NASA's Insight lander on the Red Planet has "heard" the ominous sounds of marsquakes and other strange, unexplained phenomena.
Insight has an extremely sensitive seismometer, called the Seismic Experiment for Interior Structure (SEIS), which senses vibrations on Mars. The instrument was designed to "listen" for marsquakes, but it can pick up vibrations as subtle as a slight breeze on the Red Planet.
If we were on Mars with our ears to the ground, our ears wouldn't be sensitive enough to detect marsquakes. 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.
Below, listen to two quakes the lander picked up on May 22, 2019 (Sol Martian day 173 of Insight's mission), and July 25, 2019 (Sol 235), respectively.
Even with the audio sped up (to make the pitch higher), the quakes have a deep, ominous sound. For those listening, I recommend headphones (or large, bass-amplifying speakers, if you have them) to really immerse yourself in the unearthly (literally) rumbling of these marsquakes.
"It's been exciting, especially in the beginning, hearing the first vibrations from the lander," Constantinos Charalambous, an InSight science team member at Imperial College London who works with the SP sensors, said in a statement from NASA. "You're imagining what's really happening on Mars as InSight sits on the open landscape."
The sound of the marsquakes suggests that the planet's crust is more similar to the moon's crust than the Earth's, according to the statement. On Earth, cracks in the crust are filled by minerals from flowing water, so vibrations from quakes pass through the material smoothly. On the moon, the drier crust is more fractured, not being filled in by minerals deposited by water, so vibrations are scattered.
On Mars, vibrations traveling through its drier, cratered crust will "ring out" for over a minute, according to the statement, while on Earth these sound waves might dissipate in just a few seconds.
As of now, Insight has heard and recorded over 100 events on Mars. But while scientists are fairly certain that 21 of these events are marsquakes, the remaining could be quakes — or something else. Scientists think these remaining events could also be caused by other sources of vibration on the planet.
Being so sensitive, the SEIS instrument detects just about everything, from the movement of the lander's robotic arm to Martian wind gusts.
The Insight team has noticed that, particularly at night, the instrument picks up strange sounds that they refer to as "dinks and donks," according to the statement. They think that these strange sounds could be caused by the instrument cooling down.
Check out some of these "dinks and donks" for yourself below:
As you can tell, they're extremely prominent and obvious, and almost sound like rain on a tin roof. If you keep listening, you might also hear a strange whistling sound, which the team thinks might be caused by interference in the instrument's electronics, according to the statement.
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