What Would Sound Be Like on Mars?

An astronomer responds to Indrapramit Das’ new short story “The Song Between Worlds.”

Sound waves and sound shadow blobs floating across the surface of Mars.
Lisa Larson-Walker

An astronomer responds to Indrapramit Das’ “The Song Between Worlds.”

In May 2012, I stepped into a landscape as alien as the wilderness of Mars: the plunging orange slopes and golden, rocky spires of Bryce Canyon, Utah. I was there for the “ring of fire” partial solar eclipse, where the moon would briefly align with the sun, blocking all but an annulus of light from our star.

While the eclipse was lovely (nowhere close to the near-religious experience of seeing the 2017 total solar eclipse, but gorgeous nonetheless), what I remember most about the trip was camping in the backcountry that night—specifically, the sound of the wind. Folded in a stand of tall pines deep in the canyon, we set up camp, ate dinner, and settled in to enjoy the peace of the wilderness. But wilderness can be very loud. As we turned into bed, the wind swept through the trees above us with a cascade of sighs. The sounds of wind can be peaceful, of course, but I was on edge. Never mind that bear encounters are exceedingly uncommon in Bryce Canyon—I had recently read about some unsuspecting fellow city person being bitten through the fabric of their tent and was sure a similar fate could befall me.

In the wee hours of the morning, an assertive sniffing sound awoke me. I was convinced that a bear was directly outside the tent, drawing swift inhales through a snout undoubtably large enough to swallow my head. I’m not sure how long I lay there, awaiting a final exit via bear, but it seemed like an eternity before I realized:

It was the tent.

With rain in the forecast, we’d installed the rain fly over our tent, an additional layer of protection that fluttered stiffly in the canyon winds that shivered our tent, rubbing fabric on fabric to perfectly mimic (to the ears of this New Yorker) the sound of a bear cartoonishly skulking around outside.

Sound is a relatively simple physical phenomenon, but the way our minds shape it can be complex. It’s a wave, but not the same kind of wave one might see in the ocean, where the medium (water, in the case of the ocean) travels toward or away from us. If sound waves were like ocean waves, we would not be able to speak to one another without blowing a constant breeze toward the listener, which is (generally speaking) not what happens. Rather, sound waves travel by creating collisions between the molecules of air between us and the origin of the sound. If I speak to you, my words vibrate the air between us until the very air in your ears vibrates. Those vibrations shake the delicate structures in your ears and, for those who can hear, funnel those signals to your brain, which decodes the vibration and makes sense of it all. Or, nonsense of it all: How we interpret the sound is separate from the sound itself. I can’t tell you how close the sound of my tent fabric is to the sound of an imagined bear—all I can tell you is that it prompted not only vibrations in my ears but a swift injection of panicky adrenaline into my blood.

Our physical environment strongly influences how we experience sounds—the density and temperature of whatever it travels through (such as air). If we were to be suddenly relocated to Mars, the thin, cold atmosphere would barely transmit the sound of our words at all. Of course, the bigger problem is that we can’t breathe the Martian atmosphere at all—it’s barely a wisp of Earth’s atmosphere and is made almost entirely of carbon dioxide, rather than the oxygen we need to breathe.

Practically speaking, sound for a human on Mars would be mediated by technology. In the outdoors, voices would be heard via the communications system built into a spacesuit, and the sounds of the environment—wind, dust, perhaps even the metallic whirring of a Mars rover—would be received from the outside via microphone. An unmediated experience of hearing and feeling the wind, as on Earth, would be impossible. To be exposed to the elements on Mars would bring not only an existential threat but profound silence on the thin, inhospitable air.

In Indrapramit Das’ “The Song Between Worlds,” it is exactly this difference between the context of sound on Earth and sound on Mars that Varuna finds so alluring. The ushengaan, the indigenous, unhearable song of Mars, exists because of the specific conditions of the Martian atmosphere: The singer of the ushengaan can hear the song within their own pressurized, air-filled helmet, but attempting to sing it outside the safety of their protective suit would bring certain death, and the song would not be able to travel far in the Martian atmosphere anyway. The ushengaan is valuable precisely because of its physical inaccessibility, much as the tourism Varuna’s family engages in has both financial and performative value because of its inaccessibility to others. In the ushengaan, the Martian shepherds have created something with a perceived value that exists outside of its worth to them—a value created through the context of their song, its unattainability, its inherent privacy.

Das never reveals what the ushengaan means to the Martians themselves—only to one particular Martian, Nayima. Nayima’s faux-ushengaan acts as a form of personal, individual expression via her interaction with Varuna. For Varuna’s parents, and presumably the other tourists who consume performative variations on this indigenous Martian art, the experience of being among the Martian shepherds (and in proximity to their art) is an elusive form of capital, the kind of wealth of experience that only the truly wealthy can easily attain. The Mars of “The Song Between Worlds” is a Mars shaped by the transactional relationships of capital—a world where the only imaginable experience is the transfer of a product (in this case, a song) from its source to its new keeper. Regardless of whether Varuna thinks of themselves as a profiteer, rising through the VJ charts by having captured the ushengaan, or a curator, protecting an artifact, they are inextricably part of a transaction whose “authenticity” is mediated by capitalistic tourism.

To date, only our spacecraft have experienced the sounds of Mars. In 2015, NASA translated vibrations from the Mars rover’s accelerometer into sound; the rover’s vibrations would have been too low in pitch for the range of human hearing, so the team shifted their pitch upward to create an eerie symphony of hums and growls representing the rover Opportunity’s traverse across the Martian terrain. Just this week, NASA’s InSight lander released sounds of the first recorded “Marsquake,” a tiny tremor from the interior of the planet, again made listenable by shifting the vibrations into the range of human hearing. Previously, though, Insight had returned what was billed as the “first-ever” sounds of Mars. The audio came from vibrations caused by the Martian wind across the spacecraft’s solar panels, captured by Insight’s sensitive seismic instruments. These recordings were supposedly the first sounds from Mars because they are the first vibrations recorded that fall naturally in the possible range of human hearing, but is that what makes them authentic? Both the sounds from Insight’s solar panels, and the thrumming of Opportunity’s wheels, have been translated from an experience that lives within the bodies of those spacefaring machines, not our own. If we could stand nearby and listen to Opportunity during its traverse, we might have heard something different—perhaps the muted crunching of tire treads over gravely red regolith, or the fizzing of grit blowing against our helmet’s faceplate. While our spacecraft tremble on the Martian plains, we humans can only approximate their experience, bound by the fragility of our bodies.

On Das’ Mars, as well as on the Mars we experience here in our nonfiction world, the hostility of the environment reveals the relationships between earthling and Martian, human and machine. Nayima’s song—true ushengaan or not—invites us to consider our own relationships to technology, our bodies, and experience. After all, much of what we consider to be “natural” sound on Earth reaches us through technology, whether it’s a call on our cellphones or streaming music over the internet. At the same time, the physical standards for astronauts prevent otherwise-qualified people who are deaf or hard of hearing from becoming spaceflight candidates—even though people with disabilities have much more practice navigating challenging environments, including via technological interventions, and may therefore be better suited for space than able-bodied people. Rather than thinking of the Martian environment as something that might limit our human experience, perhaps we can accept Das’ invitation to consider our relationships to one another—and embrace a more expansive definition of human experience here on Earth.

Future Tense is a partnership of Slate, New America, and Arizona State University that examines emerging technologies, public policy, and society.