NASA’s mobile robot “Perseverance” revealed the secrets of the amazing sound scene of Mars, and it was recorded by the rover that the Red Planet is calm, in which sound travels slowly and at two different speeds.
As soon as the US space agency’s robot landed on the surface of Mars a little more than a year ago, it sent the first audio recording by means of a microphone on Mars in the history of space exploration, at frequencies that the human ear could hear, achieving what previous missions could not.
Behind the vehicle’s roar, a gust of wind could clearly be heard in this recording. Thus, after the exploration vehicles for 50 years have sent thousands of images to Earth, the red planet emerged from “acoustic nothingness”, as noted by the National Center for Scientific Research in France, commenting on the publication of a study in this regard in the scientific journal “Nature” on Friday.
And this first audio recording showed the presence of previously unknown turbulence systems on Mars, according to the study’s lead author, Sylvester Morris, who is the co-scientific director of the robot’s “SuperCam” instrument, on which the microphone designed by Isae-Supaero in Toulouse, France, was fixed.
But this recording was not enough to form a clear picture. Since Mars is very quiet most of the time, two “active” sources had to be used to capture the assets provided by the robot before sending it to Mars, according to Maurice, an astrophysicist from the Institute for Research in Astrophysics and Planets at the University of Toulouse, explained to AFP.
His team benefited from the miniature helicopter “Ingenuity” accompanying the robot, and from the laser shots directed at the Martian rocks to examine their chemical composition through the sound of it colliding with them. The researcher pointed out that these shots provided “a very localized sound source, at a distance of between two and five meters from its target, and the exact timing of its firing was known.”
It was possible to measure the speed of sound in the field, and it is 240 meters per second, while it is 340 meters per second on planet Earth. Unsurprisingly, the speed of sound is slower, given the composition of Mars’ atmosphere “96 percent of which is carbon dioxide, compared to 0.004 percent on Earth” and its very low pressure “170 times that of Earth”.
However, the surprise came from the sound of the laser, which reached 250 meters per second. “There I panicked a little! I told myself that one of the measurements might not be correct, as there is only one speed of sound on Earth, near the surface,” said Sylvester Morris.