Your brain can already picture what Mars looks like.you might come up with an image barren landscape Boulders and pebbles scattered under a reddish-brown sky. It’s familiar by now.
But what about our other senses?
Thanks to recent work by scientists, we now have a better understanding of how to do it hear red planet. The Perseverance rover uses one microphone on its SuperCam and a second microphone mounted on its chassis to record.A team then analyzed the recordings and released The result is nature.
the silence of the birds
One thing about Mars is its silence. Mars is really quiet.
The red planet’s silence stems from the mass of its atmosphere. To understand how the atmosphere affects sound, we need to review how sound waves travel.
Sound is actually a pressure wave. Unlike light, sound waves must travel through a medium. They cause the atoms and molecules of the medium to vibrate back and forth as the sound passes through. This compresses the media.
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We know a few things about the atmosphere of Mars compared to the atmosphere on Earth. For one, it’s thin — just over half the pressure of Earth’s atmosphere at sea level. But it’s also colder and consists mostly of carbon dioxide, the main component of Earth’s atmosphere.
As a sound wave travels, it needs to shake molecules in the atmosphere to keep itself running. Because of Mars’ colder atmosphere, these molecules have been slower to move. Because the atmosphere is less dense, there are fewer molecules available to collide and transmit sound waves. And because carbon dioxide molecules are heavier than nitrogen or oxygen molecules, the atmosphere is heavy. All of these factors work together to make the sound decay faster with distance. On Earth, sound decays at a distance of about 65 meters. On Mars, they fall after only eight meters.
Ambience also affects the pitch of the sound.Certain high-pitched noises, such as chirps bird almost completely disappear. This is mainly due to the special properties of a carbon dioxide-rich atmosphere: it attenuates or absorbs higher-pitched sounds.
When Perseverance’s mic was listening, they didn’t hear much—just a little Martian wind.
However, when small originality The helicopter took off, and Perseverance could hear the whistling of its wings against the air. Pulses from the rover’s gas dusting tool were also recorded, which removes dust and debris once the rover has inspected them. These sounds were useful for analysis because the team knew exactly when they were made and how far away they were.
Their analysis led to some surprises.
At first, the team thought something was wrong—the laser was making sounds much faster than expected. Is something broken?
The real reason surprised everyone – sound travels at different speeds on Mars. High frequency sounds travel faster than low frequency sounds. This means that the laser’s high-pitched waves travel faster than the helicopter’s bass waves.
On Earth, sound travels at the same speed. On Mars, the speed difference between these sounds is about ten meters per second. Carbon dioxide was previously thought to affect the speed of sound, but it was surprising to actually hear its effect.
These unique properties of the Martian atmosphere would make it sound unfamiliar. Imagine sitting in a row a little further from the stage and listening to a concert on Mars. The timing of the music doesn’t sound right. The high notes of the flute and harp will reach your ears before the notes of the tuba and cello. Also, flutes and harps will sound much quieter than they should be, since those highs are more attenuated than the lows.
In very cheap seats away from the orchestra, you have to use your imagination because you may not hear anything at all.