The robot was utilizing a seismometer instrument to calculate ‘marsquakes‘ when it detected the background ‘hum’ of the Red Planet, as per NASA. The probe also observed over 400 quakes, affirming researchers’ theory of Mars having a multitude of seismic activity.
A Song We Cannot Hear
The humming sound is believed to be a mix of the wind above and geological activity underneath the surface, even though the accurate origin is still a mystery. The so-called ‘hum’ cannot be heard by the human ear, as it exists in inaudible frequencies. Mars is also essentially trembling with quakes as it gets colder, InSight’s observations show.
Scientists published their discovery in a few Nature-branded journals on Monday.
“We have discovered Martian infrasound and unexpected similarities between atmospheric turbulence on Earth and Mars,” they wrote in one of the papers.
Infrasound is a noise that cannot be heard by conscious humans. This aspect has been a subject of mystery for a long time, as it has been the invisible cause behind numerous diseases. However, the science around it is still unclear.
Some humans have depicted infrasound as a ‘hum’ that pangs them at the margin of hearing. The sound has been reported more often around particular technologies and in specific regions, such as Windsor, Ontario, even though the precise cause has not been found, apparently.
Scientists have also earlier detected a ‘hum’ to the planet Earth, similar to that identified on Mars. The hum on the Red Planet is one of the few new oddities that InSight researchers are looking to analyze.
“It’s just such a relief to finally be able to stand up and shout, ‘Look at all this great stuff we’re seeing,” Bruce Banerdt, the principal InSight investigator, told National Geographic.
Mysterious Seismic Activity
InSight has been observing a small crater named Elysium Planitia, which is placed on a volcanic plane that’s regularly affected by wind and dust storms. Scientists also collected a set of data about the Martian area’s seismic activity and magnetic field, which ended up being ten times stronger than they initially thought it would be.
The lander captured 174 marsquakes during its first ten months on the Red Planet, the research says. Of them, 24 were fairly powerful with magnitudes around 3-4, and the rest were smaller and of unknown cause. Most of the quakes would not have been a danger to humans on the surface, scientists said in a press conference.
The quakes are being triggered due to the fact that the planet contracts as it cools down, Banerdt explained. However, that is not the cause behind individual ones.
“As the planet cools, it contracts, and then the brittle outer layers have to fracture in order to sort of maintain themselves on the surface,” Banerdt said. “That’s the long-term source of stresses.”
Banerdt’s InSight colleague, Suzanne Smrekar, also pointed to another oddity that might still exist underneath Mars’ surface: “This area still has activity at depth, perhaps including hot magma.”
Simply put, Mars might be hiding lava that scientists did not discover yet, besides humming a song humans cannot hear.