Several days ago, a gust of wind swept across Elysium Planitia on the surface of Mars. This has happened uncountable times over the eons, but never before was a robot on hand to record the sound of that wind. Now, NASA’s InSight lander is sitting on Elysium Planitia with a suite of instruments designed to study the geology of Mars. It turns out, they can also sample the sound of Martian wind for the first time ever.
The new recording comes from two of InSights sensors, neither one of which was intended for this particular use. The lander’s seismometer is currently stowed while NASA plans the delicate process of setting it on the ground and shielding it from the wind. In the meantime, NASA managed to use the seismometer to measure the vibrations from the nearby solar panel array. This sound is at the very bottom range of human hearing, but you’ll be able to hear it if you’ve got a good set of speaker or headphones. To help you make it out, the video below includes the original recording and a version shifted up two octaves.
Elsewhere on InSight, there’s the air pressure sensor. NASA used this instrument to record vibrations in the air directly, which is closer to what we on Earth would think of as sound. However, it’s nowhere close to the gusty noises you’ve heard on Earth. It’s eerie and, well, alien.
NASA had to make some tweaks to the original air pressure recording to bring it into the realm of human hearing. Mars’ atmosphere is mainly carbon dioxide, and it’s much thinner than Earth’s atmosphere. The blowing wind on Mars doesn’t have enough energy to produce eddies on the millimeter scale like on Earth. Currents on Mars tend to fall apart around a centimeter, which results in a low rumble that’s difficult to hear. Thus, the pitch of the gusting was far too low to hear unaided despite the wind blowing at 10 to 15 miles per hour. The NASA team sped up the recording by 100 times to make it audible. The final 29-second recording came from about 48 minutes of audio. That doesn’t mean you’d never be able to hear the wind while standing on Mars. Once it hit about 30 miles per hour, you’d be able to hear a low hum. Of course, you’d have bigger problems if you were in a position to hear the Martian wind blow.
In InSight lander made history recording the sounds of Mars, but that’s not going to be the only “first” on the mission. InSight’s true goal is to study the internal structure of Mars like never before. The seismometer that monitored the vibration of solar panels will eventually record Marsquakes, and a temperature probe will drive itself several meters deep to take the planet’s temperature. The first science operations should take place in a few months.