NASA’s InSight lander arrived on Mars last November, to study the planet’s insides and observe any seismic activity. Using a specialized seismometer called SEIS, the lander first detected shakes on April 6.
InSight has now measured more than 100 rumblings since then, including 21 that are considered actual quakes.
Listen for yourself: The two audio tracks NASA uploaded are from marsquakes measured on May 22 and July 25 this year, with magnitudes of 3.7 and 3.3, respectively. These SEIS readings are far below the normal range of human hearing, so they’ve been sped up and processed into higher frequencies.
Why it matters: The sounds are fun, but they also yield a few useful bits of insight. When quakes are produced on Earth, the resulting vibrations are able to travel uninterrupted and pass in just a matter of seconds, because any fractures in the crust end up becoming filled up over time by minerals carried by water.
On the moon however, the lack of liquid water in the crust means fractures are permanent, and so moonquakes create an intense scattering of vibrations. The sound waves can linger for tens of minutes.
Mars is something of a mix of the two. The surface is cratered like the moon, but its fractures are not as severe, so the seismic waves last for a minute or two. It’s more evidence of how much Mars and Earth have in common, and yet how distinct they’ve become over billions of years.
How's InSight?: The lander's heat probe has been digging into into the Martian soil since February, but appears to be stuck 14 inches down. NASA's trying to leverage InSight's robotic arm in a "pinning" maneuver that might give it a bit of weight to continue its 16-foot dig into the ground.