A study of different sounds captured by NASA’s Perseverance rover on Mars has revealed that sound waves behave differently on the Red Planet. The study found that sound travels much more slowly on Mars than it travels on Earth. It also behaved in some unexpected ways that could have consequences in setting up communications platforms on Mars when humans colonise it. However, the slowing down of sound waves makes sense as the speed of sound mostly depends on the density of the atmosphere sound waves are travelling. The Martian atmosphere is thinner than Earth’s and hence the movement of sound waves slows down.

Sound typically travels at 343 metres per second on Earth. But they travel much faster, at 1,480 metres per second, in the much denser medium of water, some studies have stated. So, sound waves gain speed as they move into a denser medium and slow down when they move into a thinner medium. Mars has an atmosphere that is over 100 times thinner than that of Earth and is made up of mostly carbon dioxide.

NASA has released an audio ensemble of the sounds captured on Mars. You can listen to them below:

The study of sound waves from Mars also revealed that different sounds behave differently in the Martian atmosphere. Low-pitched sounds travel at about 240 metres per second, while higher-pitched sounds move at 250 metres per second on the Red Planet. This phenomenon has never been experienced before, NASA scientists said. The scientists have published their findings in the Nature journal this week.

“Mars is very quiet because of low atmospheric pressure,” said study co-author Baptiste Chide. “But the pressure changes with the seasons on Mars.” This means Mars could get noisier in the Martian autumn months to come.

The Perseverance rover and its accompanying Ingenuity helicopter were launched in July 2020 and they landed on Mars in February the next year. It is looking for signs of ancient lives on the Red Planet.