Space: the interior of Mars is revealed thanks to a French seismometer
Audio 01:19
The InSight mission made it possible to analyze seismic data to better understand the internal structure of Mars.
NASA / JPL-Caltech
Text by: RFI Follow
4 min
NASA's Insight mission landed on the surface of Mars at the end of 2018 with a French seismometer, the main instrument and the first interplanetary seismometer on board.
His data earned him the cover of the prestigious journal
Science
this week.
They allow us to better understand what the red planet is made of.
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Listening to the heart of Mars beating is the goal of the mission.
To achieve this, a seismometer was sent to the surface of the red planet.
After more than two years of Martian seismic monitoring, now comes the time for the first lessons.
Philippe Lognonné of the University of Paris is the main investigator.
"
We have earthquakes of magnitude 3.5 to 3.7 which are all around an area called
Cerberus Fossae
(Les Fosses de Cerbères)
," says the researcher.
We know that in
this region, 10 million years ago, there was volcanism.
Surely in this place, Mars cooled because magma came out to the surface.
And today, we see a little this cooling that continues because of this past activity
.
"
A lighter core than expected
A job complicated by the very harsh conditions of Mars, but also its lack of activity, 100 times less than the Earth. The analysis of the seismic waves has nonetheless made it possible to better understand what the core of the red planet looks like.
Raphael Garcia is an engineer at the Higher Institute of Aeronautics and Space (ISAE-Supaero).
He explains what surprised the researchers when analyzing the data: “
This is the first time that we have had an image of the internal structure of a planet close to Earth.
And therefore, the fact that we know the radius of the nucleus makes it possible to estimate its overall density, that is to say roughly, its overall weight.
The big surprise for a big kernel is that suddenly the kernel has to be light, much lighter than we thought.
And this is really a big surprise.
"
The core of Mars lighter than expected.
This partly explains the difference in evolution between the red planet and Earth.
But it now remains to be seen why the Martian core is such as it is.
►Also read
:
“InSight”: a new mission to hear the heart of Mars beating
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