Geology & Geophysics GeoFIZZ

Dropping the Beat with Some Geoscience Data

Listen to the music of the ice, the turning of the planets, the ringing of rings, the rockin’ of quakes, and the mournful tones of global warming.

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How do you understand glacial settling, orbiting planets, and climate change? Charts, tables, graphs, and maps are all well and good, but have you tried using your ears?

It turns out that the hills—and glaciers, earthquakes, and even exoplanets—are indeed alive with the sound of music. About 2 decades ago, scientists began creating for public consumption musical versions of sunspots, solar flares, and acoustic waves traveling through the Sun. As years passed, many geoscience data sets similarly have been turned into auditory scientific creations with an innovative use of microphones, numerical simulators, synthesizers, or music software. These sonified data allow listeners to get a different take on some familiar topics.

Have a listen to some of these latest geomusical creations…just be sure to have your headphones in!

 

Ice, Ice, Baby

When public attention turns to glaciers, it’s all about the melting. But what do the glaciers sound like as they slowly retreat? Matthew Burtner wanted to find out.

Burtner is an ecoacoustic specialist and professor of composition and computer technologies at the University of Virginia in Charlottesville, and he’s interested in capturing the sounds of our changing planet. Some of his music was featured by the U.S. Department of State’s Conference on Global Leadership in the Arctic: Cooperation, Innovation, Engagement and Resilience (GLACIER) in Anchorage, Alaska, in August 2015, a part of President Obama’s climate change initiative.

For his piece “Sonic Physiography of a Time-Stretched Glacier,” Burtner recorded the sounds of Matanuska Glacier, located about 160 kilometers northeast of Anchorage, Alaska, not far from where he grew up. He placed 19 microphones all over the cliff face at the foot of the glacier, from top to base, to record the trickles, creaks, and groans of the slowly melting ice. He then time stretched the glacier sounds up to 8 times their original timescale, amplified the resonances within the sounds, and removed ambient noise to isolate the glacier’s sounds.

In the resulting soundscape, the high-pitched pings are from individual melted water droplets and trickling meltwater on the glacier surface. Lower tones are of ice in the interior and at the base of the glacier groaning under deformation stresses. The glacier terminates in the ocean; treble pitches are from water moving through underwater crevasses in the ice.

Burtner then accompanied the computer-synthesized glacier music with woodwinds, horns, strings, and percussion instruments, which played complementary chords and rhythms to bring out the haunting tune of a melting glacier.

 

The World(s) Keeps on Turning

Ever wonder what the TRAPPIST-1 exoplanets sound like? Some eerie blend of themes from 2001: A Space Odyssey, Close Encounters of the Third Kind, and Star Wars, perhaps? Nope, it’s actually a slightly sharp, slightly out of tune C major 9 chord missing the third and punctuated by a syncopated rhythm.

Huh?

That conclusion comes from the team at SYSTEM Sounds, a Toronto-based collaboration between astrophysicists, musicians, and app developers. Their musical interpretation of the TRAPPIST-1 planets was inspired by the unprecedented orbital resonances discovered in the exoplanet system. The seven planets have orbital periods that are nearly even multiples of each other, suggesting that the planets exchange gravitational energy and keep each other in stable orbits.

An artist’s conception of the surface of a TRAPPIST-1 planet.
An artist’s representation of a view from the surface of one of TRAPPIST-1’s planets. The seven planets, some of which can be seen in in this world’s sky, orbit in an intricate gravitational dance that makes for good music. Credit: NASA/JPL-Caltech

For every two orbits of the outermost planet in the system (TRAPPIST-1h), the inner six planets complete 3, 4, 6, 9, 15, and 24 orbits, counting sequentially inward. The orbital resonances that keep the TRAPPIST-1 planetary system alive, they found, could be easily converted into musical resonances, harmonics, rhythms, and beats. The team learned this and thought, let’s make some music.

To tease out tunes, they used a numerical simulation to speed up time by a factor of about 212 million so that the orbital frequencies of the planets shifted into the range of human hearing. When scaled like this, the outer planet completed one orbit every 2 seconds, which corresponds to a tempo of 30 beats per minute, and the orbital frequency corresponds to a low tone. The inner, more quickly orbiting planets yielded shorter, higher-pitched notes at shorter intervals. On top of that, each time two planets lined up, they had their musical software produce a percussive beat.

