The speed of sound on Mars is different from the speed of sound on Earth

Thanks to NASA’s Percy rover, Scientists have been able to calculate the speed of sound on Mars. The Mars2020 spacecraft has already amazed us in the past by recording sounds first in space and then on the surface of the Red Planet thanks to its SuperCam microphone.

A microphone attached to the rover did not collect any usable data during landingBut the device has survived the impact on the surface e He got votes from Jezero pit February 20, 2021. About 10 seconds of recording: The winds of Mars are clearly seen for a few seconds, as well as the mechanical sounds of the rover operating on the surface.

In this article you will find:

The speed of sound on Mars: the new discovery

These sounds gave impetus to Baptiste Scheide of Los Alamos National Laboratory in Los Angeles and his colleagues who were then able to measure the speed of sound on Mars. The findings were presented at the 53rd Conference on Lunar and Planetary Sciences, which was held from March 7-11 in Texas.

Scientists used SuperCam LIBS analysis to determine the speed of sound on Mars. In this analysis, some targets are selected on the surface, and in the direction of each of them, from 5 to 10 bursts of laser shots are fired at different points a few millimeters apart. The analysis takes about 20 minutes and the data is collected thanks to the expansion of the plasma caused by the laser in the Martian atmosphere, which generates a shock wave that propagates up to the microphone as a high-frequency audio signal. (>2 kHz).

Thanks to the precise synchronization between the laser and the microphone, the propagation time can be determined with an accuracy of ±10 s. Then, to determine the speed of sound at the surface, the scientists measured the arrival times of sounds in Percy’s SuperCam microphone: Sound travels to Mars at 240 m/s, which is less than the speed of sound on our planet which rises to about 340 m/s. in the air (a number that varies with temperature). The propagation time for a target located at a height of 2 m is 8.33 ms, taking into account a sound speed of 240 m / s.

Each laser shot has an accuracy of ±0.5%, so the data obtained is very accurate compared to predictions made in the past. An interesting fact is that of the difference in speed between high and low frequencies. Sounds below 240 Hz have a lower speed, about 230 m/s. This does not happen on Earth, Sounds travel within the audible frequency range (20 Hz to 20 kHz) at a constant speed!

Mars’ privacy

Selfie image taken by NASA’s Perseverance spacecraft on September 10, 2021. Source: NASA/JPL-Caltech/MSSS

Scientists have called this phenomenon “the Martian peculiarity”:

Due to the unique properties of low-pressure carbon dioxide particles, Mars is the only planetary atmosphere in the Solar System that experiences a change in the speed of sound in the middle of the audible frequency range (20 Hz – 20 kHz).

Thus, according to the scientists, for a sound wave with a frequency greater than 240 Hz (the relaxation frequency), the vibrational modes of the CO patterns are activated by the collisions, They don’t have time to release their energy. In this case, it is as if the medium has only 5 degrees of freedom compared to 7 at low frequencies (3 translational modes, 2 doubly degraded modes and 1 doubly degraded vibrational mode).

It can create a unique listening experience on Mars with early access to high-pitched sounds instead of bass.

In short, we advise you not to listen to music on Mars because it will be perceived in a very different way than what happens on Earth. However, we’re safe because that wouldn’t be possible anyway!

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