ABOUT THE ESSAY:
Dana's essay incorporates original space-craft recorded atmospheric sounds, provided by the laboratory of Dr. Don Gurnett at the University of Iowa. The text is included below for the ease of listening.
Imagine, if you can, one single, stranded molecule in space –not even a pinpoint in the darkness. In the whole of the universe, a molecule is truly an island to itself, its nearest neighbor some ten million molecular body-lengths away. If it were a person on Earth heading east from San Diego, it would not see another person until New York, and these two friends might then hike, swim, and wade their way to Denmark before finding anyone else. That is how isolated it is, this thing you cannot quite imagine: a solitary something vanished into a sea of nothing.
On Earth there are so many molecules in the air that they are always finding each other. If a molecule of Earth’s atmosphere were a person standing in a room in San Diego, the nearest person would be standing in the same room, ten feet away. As a rule, molecules on Earth are content to stand at rest until something sends them jostling forward into rhythm, and then they might become a wave of sound. It could be the click of a needle on vinyl; the chime of an elevator bell; the splash and shell-crack of boiling eggs –whatever it is, a sound is just a mechanical movement, a set of vibrating parts transferring energy down a line, compressing and relaxing like a child’s spring toy. A sound is nothing more than one molecule sent shaking towards another.
So picture again the single molecule and its far-flung neighbor in space. They may be distant, but they are not hopeless; they can propagate sound waves between them just the same as molecules on Earth. But there is one catch: because sound needs stuff to travel through and because space doesn’t have much stuff at all, the long stretch between molecules prevents all but the lowest frequencies from travelling any distance. There is simply not enough matter in the greater vacuum of the universe for the short, familiar wavelengths of the needle click, the elevator chime, and the shell crack. No human ear could ever truly hear a sound shaped in space, for it is just too low.
But still this is not the end, for humans have heard a few of the universe’s mumbled sounds. Their low waves can be recorded and compressed until they are audible. Stars, moons, planets and all the breathless Bible-black spaces between –they speak in waves, in bouncing electrons and dancing particles and in light. And sometimes, we would just like to listen.
Just barely above the clouds in Earth’s atmosphere, ions are sent buzzing by the static charge of lightning strikes. Each spark releases electromagnetic radiation and energy, along with a telltale click known as a sferic –short for atmospheric. When they come through our radio receivers, sferics sound like twigs snapping underfoot, or fat sizzling in the pan, or cellophane crinkling down.
When lightning is more distant, static clicks lengthen into higher-pitched things called tweeks. Tweeks take on the more musical quality of the higher ionosphere into which they are ducted, sounding off like a chirping chorus of birds at dawn or the strange tin spray of bullets firing overhead. Every so often, a wonderful thing happens when one tweek is stolen away from the rest, drawn into a magnetic field arc, and taken in a spiraling curve round the planet. The movement makes a sound that splits into high frequency and low --the higher traveling fast and piercing ahead, ringing, and the low lagging behind and slinking into silence. Because they sing like slide whistles these last sounds are called whistlers, and when you close your eyes to hear them you might catch them curving through your mind, swooping open into a wide letter “C.”
For all their charm, whistlers are not unique to our planet. There are earthly whistlers just as there are Jovian whistlers, and Saturnian whistlers and Martian whistlers; it is all the same. They come in varieties pure-toned, diffused, and multi-hopped. Some sound like an arcade at evening, the pew pew pew of laser guns. Some sound more ominous, like the tin gargle of robots, or voices played backwards and hushed. Some sound like exactly what they are: the strange words of a planet speaking its no-name tongue.
Meanwhile, away from the clattering regions of whistlers and tweeks, a 12-inch disk of gold-plated copper brings the sounds and songs of Earth into places we have never been. In 1977, twenty-seven songs and twenty-one sounds were cast into a golden record and bolted to the side of the Voyager 1 probe as it was prepared for its one-way trip into space. 3.6 billion years of life were distilled into the sounds of mud pots gurgling, blacksmiths hammering, surf lapping up to the shore. If the universe holds other bodies, now they will hear the sounds of ours: a kiss on the cheek, a pat on the back, a blended heartbeat of an EEG and a pulsar. They will hear the first movement of Beethoven’s Symphony No. 5 in C Minor, Louis Armstrong’s Melancholy Blues, the melodies of Peruvian panpipes and the 2,500 year old stylings of Chinese strings.
The twentieth track on “Music of Earth” is a Navajo night chant, which lasts for just fifty-seven seconds of the album’s ninety-minute run. It begins with the soft shaking of gourd rattles, and then a pair of male voices emerging in unison. They stay low together until suddenly one voice jumps to falsetto, trilling at the top for a godly moment before skimming down slowly to rejoin the other. At the height of this note you can imagine the dancers’ twisting fireside shapes, their bodies holding from dusk to daybreak in endless song.
One day, Voyager 1 will lose its capacity to transmit its whereabouts back to Earth; as it makes its way further into space, the Voyager may outlast us all. The only evidence of a planet and its people will be two voices chanting in turn, and a spacecraft etched with the words, “To the makers of music –all worlds, all times.”
