about the celestial objects, like black holes, massive enough to cause waves detectable on Earth.
Centazzo is bringing “Einstein’s Cosmic Messengers” to Evanston for one live musical and multimedia performance sponsored by Northwestern’s new Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) on the evening of March 13th at the Cahn Auditorium. Before the concert, CIERA director Vicky Kalogera will deliver a short public lecture about LIGO. We talked to Centazzo and Kalogera to learn more about the inspiration and science behind this unique musical experience.
Vicky, why is it important for the researchers at LIGO to study gravitational waves?
(VK) Waves produced by black holes are direct expressions of their strong gravitational pulls. Studying them allows us to learn much more about the nature of black holes, like their mass and spin, in ways that aren’t possible through other methods. (Read about the science of gravitational waves.)
This event certainly presents a unique opportunity for the public to learn more about them. Andrea, what originally inspired you to compose a piece about astrophysics?
(AC) I started doing multimedia shows about 15 years ago, when the technology was ripe. First was Mandala, inspired by the Buddhist universe. Later I became interested in big personalities, like Leonardo da Vinci, and composed Eternal Traveler, which explores his art and genius through music and images.
Then I met Michele Vallisneri, a physicist at NASA's Jet Propulsion Laboratory and part of the LIGO collaboration. As learned more about his work, I started thinking about Einstein, another big personality with iconic ideas. And it was Einstein who first considered the idea of gravitational waves.
So Michele and I approached others at the LIGO project and worked together to conceive a logical path for the piece. The show is not just about Einstein—it has multiple parts, starting from when people first looked into the sky, and the early astronomers, like Galileo, who followed.
As you mentioned, the program has five distinct pieces, beginning with the curiosity of early astronomers, to Einstein’s thought experiments about space, time and gravity, to the modern-day work of the LIGO detectors. How does the subject of each section influence the music?
(AC) I composed single musical pieces inspired by the elements of each section of the show. For example, in the Einstein section, the music is influenced by Middle Europe at the turn of the 19th century with samplings of that era’s music, like a Viennese waltz, and by sounds from his life and work, like trains and the ticking of a clock. The LIGO section is full of computer-generated sounds related to the instruments used for detection.
The final section (which explores the last moments of two black holes orbiting one another) incorporates actual sounds, or chirps, from the wave detectors at LIGO with the music. These chirps are produced at very high frequencies. Using computers, we can tune them to make their pitch compatible with music. They sound almost like a synthesizer. We can also change the duration of the sound, which is actually very, very fast, to be slower. At the end of the piece, one chirp lasts a full minute, creating tension for the finale.
Vicky, what do these “chirps” from the LIGO detectors represent?
(VK) Gravitational waves are oscillations caused by fast-moving masses. These oscillations are regular, and they happen with frequencies to which LIGO is sensitive.
Now, sounds are also comprised of waves, but of a different type. It just happens that the frequency range LIGO is probing in gravitational waves is roughly the same frequency range of sound waves to which the human ear is sensitive.
So what people have done is taken a gravitational wave signal and its frequency and converted it to a sound wave with the same frequency. The volume of the sound tracks how the gravitational wave amplitude changes. In this way, we can "hear" some of the gravitational wave signals LIGO is expected to detect.
The music is accompanied by a video of dramatic scenes, animations, and images. Andrea, how does this multimedia component enhance the experience for the audience?
(AC) Of course, the music itself could stand alone, and the audience could imagine what the music suggests in terms of image. But the mix of the two is even more expressive, because of the power of the images.
The music and images—fictional scene shots of the early astronomers and Einstein, beautiful animations of how the Hubble telescope captures images and of black holes creating gravitational waves—they support one another. The entire show produces double emotion for the audience.
Performing the show live on stage creates a third element. The music is never exactly the same. Playing live, you adapt to the mood of the night; it’s not a predictable interpretation.
Did you learn anything about science through putting this piece together that surprised you?
(AC) I recognized the same passion in my scientist collaborators for their work as I have for my art. There is a communion of intent for both science and art—we’re both searching for something perfect that might not exist.