Mars, by virtue of its weak atmosphere and proximity to the asteroid belt of our solar system, is more vulnerable than Earth.
Mars, by virtue of its fragile atmosphere and proximity to our solar system’s asteroid belt, is more likely than Earth to be hit by space rocks – one of the many differences between the two planetary neighbors.
Scientists are now gaining a fuller understanding of this Martian feature, with the help of NASA’s robotic Insight probe. On Monday, researchers described how InSight detected seismic and sound waves from the impact of four meteorites and then calculated the location of the craters they left — the first such measurements anywhere other than Earth.
The researchers used observations from NASA’s Mars Exploration Orbiter in space to confirm the crater locations.
“These seismic measurements give us an entirely new tool for exploring Mars, or any other planet we can reach with a seismometer,” said planetary geophysicist Bruce Banerdt of NASA’s Jet Propulsion Laboratory, the principal investigator for the Insight mission.
The space rocks tracked by InSight — one landing in 2020 and the other three in 2021 — were relatively modest in size, estimated to weigh about 440 pounds (200 kg), with diameters of about 20 inches (50 cm) and departing up to About 24 feet (7.2 meters). They landed between 53 miles (85 km) and 180 miles (290 km) from the Insight site. One of them exploded into at least three pieces, each causing its own pits to dig out.
“We can correlate the type, location, and size of a known source to what the seismic signal looks like,” Brown said. “We can apply this information to better understand InSight’s entire catalog of seismic events, and use the results on other planets and moons as well.” Undergraduate planetary scientist Ingrid Dubard, co-author of the study published in Nature Geoscience https://www.nature.com/articles/s41561-022-01014-0.
The researchers believe that the seismic signature of such impacts has been discovered, and they expect to find more information from the InSight data, since 2018.
The three-legged InSight rover — its acronym for Inland Exploration Using Seismic Investigations, Geodesy and Thermal Transport — touched down in 2018 on a vast, relatively flat plain north of the Martian equator called Elysium Planitia.
“The moon is also a target for future meteorite impact detection,” said planetary scientist and study lead author Rafael Garcia of the ISAE-SUPAERO Institute of Aeronautics and Astronautics at the University of Toulouse.
“And it may be the same sensors that will do that, because InSight’s backup sensors are currently built into the Farside Seismic Suite instrument for a trip to the Moon in 2025,” Garcia added, referring to an instrument slated to be placed near the lunar south pole on the side of the moon facing visibly. Permanently off the ground.
Mars’ atmosphere is more than twice as likely to be hit by a meteorite as Earth is – the name given to a space rock before it hits the surface. However, the Earth’s atmosphere is much thicker than what protects the planet.
“Meteorites typically disintegrate and disintegrate in Earth’s atmosphere, forming fireballs that rarely reach the surface to form a crater. Compared to Mars, hundreds of impact craters form somewhere on the planet’s surface each year,” Daubar said.
Mars’ atmosphere is only 1% as thick as Earth’s. The asteroid belt, an abundant source of space rock, lies between Mars and Jupiter.
InSight’s specific science goals prior to the mission were to investigate the internal structure and processes of Mars, as well as study seismic activity and meteorite impacts.
InSight’s seismograph has proven that Mars is seismically active, detecting more than 1,300 swamps. In a paper published last year, seismic waves detected by InSight helped decipher the internal structure of Mars, including first estimates of the size of its massive liquid metal core, the thickness of its crust, and the nature of its atmosphere.
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