Acousticians sometimes speculate about how conversations might carry on alien worlds. Of course, you’d have no time to chat if you stood in the open air on Mars: Your blood would boil you to death in seconds. But what about those final screams?
No matter where you are, your voice is a product of how swiftly pressure waves move through your larynx and the frequency at which your vocal cords vibrate. But when shouted into different gases of varying densities, the same noises take on new forms. Here’s how a few extraterrestrial atmospheres could change your tune.
Earth: Human vocal cords quiver at frequencies adapted to a Goldilocks atmosphere—not especially dense or light. Our air’s plentiful nitrogen and scant carbon-dioxide molecules don’t absorb many vibrations, so sound also happens to carry well.
Mars: You’d struggle to be heard on the Red Planet: Its atmosphere is 95 percent carbon dioxide—the molecular bonds of which absorb vibrations extremely well—so even speakers blasting at full volume would barely be audible 30 feet away. The chilly air’s chemistry also makes audio move sluggishly, slowing down your croons to a husky bass.
Titan: Saturn’s moon is the most Earth-like world we’ve studied, but its gas mix is about 50 percent denser than ours. Thick, cold air would slow the tremor of vocal cords and the speed of sound itself, deepening your voice and giving it a rasp. The sultry tones would travel far thanks to abundant nitrogen gas, which doesn’t do much dampening.
Venus: These thick, chowder-like climes would drop your pitch about half an octave because the heaviness slows your vocal folds’ wiggling. At the same time, though, waves move quickly through the fog, simultaneously giving you a sort of squawky quality—sometimes compared to Donald Duck.
Other worlds: The rest of the rocky bodies orbiting our sun are virtually silent, as is the case in open space. There isn’t enough gas in their thin or nonexistent atmospheres to carry sound waves at all. A few locales might manage to project the ruckus of, say, a sci-fi movie explosion, but squeaks on the scale of a human voice would falter.
This story originally published in the Noise, Winter 2019 issue of Popular Science.