University of São Paulo: In the atmosphere of Mars, sound has two different speeds

An article published in the journal Nature last week revealed that, on Mars, sound has two speeds, which causes a delayed effect on hearing.

The discovery came from an analysis of the five hours of sound captured by the microphones of NASA’s Perseverance rover, which landed on the red planet in February last year. The audios were the first sound recordings from the red planet.

As professor Enos Picazzio, from the Institute of Astronomy, Geophysics and Atmospheric Sciences (IAG) at USP explains, “the propagation of sound anywhere depends on the medium”, that is, even here on planet Earth, sound propagates with different in water and air.

From the analysis of the rover’s audio, scientists have confirmed for the first time that the speed of sound is slower on Mars, traveling at 240 meters per second compared to 340 meters per second on Earth. However, what really surprised the researchers was when, in the same medium, the laser sound traveled 250 meters per second – 10 meters faster than expected.

“They found that higher frequencies, which would be the high-pitched sounds, have a slightly higher propagation than the lower sounds”, explains Picazzio, clarifying that the fact can be explained by the different conditions of temperature, pressure and composition. atmosphere of the planet.

Through a practical example, the professor illustrates that, on Mars, “we might not be able to hear or decipher music in the same way as on Earth”.

According to Picazzio, the finding will help scientists refine the known model of the Martian atmosphere and guide future experiments involving sound in other bodies in the Solar System.