A new study published in Nature reveals that sound on Mars behaves very differently from how it does on Earth. The speed of sound is slower on the Red Planet so sounds tend to fade away faster.

Mars is also dominated by deep silences only broken by howling winds and dust storms. Perseverance has been recording sounds since February 19, 2021, one day after it landed, with all sounds recorded between 20 Hz and 20 kHz making them within the human audible spectrum.

The strangest thing scientists discovered is that the speed of sound is not constant on Mars. High frequencies dim out very quickly while low frequencies tend to last longer.

The reason why sound behaves strangely on Mars is due to the atmosphere being 96% CO2, compared to 0.04% on Earth. This is in addition to the very low atmospheric surface pressure that's 170 times lower than Earth. Even now Perseverance continues recording sounds as it has done for more than a year.

In fact, if all of the Perseverance Mars tracks were combined, the result would last more than five hours, making for quite the historical playlist.