NASA’s Perseverance spacecraft has found that sound travels on the Red Planet much slower than on Earth and behaves in unexpected ways that affect communication on the planet.
According to Space, sound waves move through the Martian atmosphere more slowly than they do on Earth. This makes sense because the speed of sound depends on the density of the material the sound waves are traveling through (as well as some other variables including temperature).
In Earth’s atmosphere, when the temperature is 20 degrees Celsius, sound travels at 343 meters per second, but in the midst of denser water, it moves at 1,480 meters per second, according to Science Alert.
The Martian atmosphere is 100 times thinner than Earth’s, so sound travels much more slowly, traveling at 240 meters per second, that’s Sense Alert.
new differences
But the Perseverance rover, which landed on the Red Planet in February 2021, has detected some differences about sound on Mars that scientists didn’t expect, according to a new study presented at the 53rd Congress of Lunar and Planetary Sciences earlier this month.
Tests conducted by a team of scientists from Los Alamos National Laboratory, a facility of the US Department of Energy in New Mexico, based on data collected by the rover “Perseverence”, revealed that higher pitched sound travels on the surface of Mars faster than lower pitches, something that has never been seen before. or observed elsewhere.
Why is the transmission of sound different on Mars?
Scientists explain that this strange behavior can be explained by thermal fluctuations in the first 10 kilometers of the Martian atmosphere above the surface of the planet. During the day, when the sun’s rays hit and warm the Martian rock, heat drafts and turbulence move this layer of the planet’s air, also known as the planetary boundary layer.
This changes the behavior of the carbon dioxide molecules. The atmosphere of Mars contains 96% of carbon dioxide, but the atmospheric pressure there is very low. In contrast, Earth’s densest atmosphere contains only 0.041% of carbon dioxide.
Unique Atmospheric Characteristics
“Due to the unique properties of carbon dioxide molecules at low pressures, Mars is the only terrestrial atmosphere in the solar system that experiences a change in the speed of sound in the middle of the audible frequency range, i.e. between 20 Hz and 20,000 Hz,” the researchers wrote in a paper presented at the conference.
When sound frequencies are above 240 Hz, “the collision-activated vibration patterns of the carbon dioxide molecules do not have enough time to relax, or return to their original state,” the researchers said. So sound waves with higher frequencies travel faster than lower frequencies 10 meters per second.
Practically on Mars, higher pitched music can be heard before lower pitched sounds.
The team plans to continue using Perseverance’s SuperCam microphone data to monitor how daily and seasonal changes affect the speed of sound on Mars.
The first audio clip from Mars
The rover landed on Mars in February 2021 after a seven-month spacewalk on a mission to search for evidence of possible past life on the Red Planet.
The massive craft landed in Jezero crater, which scientists believe contained a lake 3.5 billion years ago and which is considered the most dangerous landing site ever because of its terrain.
Two days after its landing, the US space agency published the first audio clip from Mars that the spacecraft managed to capture. The clip was the sound of a light wind.
One of the main objectives of the spacecraft is to collect samples of rocks, dirt and dust from the surface of Mars, which will be returned to Earth in future missions, with the aim of studying it in detail.
So far, Perseverance has collected two samples from the planet’s surface using the Ingenuity helicopter, which operates an aerial scout, to find its worthy targets.
The US space agency notes that since the rover resumed operations on October 25 after a two-week vacation due to an astronomical phenomenon known as the solar conjunction, “Preference” is looking at some of the rocky outcrops in the Jezero crater area.