Due to its fragile atmosphere and proximity to the asteroid belt in our solar system, Mars is significantly more susceptible to being impacted by space rocks than Earth - one of the numerous distinctions between the two planets.
With the help of NASA's robotic InSight lander, scientists are acquiring a greater grasp of this Martian feature. On Monday, scientists detailed how InSight detected seismic and acoustic waves from the impact of four meteorites, and then computed the locations of the craters they left behind - the first time such measurements have been made outside of Earth.
The crater positions were confirmed by data from NASA's Mars Reconnaissance Orbiter in space.
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The InSight mission's lead investigator, planetary geophysicist Bruce Banerdt of NASA's Jet Propulsion Laboratory, stated, "These seismic readings provide us an entirely new instrument for understanding Mars, or any other planet we can place a seismometer on."
The space rocks monitored by InSight, one of which landed in 2020 and the other three in 2021, were projected to weigh up to 440 pounds (200 kilograms), have diameters up to about 20 inches (50 centimeters), and leave craters up to roughly 24 feet (7.2 meters) broad. They landed between 53 and 180 miles (85 to 290 kilometers) away from InSight. One fragment erupted into at least three pieces, each of which carved its own crater.
"We can link a known source type, location, and size to the seismic signal's characteristics. We may utilize this information to better comprehend the full catalog of seismic events recorded by InSight, as well as other planets and moons "Ingrid Daubar, a planetary scientist at Brown University and co-author of the paper published in Nature Geoscience, commented on the findings.
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Now that the seismic signature of such events has been identified, the researchers anticipate to uncover more in InSight's data dating back to 2018.
In 2018, the three-legged InSight — whose acronym stands for Interior Exploration Using Seismic Investigations, Geodesy, and Heat Transport — landed in Elysium Planitia, a huge, relatively flat plain located just north of the Martian equator.
"The moon is also a target for future meteor impact detection," said planetary scientist and principal author of the study Raphael Garcia of the ISAE-SUPAERO institute of aeronautics and space at the University of Toulouse.
"And it's possible that the same sensors will be used, as the spare sensors of InSight are currently being integrated into the Farside Seismic Suite instrument for a 2025 mission to the moon," Garcia added, referring to an instrument that will be placed near the lunar south pole on the side of the moon permanently facing away from Earth.
Mars is approximately twice as likely as Earth to have its atmosphere struck by a meteoroid - the term for a space rock before it hits the surface - as Earth. However, Earth's atmosphere is significantly thicker and shelters the planet.
"Consequently, meteoroids typically fragment and disintegrate in the Earth's atmosphere, creating fireballs that reach the surface to produce craters relatively rarely. Hundreds of impact craters emerge somewhere on the surface of Mars each year "Daubar remarked.
The atmosphere of Mars is barely 1 percent as thick as that of Earth. Between Mars and Jupiter lies the asteroid belt, a rich source of space rocks.
InSight's scientific objectives were to research the interior structure and processes of Mars, in addition to studying seismic activity and meteorite strikes.
InSight's seismometer detected over 1,300 marsquakes, demonstrating that Mars is seismically active. In study published last year, seismic waves discovered by InSight helped comprehend the interior structure of Mars, including the first estimations of its massive liquid metal core size, crust thickness, and mantle composition.
