Much more massive than the Moon, and much closer to the main asteroid belt of the solar system, the red planet is a prime target for large rocks floating around in space. Especially since its atmosphere, a hundred times thinner than that of the Earth, does not allow meteorites to disintegrate.
Until now, we estimated the frequency of meteorite impacts on Mars with models combining observations of craters on the Moon and images of the Martian surface taken by orbiting probes. Then we adjusted these models to the characteristics of the red planet.
The surface of Mars bugged
Except that these estimates seem to be largely underestimated, as demonstrated by the work of an international team, led by researchers from the Zurich Polytechnic School (ETH) and Imperial College London, published in the journal Nature Astronomy.
“It seems more effective to listen to the impacts than to try to see them if we want to understand how often they occur,” said Gareth Collins, co-author of the study and professor at Britain’s Imperial College, in a press release from his institution.
And as a guide, scientists use data from the SEIS seismograph (Seismic Experiment for Internal Structure), deposited by a NASA probe in November 2018, in the Martian plain of Elysium.
The team of researchers thus determined that the planet is struck each year by 280 to 360 meteorites creating craters at least eight meters in diameter. “This rate is five times higher than the number estimated from images taken in orbit alone,” explains Géraldine Zenhäusern, a researcher at ETH, in a press release from her institution.
The planet is struck approximately every month by a meteorite creating a crater at least 30 meters in diameter… This is a rather essential parameter to take into account when planning future missions to Mars.
