Two massive meteorite impacts were recorded on Mars by NASA’s international teams of InSight and Mars Reconnaissance Orbiter missions. One of them, 150 meters in diameter, is the largest ever detected on a planet. The Toulouse Space Center (CNES) is associated with the discovery, which will enrich knowledge of the constitution and inner workings of Mars.
Two impacts to advance knowledge. Thanks to the work done by the international teams of the InSight and Mars Reconnaissance Orbiter (MRO) missions, the planet Mars reveals a little more of its deepest secrets. Two studies revealed on October 27, 2022 by NASA – the American space agency – and published in the journal Science will provide a better understanding of the internal structure of the planet Mars and the movements related to atmospheric shock waves.
Our @NASAInSight The Mars lander “heard” the seismic signals while our Mars Reconnaissance Orbiter captured images of the impact crater created by this Martian meteorite. To make the sounds audible, the data was accelerated 100 times. Listens: https://t.co/X00C5ca2NQ
–NASA (@NASA) October 27, 2022
At the origin of this work, two huge meteorite impacts on the surface of Mars. The former left a footprint of 130 meters in diameter on the surface of Mars. The second, with its 150 meters in diameter, becomes the largest crater recorded in recent centuries on a telluric planet. They were first spotted by the MRO spacecraft on a mission around Mars for 16 years. Thinking these were recent impacts, the teams working on MRO then asked those on the InSight mission to look for a clue in their data.
“Waves that have crossed the planet”
Several kilometers away, the shock waves of the two impacts were in fact recorded by the SEIS seismometer, designed by the CNES. At the Toulouse Space Center, SISMOC operators receive data from the seismometer, process it and redistribute it to scientists. They manage to find the events and date them to September 18 and December 24, 2021.
“This data is very important because these powerful impacts have generated waves that have passed through the planet to its core. Until now we only had surface wave recordings. We are very happy because we are doing everything to keep the instrument operational and not. miss no earthquake, “explains Charles Yana, SEIS-InSight project manager at CNES. Since landing on November 26, 2018, the InSight mission has aimed to understand the inner workings of the planet Mars. It has officially processed the data of 5 meteorite impacts, others are being analyzed.
Understand how Mars evolved
The combination of shock wave record data with the impact localization of very high resolution images makes this work unique. Scientists estimated the mass of the largest meteorite to be between 250 and 650 tons for an impact velocity of 7.5 km / s.
My environment is peaceful and quiet, allowing me to pick up the vibrations from the depths of Mars. But at first, I also captured seismic waves from a more dramatic source: several meteoroids hitting miles away.
–NASA InSight (@NASAInSight) September 19, 2022
“This is the largest impact on a telluric planet ever documented in the last 200 years. On Earth, the largest crater sighted in the early 19th centuryAnd century and located in Saudi Arabia has a diameter of 120 meters. For 50 years we have never recorded an impact on the ground exceeding 10 meters. The Earth’s atmospheric shield is very effective, most meteorites explode at an altitude of 20 kilometers “, explains Philippe Lognonné, second author of one of the articles published in Science. Scientific director of the SEIS seismometer, the geophysicist of the Physics Institute of Land of Paris and the University of Paris Cité, emphasizes the interest of these discoveries.
“We are like facing the transmission of a film of which we see the images of the MRO satellite but without the sound. The sound comes later, without an image, thanks to the SEIS seismometer and there we can understand the film. Seismologists know exactly where the source, they can really measure the wave propagation time.The data confirm our models on the crust of Mars and we will be able to work to better understand what is happening closer to the core.Like other Martian missions (Curiosity, Perseverance), let’s try to understand how Mars formed, how it evolved “.