The Speed of Sound on Mars Is Kinda Funky, New Evidence Suggests

Using a microphone, a laser, and a few artful arithmetic, a group of scientists has measured the velocity of sound on Mars, in what’s a scientific first and one other cool discovering made doable by NASA’s Perseverance rover.

There’s tons to like in regards to the Perseverance mission, however one in every of my favourite features of the rover is that it’s able to recording audio. Early final yr, and for the primary time ever, we really bought to listen to sounds on Mars, each pure and artificial. Using its SuperCam microphone, the rover recorded blowing Martian winds, clicks from its rock-scanning laser, and crunching sounds made by its rolling wheels.

That Perseverance’s microphone would detect these sounds wasn’t a certainty, given the achingly skinny environment on the Red Planet. Sound wants a medium to propagate, and Mars, with a paltry atmospheric stress of 0.095 pounds per square inch (psi) at floor stage, doesn’t supply a lot to work with. By comparability, Earth’s sea stage atmospheric stress is round 14.7 psi.

But there they have been—discernible noises picked up by Percy’s microphone in Jezero crater. With sounds clearly audible on Mars, Baptiste Chide from Los Alamos National Lab in Los Angeles and colleagues have been in a position to measure the velocity of sound on Mars. The scientists lately offered their findings on the 53rd Lunar and Planetary Science Conference, held from March 7-11 in Texas.

The group leveraged Perseverance’s SuperCam experiment, which zaps rocks with lasers to review Martian geology and sits on the head of the rover’s mast some 6.9 toes (2.1 meters) above the Martian floor. The group took measurements from 150 laser pictures taken at 5 distinct places, whereas additionally monitoring native climate circumstances.

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By measuring the time it took the staccato-like clicking sounds to succeed in the SuperCam microphone, they have been in a position to set up the velocity of sound on Mars, to a precision of plus-minus 0.51%. They discovered that sound on Mars travels at 787 toes per second (240 meters per second), which is considerably slower than the sound of velocity on Earth at 1,115 toes per second (340 m/s).

And in an commentary that matched prior predictions, the velocity of sounds under 240 hertz fell to 754 toes per second (230 m/s). That doesn’t occur on Earth, as sounds throughout the audible bandwidth (20 Hz to twenty okHz) journey at a continuing velocity. The “Mars idiosyncrasy,” because the scientists name it, has to do with the “unique properties of the carbon dioxide molecules at low pressure,” which makes the Martian environment the one one within the photo voltaic system to expertise “a change in speed of sound right in the middle of the audible bandwidth,” because the scientists wrote. The motive for that is that sounds above 240 Hz don’t have time to chill out their power, in keeping with the scientists.

The scientists go on to say that this acoustic impact “may induce a unique listening experience on Mars with an early arrival of high-pitched sounds compared to bass.”

Unique is correct! Lots of acoustic data exists under 240 Hz, together with the low finish of music and the lowermost registers of the human voice (usually for males). Music on Mars would sound fully tousled (significantly with elevated distance), with the center and excessive frequencies reaching the listener barely earlier than the low frequency sounds, such because the decrease registers of the bass guitar and kick drum. Add one other impact of carbon dioxide, the attenuating, or dampening, of upper frequencies, and the acoustic expertise will get even weirder.

As a neat apart, the approach used to measure the velocity of sound may also be used to measure the native temperature. So along with Percy’s Mars Environmental Dynamics Analyzer (MEDA) instrument, the group has a brand new thermometer at its disposal. Looking forward, Chide and his colleagues will run extra exams to measure the velocity of sound at totally different occasions of the day and through totally different Martian seasons.