It took Voyager 1 thirty-six years to move past the sun and into all the rest of it, the spaces between the stars. This makes its excursion the longest vicarious trip humans have ever taken. To reach interstellar space one must first cross the layer called the heliopause, which is exactly what it sounds like: the boundary where the sun’s solar wind meets the open universe, the pause before a great untethering. Voyager 1 has recorded over 225 days of radio noise post-heliopause, and now we only await to find what calm or chaos lies ahead.
If there is a calm place in the universe it might be Saturn’s ice-moon Enceladus, whose blue-veined surface likely conceals a whole ocean of water. William Herschel, astronomer and composer, discovered the moon in 1789 and named it after the Greek Titan. Radio waves move low through the atmosphere of Enceladus, and when their sound is transformed for our ears the waves seem to whoosh by like an echo dream. In 2002 the composers Terry Riley and Stephen Taylor wrote a piece called Sun Rings, which made use of the faraway sounds of Enceladus. “I recognized these sounds as natural sounds somehow,” Taylor said. Riley had also recognized something in the static: a minor third interval. Though it passes quickly, you can tell a minor third by its two quick notes –the first two of “Greensleeves” or “Light My Fire”; the lul-la in Brahm’s Lullaby or the lilting oh of “The Star Spangled Banner.” Riley composed his whole movement around the minor third, looping just these two notes throughout the piece. When he was finished with it he said “Do stars welcome us into their realms? I think so or we would not have made it this far.”
Do stars welcome us into their realms? Do we welcome them into ours? On November 13, 1833, the sky fell, rusted red and wrapped the steeples in an odd light. That night the Leonids came to us, so many meteors that an Alabama newspaper guessed thousands and even millions of a most awful and sublime appearance. A sketch of the shower, published in an old Christian periodical, shows an entire town standing watch in the streets. More than half of the frame is sky, and nearly all of that is darkness slivered and silvered by stars. Some of the townsmen look solemn and others look frightened; some clutch the shoulders of friends; others place their hands to their own faces, over the eyes or across the brow. There are people praying, crouching, kneeling, pointing, lying down and getting up. None of them knows that at this particular moment, their planet is being swept through a strip of dust on its way round the sun. None of them knows how warm this debris can become as it passes through the atmosphere, even while bits of it catch fire right before their eyes. As the people line the streets to peer up and out —a few of them begging forgiveness —they have no idea that they are only witnessing a sign of their own universal motility. That they are, in fact, hurtling through space.
In radio wave recordings, the Leonids wail as they cross the atmosphere and drag behind them a short trail of ionized particles. The wind blows this trail of particles around, rattling the noise as if it were a visible stream, as if it were zagging light itself. The Leonids sound out like a wavering siren, tinny and high; or a section of flutes playing in bursts, or champagne glasses singing at the rims, singing for days. If you turn the dimmer of a light too quickly, the filament will shake and the bulb will release a shrill tone that has its own name: lamp sing. This shaking motion, this is what the Leonids are like. As if you could hear the spiraling light.
Well beyond our towns, our Earth, and our solar system are the steadily revolving pulsars, highly magnetized neutron stars of a certain size and mass greater than our Sun’s. They emit radio waves in a pattern so predictable, exact, and unwavering –beat following beat –that we have used them as perfect, cosmic clocks. Every pulsar has a different sound. Pulsar B08333-45, Vela, sounds like a helicopter spinning down, a flywheel ticking, an engine slowing. If you like, pair it with a maple seed on its whirligig twirl to the dirt. Other pulsars whir the wingbeat of the hummingbird –the band-tailed barbthroat, let’s say, or the black-breasted hillstar, but maybe not the bufftailed sicklebill (and certainly these are not the blue-bellied whistlers or the bronze-tailed sferics, the ruby-throated tweeks.)
Then there is PSR B0329+54, plodding up the stairs forever. Last year thousands of people were watching when, with exactly 0.7 seconds left, Kyrie Irving made the three pointer to bring the Cleveland Cavaliers to a 99-98 victory over the Toronto Raptors. As they blinked, as the ball made it to the net, PSR B0329+54 made a quick, full turn. That plodding sound is the basketball dribbling, it is the pulsar turning, it is the crowd fingertapping, jittery beneath the seats.
Now send that basketball off into space; how far would it travel? See it go through the layers: troposphere, stratosphere, thermosphere, exosphere. See it pass through the magnetosphere, a place that sounds like a gurgling stomach, a stethoscope, a low rumbling; like the brief moment of your head dipping underwater (what would it be like, I wonder, to dip your head in and out of the magnetosphere?) The truth of it, though, is that if you could chase that basketball straight into the sky –into the magnetosphere and far past it –the sounds would stop altogether and you would only find the stillest quiet you have ever known.
ABOUT THE AUTHOR:
Dana D'Amico is an MFA candidate in creative nonfiction at the University of Minnesota. She earned her B.S. at Allegheny College studying plant biology and genetics, and her writing blends scientific research with cultural, historical, and personal narratives. Find her blogging about the intersection of art and science here, or follow her on Twitter @damico_dana.
* Original space audio recordings provided courtesy of NASA and Donald Gurnett of The University of Iowa (here), and the Jodrell Bank Centre for Astrophysics, UK