For untrained ears, the one-minute recording is only a vague, scrambled echo. For space specialists, sound is historic. NASA published, Thursday, October 27, the audio recording of an earthquake observed on Mars, on December 24, 2021, after a meteorite struck the surface of the Red Planet.
Our @NASAInSight Mars lander “heard” seismic signals while our Mars Reconnaissance Orbiter captured images of the i… https://t.co/8A9ojw5iUW
The tremors, of magnitude 4, were detected by the Insight probe and its seismometer, placed on Mars almost four years ago, some 3,500 kilometers from the site of the impact. The origin of this Martian tremor was confirmed only in a second time, by the spacecraft called Mars Reconnaissance Orbiter (MRO). In orbit around the planet, it took pictures of the newly formed crater within twenty-four hours of the event.
The image is impressive: blocks of ice were thrown onto the surface, and a crater about 150 meters in diameter and 20 meters deep was dug. The largest ever observed since the commissioning of the MRO orbiter, sixteen years ago. Although meteor impacts on Mars are not uncommon, “we never thought we would see something so big”said Thursday at a press conference Ingrid Daubar, who works on the Insight and MRO missions.
12 meter meteorite
The researchers estimate that the meteorite itself must have been around 12 meters – which on Earth would have led to it disintegrating in the atmosphere. “This is quite simply the biggest meteorite impact on the ground that has been listened to since we have been doing science with seismographs or seismometers”explained to Agence France-Presse Philippe Lognonné, professor of planetology who participated in two studies resulting from these observations, published Thursday in the journal Science.
The information collected should make it possible to refine the knowledge of the interior of Mars, and the history of its formation. The presence of ice, in particular, is “surprising”underlined Ingrid Daubar, also co-author of the two studies. “It’s the hottest spot on Mars, closest to the equator, where we’ve seen ice. »
In addition to the scientific interest of this discovery for the study of the Martian climate, the presence of water at this latitude could prove ” very useful “ for future explorers, said Lori Glaze, director of planetary sciences at NASA. “We would like to land astronauts as close to the equator as possible”, she said, due to warmer temperatures. However, the ice present on site could then be transformed into water or oxygen.
The impact of the meteorite was powerful enough to generate both body waves (propagating to the core) and surface waves (crossing the planet’s crust horizontally), thus allowing the structure to be studied in detail. internal to Mars. The crust on which Insight is located was thus found to be less dense than that traversed from the site of the collision.
As expected, the Insight probe is now operating in slow motion due to dust that has accumulated on its solar panels. Contact will probably be lost by now “about four to eight weeks”said Bruce Banerdt of NASA’s Jet Propulsion Laboratory on Thursday, who thought he was ” sad “ but welcomed the success of the mission, which detected more than 1,300 “Marsquakes”.
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