Lessons learned from sounds coming from Mars
Audio 01:24
The Ingenuity helicopter pictured during its first successful attempt to fly three meters above the ground of the planet Mars, April 19, 2021. AFP - HANDOUT
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2 mins
Researchers have succeeded in obtaining sound coming from the planet Mars, thanks to a microphone installed on a camera.
What they recorded may seem banal, but is nevertheless rich in scientific lessons.
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The sound of a gust of wind was recorded on Mars using a microphone placed at the top of the
Perseverance
robot's
camera .
A sound that may seem harmless, but that says a lot about
the planet Mars.
“
Wind and Turbulence
”
“
That's what we first heard on Mars.
There are times when you don't hear much because Mars is getting very quiet.
There are times when Mars can be very quiet atmospherically.
But the first recordings rather highlighted the influence of wind and turbulence
,” says Franck Montmessin, CNRS researcher who is part of the team in charge of the project.
Behind this recording, there is not only the curiosity to listen to
another planet
.
The study of sound on the surface of Mars is indeed rich in scientific lessons.
“For example, the speed of sound is temperature dependent so you can almost use the microphone as a temperature probe.
It also allows us to understand how a CO2 atmosphere is able to transfer the energy associated with acoustic waves.
It gives us information on the intrinsic characteristics of this atmosphere.
These are things that we cannot recover otherwise
, ”explains the scientist.
On Mars, sounds travel slower
With this mic, the researchers also discovered that sound travels slower on Mars than on Earth.
240 m/s against 340 m/s on Earth.
And even more surprisingly, by comparing the sounds emitted by the
Ingenuity
helicopter and the Rover's laser, the scientists discovered that on Mars, low-pitched sounds are faster than high-pitched ones, whereas on Earth there is only one single speed of sound.
"
The attenuation of sound is stronger on Mars than on Earth, particularly the treble which is lost very quickly, even at a short distance
", which would make "
a difficult conversation between two people separated by only five meters
", explains the CNRS .
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