New Scientist’s February 2021 “Don’t Miss: Listen”
Read about OOL in “Nature: The Sound of Stars”
Astronomy “Octave of Light” turns exoplanet data into music
Produced by David Ibbett & Beth Sterling, Mastered by Bob Ludwig,
Presented by Multiverse Concert Series
Art by Marlena Bocian Hewitt
Videos by the Charles Hayden Planetarium, Museum of Science, Boston
Our album was funded on Kickstarter and produced entirely through
isolation recordings during the COVID lockdown
International mixed-media artist and science illustrator
Marlena Bocian Hewitt is Octave of Light’s commissioned artist.
She is creating not only the album cover, but a full set of works exploring
exoplanet spectroscopy - to be displayed alongside the music in select venues.
Each composition has an accompanying painting:
Watch David’s talk with the Science Museum of Virginia:
Octave of Light is inspired by the search for life on exoplanets, and the clues that might reveal life’s presence: chemical signs like water vapor, methane, and oxygen.
Over the past year, I’ve been working with Roy Gould of the Harvard-Smithsonian Center for Astrophysics, whose book A Universe In Creation inspired many of the pieces on the album.
Roy argues that we live in a universe finely tuned for life: from the diversity of chemical building blocks in nature, to the abundance of fertile planets for life to take root.
- will we find life on an exoplanet in the next decade?
Most exoplanets are detected as shadows moving across their parent stars via the transit method. Sensitive telescopes detect minute fluctuations in the light of a distant star as a planet passes across its surface:
The glare from a star obscures the planet completely at a distance, but we can detect its shadow!
As if this wasn’t impressive enough, a telescope equipped with a spectrograph can spit the light into its component colors and deduce which ones are missing. By taking the negative, we then get the color of the planet itself!
The spectrograms, courtesy of Roy Gould, come out looking like this:
The spectrum of exoplanet WASP-39b, with an atmosphere containing water vapor, sodium and potassium. Credit: NASA-Smithsonian
These graphs tell us a lot, as specific wavelengths (x-axis) match to specific chemicals in the planet’s atmosphere. That big dip at 0.58 corresponds to sodium! Some elements show up as a single dip, and others give rise to an intricate pattern spanning a wide range of wavelengths.
Although these lines denote ‘colors’, sadly our eyes can’t see them. Not only are they out of visible range (being mostly in the infrared), but they are also spread too widely to fit within the frequency range of our eyes. Humans can see colors between 430–770 THz (almost one doubling of signal) so even if we shifted the infrared frequencies up, we would still see only a tiny slice of what is there. We would need around 4 times the bandwidth (i.e. four frequency doublings) to perceive the spectrum of planet WASP 39-b shown above.
As a composer I began wondering, if we can’t see exoplanets
- could we hear them instead?
Compared with the feeble 1 octave (one doubling of frequency) of our eyes, our ears can hear a massive 8-10 octaves: 20-20,000 Hz!
This is certainly enough room to fit the data,
and so I got to work…
Light can easily be translated into sound because - like sound - light is a wave. Waves have a wavelength (literally, how long is each wave), and the proportions of one wavelength to another can be preserved even when sped up or slowed down by multiplying the entire series by the same number.
As light wavelengths are sooo short, they needed to be multiplied by a big number to be within audible range. I chose 2^37 - that’s 37 octaves lower than the original frequency!
However, because it’s a multiple of 2, the pitch classes are preserved (although rounded to equal temperament). A G in the sonifications is still a ‘G’ in the data - just a very high one!
Here is the first sonification I made:
Credit: NASA Smithsonian
This spectrum eventually Track 1 on the album - Water Romanza.
At the beginning, you can hear soprano Beth Sterling singing these notes as the cantus firmus of the piece, then joined by violinist Amelia Sie with the romanza melody.
Credit: NASA Smithsonian
This is how we started the trailer! We all know methane as a flammable gas, but its complex molecule (and therefore complex chord) allows it to be clearly spotted in a spectrogram. Methane can arise on a planet without living things, but -
- finding methane and oxygen together strongly suggests life’s presence
This is because oxygen is so reactive that it quickly combines with methane to produce carbon dioxide and water":
CH4 + O2 = CO2 + H2O
Finding both together means they are being continuously produced - perhaps by living things!
Exoplanet spectrograms are even more complex, making for richer spectra and even more complex chords. The amazing thing is that we can break them down into their component elements to see what is there.
The last three ‘notes’ of WASP 39-b match up to notes 3-5 of the Water Vapor spectrum above. Therefore, we can see - and hear - that the planet’s atmosphere contains water vapor!
Not only this, but the individual dips at approx. 0.58 and 0.768 reveal the presence of sodium and potassium respectively - audible as Bb and F.
Throughout the album, you'll learn a musical language of molecules, elements and exoplanets - woven into songs for soprano, piano, violin and electronics.
Amelia Sie, violin. Beth Sterling, soprano.
David Ibbett, piano & electronics
Praise for David’s music and Octave of Light
Octave of Light featured in New Scientist - February 2021 “Don’t Miss: Listen”
“The discovery of habitable exoplanets. Music to his ears.” Big Picture Science Radio Show & Podcast on Octave of Light Album
“Composer David Ibbett encodes the dreams and details of complex physics phenomena into music to help audiences appreciate their splendour.” Nature
“The opening track “Water Romanza”; a sprawling and gorgeous introduction to the world Ibbett has created, bolstered by Sterling’s impressive vocal” Andrew Bourque of the Allston Pudding on Octave of Light album
"The music is like Mozart mashed up with Club Beats and Electronica" Original Gravity Concert Series
“It will be an out of this world experience when David Ibbett… debuts his first album, "Octave of Light," in a performance at the Boston Museum of Science” Richard Duckett, Worcester Telegram & Gazette
“A WPI professor is set to debut his first musical album this week and it's out of this world.” Spectrum News Channel, Worcester MA
“Is life sustainable on other planets? If music is a clue, David Ibbett… can tell you the answer.” Jessica Messier, WPI Blog
"Some may notice their toes are tapping while they groove to his exciting rhythmic complexities" Boston Music Intelligencer
“Molecules are halfway to being musical instruments to begin with… like a violin string, a molecule vibrates and rotates and resonates. That's similar to what David is actually doing with musical instruments.” Roy Gould, Harvard Center for Astrophysics
“I felt completely immersed in journey into the micro world beyond our senses. [David has] successfully taken the whole audience into a place we couldn't experience in another way than art and music!“ Anna Barnacka, Black Hole Researcher
"David's music [for piano and electronics] is symphonic, lush, virtuosic, meticulously crafted, and full of so much heart" Sophia Subbayya Vastek, pianist
Music by David Ibbett
Art by Marlena Bocian Hewitt
Science by Roy Gould, Harvard-Smithsonian Center for Astrophysics
Animations by the Charles Hayden Planetarium, Boston Museum of Science
Soprano - Beth Sterling, Violin - Amelia Sie
Piano/Electronics - David Ibbett
Producer - David Ibbett, Associate Producer - Beth Sterling
Mastered by Bob Ludwig
Recorded at Falcetti Pianos
Eartesters - Micah Brown, Corinne Decost, Maya Rakoczy, Alexey Veraksa
Presented by Multiverse Concert Series
Funded on Kickstarter
