Since arriving on Mars in November 2018, NASA’s InSight lander has continued to probe the interior of the planet for signs of seismic activity. To do this, he used a very sensitive seismometer as well as a whole set of instruments intended to reveal the secrets of the geology of the Red Planet.
Recently, researchers from the US space agency published 5 articles in scientific journals Nature Geoscience and Nature Communications regarding the results achieved so far by InSight. Among the results is the detection of what could be called a buzzing sound, quite different from the tremors that scientists have been able to record.
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So far, the researchers behind InSight still have no explanation as to the origin of the mysterious buzz. However, some avenues can be envisaged.
Still mysterious tremors
To date, InSight has recorded almost 450 earthquakes on the planet Mars. However, researchers are still unsure of the exact sources. If we take the case of Earth, it is the tectonic plates interacting with each other that create earthquakes. Mars for its part does not have global tectonic plates. Scientists are trying to find other explanations.
As far as we know, two specific events detected by the lander could help scientists find answers. These two earthquakes had a magnitude between three and four, which made it possible to trace their origin. Apparently, the two tremors are believed to originate from deep cuts at the surface level, in an area known as Cerberus Fossae, formed about 10 million years ago.
According to the researchers’ explanations, lava flows and streams of water once came out of the cracks of Cerberus Fossae. It is thus possible that certain fluids are still present in the depths. If so, pockets of magma that cool and contract, or the movement of magma or water could be the cause of the two earthquakes.
What could be the source of the buzz?
Among the seismic activities detected by InSight, one of the signals seems to be buzzing continuously and researchers do not yet know the source. On Earth, you can also record background noise of the same type, but it is caused by movements of the ocean and by the noise made by the sea in contact with the coast. On Mars, the detected signal has a frequency of 2.4 Hz, which is much higher than what we hear on Earth.
According to the analyzes carried out by the researchers, the hum of the planet Mars is not related to the winds which circulate there, but seems to be reinforced each time there is an earthquake in the distance. One of the hypotheses put forward is that the noise in question is linked to the geology of the soil under InSight. The latter’s landing site is in fact an old crater filled with dust and sand which could “ring” by trapping the waves emitted by the tremors. However, it seems that the whole is not excited by strong winds and the basin formed is too small to generate such a buzz.
With the many measurements that will still be made in the future, scientists will eventually be able to understand where the mysterious buzz comes from. Thanks to InSight, we can also learn more about the source of the Red Planet earthquakes.
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