Earthquakes on Mars reveal that the ‘red planet’ receives hundreds of meteorite impacts every year

The planet Marte is hit by hundreds of meteorites every year, five times more than previously thought, according to a study published Friday based on seismic recordings.

Until now, The frequency of these impacts had been estimated with models that combined the observation of meteorite craters on the Moon with images of the surface of Mars taken by orbiting probes.

These models were then adjusted to the characteristics of the red planet, which is much larger than the Moon.

Mars receives many more meteorites because it is closer to the main asteroid belt of the Solar System. Furthermore, it has almost no atmosphere – it is one hundred times thinner than Earth’s – so it cannot count on this protective shield to disintegrate some of the meteorites.

“It seems more effective to listen to the impacts than to try to see them if we want to understand how often they occur“Professor Gareth Collins of British Imperial College, co-author of the study published Friday in Nature Astronomy, said in a statement.

The study was carried out with an international team, led by researchers from the Swiss Federal Institute of Technology Zurich (ETH) and Imperial College London.

The records were made with the SEIS seismograph (Seismic Experiment for Interior Structure), an instrument carried out under the supervision of the French space agency (CNES).

A NASA spacecraft called InSight dropped the seismometer in November 2018 on Elysium Planitia, a vast, flat region on Mars, allowing scientists to hear what’s happening on the planet for the first time.

Hear every impact

The initial objective was to measure the internal activity of Mars and possible seismic phenomena.

These data allowed the team of researchers to determine that Every year the planet receives the impact of between 280 and 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 Geraldine Zenhäusern, a researcher at ETH, in a statement from her institution.

Identifying small meteorite craters from an orbiting spacecraft is even more difficult on Mars because sandstorms are common.

“The new craters are visible on flat, dusty terrain, but this type of terrain only covers half of the planet,” says Zenhäusern. That is why the advantage of the seismograph was “being able to hear each impact within the range of the probe.”

The scientific team identified a particular type of acoustic waves that spread on the surface of Mars when a meteorite falls.

The seismograph detects the so-called Marsquake-VF (High Frequency Mars Earthquakes) which allow the diameter of a crater and its distance from the probe to be estimated.

The number of craters created in a year within a given radius around the probe is then calculated and that figure is extrapolated to the scale of the planet.

“This is the first study of its kind to use seismological data to determine the frequency of meteorite impacts on the surface of Mars,” says ETH professor Domenico Giardini.

Some data, which according to him, “must be taken into account in the planning of future missions to Mars”.

Approximately every month a meteorite hits Mars and creates a crater at least 30 meters in diameter.