Noise evaluated for the first time
This is what it sounds like on Mars
NASA’s Perseverance Mars Rover is humanity’s eyes and ears on the Red Planet. But what is there to listen to so far from Earth? For the first time, scientists evaluate hours of sound recordings and discover a big surprise.
An international team of scientists has evaluated sound recordings from Mars for the first time – the result: silence prevails on the red planet, broken only by occasional gusts of wind. “There are only a few natural sources of sound, with the exception of the wind”, the scientists explained on the occasion of the publication of their study in the journal “Nature”.
However, the five-hour audio recordings contained a surprise: There are two different speeds of sound on Mars. The recordings come from two microphones on the US space agency NASA’s “Perseverance” Mars rover, which landed on Mars in February last year.
They have now been evaluated for the first time by a research team led by lead author Sylvestre Maurice. There was such silence on the recordings that scientists began to fear that something was wrong with the measurements. But then something could be heard, for example, the hum of the rotor blades of the NASA rover’s “Ingenuity” ultralight mini-helicopter.
Entertainment on Mars would be difficult
With their study, scientists were able to prove for the first time that the speed of sound on Mars is 240 meters per second, slower than on Earth, where sound travels at 340 meters per second. This was expected because the Martian atmosphere is 95 percent carbon dioxide and about 100 times thinner than Earth’s.
However, what surprised everyone was that the sound generated by the laser traveled 250 meters per second, faster than expected. “I panicked a bit,” lead author Maurice reported. “I told myself that one of the two measurements must be wrong because there is only one speed of sound on earth.”
So there are two speeds of sound on Mars: one for high-pitched sounds like lasers, and one for lower frequencies like the hum of helicopter rotors. “All of these factors would make it difficult for two people who are only five meters apart to have a conversation,” said the French research institute CNRS.