Back in February 2021, the Perseverance rover landed on Mars and brought with it an array of instruments, including cameras, lasers, and the first microphone to function and record on the planet.
With the help of this state-of-the-art technology, an international team of researchers analyzing the sounds captured by the Perseverance rover has determined the speed of sound on Mars.
Their new study reveals how fast sound travels through the thin and mostly carbon dioxide atmosphere, how Mars might sound to human ears, and how scientists can use audio recordings to probe subtle air-pressure changes in another world, as well as gauge the health of the rover.
Using recorded sounds generated by the rover, such as shock waves from the rover’s laser used to cut rocks as well as flight sounds from the Ingenuity helicopter, the researchers were able to compare the Martian sounds to Earth sounds, determining that sound travels 100 meters per second slower on Mars than on Earth.
The researchers also realized through these recordings that there are two speeds of sound on Mars: one for high-pitched sounds and one for low-pitched sounds. This means that future Mars astronauts could experience difficulty in communicating, as they will hear higher-pitched sounds sooner than lower-pitched sounds, even if they come from the same place.
Additionally, the microphone also allowed for measuring the temperature on Mar’s surface in and around the rover, as sound travels at different speeds depending on temperature. By measuring sound speed every time Perseverance fired its laser, the researchers were able to calculate rapid temperature changes. The research team also plans to continue monitoring and analyzing sounds from Mars over the course of a year to learn more about fluctuations during different events on the planet, such as during the winter months or during dust storms that are common on the planet.
“It’s a new sense of investigation we’ve never used before on Mars,” says Sylvestre Maurice, an astrophysicist at the University of Toulouse in France and lead author of the study, in a statement. Maurice is referring specifically to the Perseverance rover’s SuperCam, which has a microphone built into it. “I expect many discoveries to come, using the atmosphere as a source of sound and the medium of propagation.”
Listen to some of the first-ever recordings from the Red Planet below.