Research shows: Sound has two different speeds on Mars

After the Perseverance probe landed on Mars last February, its two microphones started recording, allowing scientists to hear what our "neighboring planet" is "saying" about. .

In a study published in the journal Nature, NASA researchers provided their first analysis of the sounds picked up by the red planet.

The sound revealed unprecedented turbulence, said Sylvestre Maurice, lead author of the study and co-scientific director of SuperCam, a shoebox-sized unit mounted on the mast that holds the main microphone. previously on Mars.

Since landing on Mars more than a year ago, NASA's Perseverance Mars probe has been using microphones to record sounds on the red planet. Those recordings have helped scientists detect that the speed of sound travels on Mars differently than on Earth, according to AFP.

The team used data from the microphone to measure the speed of sound on Mars. Specifically, they measured the time it took for the sound emitted by Perseverance's laser to return to the robot's microphone. This robot shoots lasers at rocks to learn about their composition.

The study confirms for the first time that the speed of sound on Mars travels slower than the speed of sound on Earth, at 240 meters per second - compared with 340 meters per second on Earth.

However, this study shows another problem on Mars, which is that different frequencies of sound travel at different speeds. The sounds of helicopter rotors or low-frequency nature sounds will have the same speed as we just mentioned, but high-frequency sounds, such as the sound from Perseverance's laser, have a higher speed. 250 m/s, up to 10 m/s faster.

"I was a little freaked out," Maurice said. "I told myself that one of the measurements was wrong because on Earth you only have one speed of sound."

The reason for this phenomenon is speculated to be that the atmosphere on Mars is 95% carbon dioxide, carbon dioxide while on Earth it is only 0.04%, and the atmosphere of Mars is also 100 percent thinner than Earth's. times, making the sound 20 decibels weaker, and that's what affects the speed of sound.

They discovered that there are two speeds of sound on the Martian surface: one for high-pitched sounds, like lasers, and one for lower frequencies, like the humming of a helicopter propeller. promoted. The microphone also helps measure the Martian surface temperature around the robot. This is because sound travels at different speeds depending on temperature. By measuring the speed of sound each time Perseverance fired the laser, the researchers were able to calculate the rapid change in temperature. The team intends to continue monitoring and analyzing the Martian acoustics for a year to learn more about changes in different conditions on the red planet, for example during winter or when dust storms occur. appear.

This means that the human ear will hear high-pitched sounds a little earlier.

"On Earth, the sounds of an incoming orchestra will reach your ears at the same speed, whether they're low or high. But imagine on Mars, if you were a little further away from the stage, You will feel the sound reaching your ears is a bit messy, because the high-frequency sound will come first, and the lower-frequency sound will reach your ears later," Maurice said.

Dr Thiery Fouchet from the Paris Observatory, a member of the research team, said the institute, which studies the sound traveling on Mars, and listens to noises such as wind that cause dynamic disturbances, will allow them to fine-tune the digital models. to predict the climate and weather on the red planet.

Sound on Mars also travels shorter distances due to the planet's thin atmosphere. On Earth, sound slows down at a distance of 65 meters, while on Mars, that distance is 4 meters. That means a few meters away is also far if we can talk on this planet. NASA has also released recorded sounds to give people a new perspective on the red planet.

As early as billions of years ago, Mars once had a dense, carbon-rich atmosphere, lakes and oceans made up of liquid water, and possibly even fluffy clouds hovering in the sky. The sun was much smaller than it is now, its light was also weaker, but when solar storms were born, the power was much greater than today.

Mars' size is smaller than Earth's, which means it's also cooling much faster than Earth - Earth's core is still molten - continuously rotating iron core still has strong geomagnetic fields, which can deflect solar wind and do not let us affect us.

After Mars cooled, its core became solid and the planet's magnetic field gradually disappeared. After about 100 million years, the solar wind stripped the atmosphere of Mars. The air pressure on Mars drops to near-vacuum, the surface ocean gradually boils and evaporates, and eventually the whole of Mars becomes extremely dry.

In other words, the solar system is much more habitable today than it was 3 billion years ago. But even so, Mars is still lifeless and lifeless.