Paris: The primary audio recordings on Mars reveal a quiet planet with occasional gusts of wind the place two completely different speeds of sound would have a wierd delayed impact on listening to, scientists mentioned Friday.
After NASA’s Perseverance rover landed on Mars in February final 12 months, its two microphones began recording, permitting scientists to listen to what it’s like on the Crimson Planet for the primary time. In a examine printed within the Nature journal on Friday, the scientists gave their first evaluation of the 5 hours of sound picked up by Perseverance’s microphones.
The audio revealed beforehand unknown turbulence on Mars, mentioned Sylvestre Maurice, the examine’s principal writer and scientific co-director of the shoebox-sized SuperCam mounted on the rover’s mast which has the principle microphone. The worldwide crew listened to flights by the tiny Ingenuity helicopter, a sister craft to Perseverance, and heard the rover’s laser zap rocks to check their chemical composition — which made a “clack clack” sound, Maurice informed AFP.
“We had a really localised sound supply, between two and 5 metres (six to 16 metres) from its goal, and we knew precisely when it was going to fireplace,” he mentioned. The examine confirmed for the primary time that the pace of sound is slower on Mars, travelling at 240 metres per second, in comparison with Earth’s 340 metres per second.
This had been anticipated as a result of Mars’ environment is 95 p.c carbon dioxide — in comparison with Earth’s 0.04 p.c — and is about 100 instances thinner, making sound 20 decibels weaker, the examine mentioned.
However the scientists have been stunned when the sound made by the laser took 250 metres a second — 10 metres quicker than anticipated. “I panicked a bit,” Maurice mentioned. “I informed myself that one of many two measurements was mistaken as a result of on Earth you solely have one pace of sound.”
They’d found there are two speeds of sound on the floor of Mars — one for high-pitched sounds just like the zap of the laser, and one other for decrease frequencies just like the whir of the helicopter rotor. Because of this human ears would hear high-pitched sounds barely earlier.
“On Earth, the sounds from an orchestra attain you on the identical pace, whether or not they’re low or excessive. However think about on Mars, in case you are a bit removed from the stage, there shall be an enormous delay,” Maurice mentioned.
“All of those elements would make it tough for 2 individuals to have a dialog solely 5 metres (16 toes) aside”, the French CNRS analysis institute mentioned in a press release. It was in any other case so quiet on Mars that the scientists repeatedly feared one thing was mistaken, the CNRS mentioned, probably scary recollections of two failed earlier makes an attempt in 1999 and 2008 to report sound there.
“There are few pure sound sources apart from the wind,” the scientists mentioned in a press release linked to the examine. The microphones did decide up quite a few “screech” and “clank” sounds because the rover’s steel wheels interacted with rocks, the examine mentioned.