Scientists have released two audio clips of seismic activity on the planet after the dome-shaped Seismic Experiment for Interior Structure (SEIS) was set down on its surface late a year ago.
The stationary probe's seismometer, the Seismic Experiment for Interior Structure, is sensitive enough to pick up the most gentle of vibrations.
NASA's InSight lander arrived on Mars in 2018, after which the team spent months carefully surveying its surroundings and deploying a suite of instruments that will peer inside the red planet. But while scientists are fairly certain that 21 of these events are marsquakes, the remaining could be quakes - or something else. Even the recordings taken by Insight are too low to be audible to humans, but by speeding up the audio and lightly processing it, you can listen to marsquakes that Insight captured earlier this year. Like the sounds from the surface, Martian quakes are below the threshold of human hearing. The July 25 quake becomes particularly bass-heavy toward the end of the event.
"[The recordings] suggest that the Martian crust is like a mix of the Earth's crust and the Moon's", NASA's Jet Propulsion Laboratory said. Cracks in Earth's crust seal over time as water fills them with new minerals.
The moon's crust is dry and fractured, which results in scattered sound waves instead of waves traveling in straight, coherent lines. The sound waves can linger for tens of minutes. The surface is cratered like the moon, but its fractures are not as severe, so the seismic waves last for a minute or two.
NASA's InSight's "ear" is so sensitive that it is able to pick up vibrations of a breeze.
SEIS was created to listen for marsquakes, quakes which, much like earthquakes, are the shaking of Mars' surface or interior as a result of the sudden release of energy inside the planet.
On March 6, 2019, a camera on InSight's robotic arm was scanning the surface in front of the lander.
"You're imagining what's really happening on Mars as InSight sits on the open landscape".
The InSight team found that delicate parts inside the seismometer itself were expanding and contracting, causing "dinks and donks" - the team's nickname for odd mechanical sounds - to show up in the samples received and analyzed back on Earth.
The InSight team has a common term for interesting sounds, calling them "dinks and donks".
Listen for these dinks and donks in the set of sounds, below, recorded just after sundown on July 16, 2019.
Clouds drift over the dome-covered seismometer, known as SEIS, belonging to NASA's InSight lander, on Mars. Charalambous and Nobuaki Fuji of Institut de Physique du Globe de Paris released the audio samples.