On Mars, visitors from Earth are like loud neighbors who refuse to settle down. On Mars, though, the noise doesn’t travel far — it fades out in a hurry.

We’re learning a lot more about how sound travels on Mars from one of those noisy visitors, the Perseverance rover. It’s been crawling across Mars for 21 months. It’s looking for evidence that its landing site could have been a comfortable home for life in the distant past.

Perseverance has two microphones — the first on the surface of any other world. And most of the time, they hear almost nothing — only an occasional sigh of wind. ...

Most of what they have heard has been the rover itself. It’s recorded the motions of its robotic arm ... a device that clears off rocks for study ... and the whir of Ingenuity, a small helicopter that hitched a ride with Perseverance. ...

It’s also recorded the clicks of a laser that zaps the rocks. ... The timing of the zaps has helped scientists learn more about how sound travels on Mars. The Martian atmosphere is thin, cold, and made almost entirely of carbon dioxide. In that environment, the speed of sound is only about two-thirds as fast as it is on Earth. High-frequency sound waves travel faster than low frequencies. But the high-end waves fade out much more quickly — letting the bass line rumble a little farther across the quiet landscape.

Script by Damond Benningfield

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