The result was a series of perfect, major, and minor intervals, accompanied by a syncopated rhythm. For added complexity atop this mostly resonant chord, they sonified the brightness variations of the host star itself as measured by NASA Kepler Space Telescope’s K2 Mission.

Take a listen to the TRAPPIST-1 planetary system, and then learn how to play the planets with their TRAPPIST-1 music maker.

 

Put a Ring on It

In honor of the end of NASA’s Cassini mission on 15 September 2017, SYSTEM Sounds decided to apply their astromusical talents to Saturn’s most iconic feature: its extensive ring system.

The team is no stranger to sonifying Saturn-based science—they’ve put to music scaled intensity maps of the rings, gravitational resonances of its moons, and modal oscillations within Saturn’s atmosphere. For their ring composition, the team converted a section of the highest-resolution color picture of Saturn’s B ring into a 4.5-minute musical piece for harps and drums.

Saturn’s B ring at ultra-high resolution.
With the ultrahigh resolution that the Cassini spacecraft used to grab this photo, the many layers of Saturn’s B ring almost look like the harp strings used in its sonification. Credit: NASA/JPL-Caltech/Space Science Institute

The brightness of each pixel in the picture, imaged by Cassini on 6 July 2017, determines the pitch and intensity of the harp notes, where brighter pixels correspond to higher-pitched and louder notes. The notes correspond to the first 13 notes in a harmonic series, a musical scale where the frequency of each note in the series is an integer multiple of the base note’s frequency. Each pitch also matches to a specific percussive sound like a bass drum, snare, tom-tom, or cymbal.

The result sounds like a mad quasi-techno beat that wouldn’t be out of place as the background music for a James Bond car chase or an NCIS lab analysis scene.

If you’re a harpist or drummer and want to perform Saturn’s B rings, you can even download the sheet music for yourself.

Shake It Out

In this case, the shake, rattle, and roll is an indicator of a pretty huge problem. Human-induced earthquakes in Oklahoma, to be exact. Mostly caused by the injection of wastewater after oil production and hydraulic fracturing, the increasing rate of induced earthquakes has been a persistent concern in the central United States.

As part of a 2015 investigation into the connection between increased oil and gas development and increased seismic activity in the region, a team at The Center for Investigative Reporting’s Reveal news site converted earthquake data from the Northern California Earthquake Data Center into a synthesized musical piece that emphasizes the quickening tempo of earthquake activity in Oklahoma from 2005 to 2015.

In their sonified piece “The Oklahoma Shakes,” each articulated note is a single earthquake event. The duration and magnitude of each Oklahoma quake was translated into the tone and strength of a note, with lower and louder notes correspond to bigger and stronger earthquakes. The extra fades and ringing effects were added simply for musicality’s sake.

 

Earth Blues

Nothing seems to better capture the sorrowful knowledge that we’re warming our planet than a string quartet playing the ever-rising temperatures of climate change.

In this piece, geographers, environmental scientists, and musicians from the University of Minnesota–Twin Cities teamed up to turn more than a century’s worth of global temperature data into chamber music. The composition, created by then undergraduate Daniel Crawford, is arranged for a string quartet. Each instrument represents a latitude range in the Northern Hemisphere: the equatorial low latitudes on cello, the midlatitudes on viola, high latitudes on second violin, and the Arctic on first violin.

The pitch of each note was tuned to the average annual temperature across the region, scaled from surface temperature analyses from the NASA Goddard Institute for Space Studies. Each instrument plays one quarter note for each year, from 1880 to 2015, with low pitches representing cold temperatures and high notes representing hot temperatures. By the end of the composition, the slow, steady progression of chords has noticeably shifted to higher frequencies, especially for the Arctic violin.

This video starts with an explanation of the project, and the music begins at minute 1:55.

Climate change has never sounded so poignant.

—Kimberly M. S. Cartier (@AstroKimCartier), News Writing and Production Intern

Citation: Cartier, K. M. S. (2018), Dropping the beat with some geoscience data, Eos, 99, https://doi.org/10.1029/2018EO090891. Published on 25 January 2018.
© 2018. The authors. CC BY-NC-ND 3.0