Scientists have discovered that the speed of sound on Mars is very different from the speed recorded here on Earth. The discovery was announced by Baptiste Chaide, a planetary scientist at Los Alamos National Laboratory, at the 53rd Lunar and Planetary Science Conference on March 7-11.
Apparently, on the Red Planet, high-frequency (treble) waves travel faster than low-frequency (bass) waves—that is, if we can live there without special suits, we’d be able to make the loudest sound the quietest. Will listen before
This is because the speed of sound can change depending on the density and temperature of the medium through which it passes. Thus, the denser the medium, the faster the sound will travel through it.
The density of Earth’s atmosphere is about 1.2 kg/m. In this, sound travels at about 343 meters per second at 20 °C, 1,480 meters per second in water and 5,100 meters per second in steel. The atmosphere of Mars is much less dense, about 0.020 kg/m. In itself, this fact would already have propagated sound differently on the two planets.
But there are other factors that can affect the speed of Mars’ sound waves. Among them is the heating of the planetary boundary layer – a band of atmospheres just above the surface, which generates convective updrafts creating strong turbulence.
How was the speed of sound measured on Mars?
Measurement of the speed of sound on Mars was only possible thanks to instruments on NASA’s Perseverance rover: a microphone installed on the Supercam, and a laser that could trigger a perfectly timed noise.
To calculate the sound dissipation on the neighboring planet, the scientists measured the time between firing the laser and the moment the sound reached the microphone, at 2.1 meters in height. The results show that it spreads near the surface at a speed of about 240 meters per second.
The scientists also explain that the unique properties of carbon dioxide molecules at low pressures on Mars cause a change in the speed of sound, right in the middle of the bandwidth audible to humans.
At frequencies above 240 Hz, the vibrational mode activated by the collision of carbon dioxide molecules does not have enough time to relax or return to its original state, resulting in sound at higher frequencies than 10 meters per second at low travels at a higher speed.
This is what scientists call a “unique listening experience” on Mars: higher pitched sounds reach the listener earlier than lower ones.
The research team also used the Supercam sensor to measure large and rapid temperature changes on the planet’s surface, as temperature fluctuations also change the speed of sound. These data could help scientists understand our red neighbor even better.
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