A NASA rover that has been examining Mars for the last four years has been recording audio from the planet. On this remote world, located 156 million miles away in space, even mundane noises like wind and machinery are strange to human ears. This is attributed to Mars’ atmosphere, which has a density only about 1% that of Earth’s, influencing the volume, speed, and character of sound.
Describing the sounds Perseverance has picked up at Jezero crater proves to be complex. It bears a resemblance to the haunting ambient noise from Stanley Kubrick’s “2001: A Space Odyssey,” but you can listen for yourself. Perseverance has a Soundcloud account where users can hear the latest sounds captured from Mars. NASA recently showcased some of the exceptional audio that the rover has gathered.
Upon landing on Mars in 2021, the rover came equipped with cameras, drills, tubes for rock samples, and two microphones—common gadgets that anyone could buy online. NASA made only minor modifications by adding small grids to guard against Martian dust. One microphone, referred to as the SuperCam, is positioned on the rover’s head and has captured the majority of the audio; the other is secured to the body. These audio recordings are altering scientists’ perspectives on Mars.
This marks the first occasion where humans have been able to hear the sounds of another planet. “We’ve all admired the stunning visuals from Mars,” stated Nina Lanza, a scientist at Los Alamos National Laboratory, in a NASA video, “but having sound to complement those visuals makes me feel almost as if I’m right there on the surface.”
Researchers released the inaugural study of Mars’ acoustics in the journal Nature, based on the recordings from Perseverance, in 2022. Mars is significantly quieter than previously assumed, not just due to its uninhabited nature. The rover team initially believed the microphones had ceased functioning because of the absence of sound. The primary cause of this silence is Mars’ low atmospheric pressure, which fluctuates with the seasons.
The research revealed that the thin air of Mars, predominantly carbon dioxide, impacts sound waves in unique ways. On Earth, sound travels at approximately 767 mph. On Mars, lower frequencies move at about 537 mph, while higher frequencies travel a bit faster at 559 mph. The thin atmosphere also leads to rapid sound decay. A sound that can be heard from 200 feet on Earth fades to silence after just 30 feet on Mars, with higher-pitched sounds evaporating even more quickly.
“The microphones on Perseverance are typical devices that anyone could purchase online,” remarked Justin Maki, a NASA scientist, in a video. “Sounds on Earth possess rich harmonics with various frequencies, providing depth to the audio. On Mars, the atmosphere dampens many of these higher frequencies, leading to a more isolated, subdued sound compared to Earth.”
This information has revealed to scientists that some of the earlier models regarding sound transmission on Mars were flawed. “The Martian atmosphere can project sound farther than we initially believed,” Lanza noted. In other words, Mars can indeed carry a tune.