The Martian atmosphere is only about 1 per cent as thick as Earth's
NASA's InSight lander has detected a meteoroid impacting the surface of Mars. This is for the first time that the space agency has captured both seismic and acoustic waves from an impact on Mars. Researchers shared findings about the new craters in a study published in Nature Geoscience. InSight landed on the Red Planet in 2018 and since then it is the first time it has experienced waves.
The meteoroid dropped 53 to 180 miles (85 to 290 kilometres) away from InSight's position in Mars' Elysium Planitia, according to the study. It hit the Mars atmosphere on September 5, 2021, and exploded into three shards, each one leaving behind a crater on the Red planet's surface.
The researchers used observations from NASA's Mars Reconnaissance Orbiter in space to confirm the crater locations. "These seismic measurements give us a completely new tool for investigating Mars, or any other planet we can land a seismometer on," planetary geophysicist Bruce Banerdt of NASA's Jet Propulsion Laboratory, the InSight mission's principal investigator, told news agency Reuters.
NASA also released a recording of the Martian meteoroid impact on Monday. In the audio, you hear three "bloops" representing distinct moments of the impact: the meteoroid entering Mars' atmosphere, exploding into pieces, and striking the ground. The peculiar sound is caused by an atmospheric effect that's also been observed in deserts on Earth, where lower-pitched sounds arrive before high-pitched sounds.
A Brown University planetary scientist, Ingrid Daubar, co-author of the study said, "We can connect a known source type, location and size to what the seismic signal looks like. We can apply this information to better understand InSight's entire catalogue of seismic events, and use the results on other planets and moons, too."
The researchers believe that now the seismic signature of such impacts has been discovered they expect to find more contained in InSight's data, going back to 2018, reported Reuters.
The three-legged InSight - its name is short for Interior Exploration Using Seismic Investigations, Geodesy and Heat Transport - landed in 2018 in a vast and relatively flat plain just north of the Martian equator called Elysium Planitia.
"The moon is also a target for future meteor impact detection," said planetary scientist and study lead author Raphael Garcia of the University of Toulouse's ISAE-SUPAERO institute of aeronautics and space.
"And it may be the same sensors will do it, because the spare sensors of InSight are currently integrated in the Farside Seismic Suite instrument for a flight to the moon in 2025," Garcia added, referring to an instrument due to be placed near the lunar south pole on the side of the moon permanently facing away from Earth.
Mars is about twice as likely as Earth to have its atmosphere hit by a meteoroid - the name for a space rock before it strikes the surface. However, Earth has a much thicker atmosphere that protects the planet.
"So meteoroids usually break up and disintegrate in the Earth's atmosphere, forming fireballs that only rarely reach the surface to form a crater. In comparison on Mars, hundreds of impact craters are forming somewhere on the planet's surface every year," Daubar said.
The Martian atmosphere is only about 1 per cent as thick as Earth's. The asteroid belt, an abundant source of space rocks, is located between Mars and Jupiter.
The scientific goals set for InSight ahead of the mission were to investigate the internal structure and processes of Mars, as well as study seismic activity and meteorite impacts.
InSight's seismometer instrument established that Mars is seismically active, detecting more than 1,300 marsquakes. In research published last year, seismic waves detected by InSight helped decipher the internal structure of Mars, including the first estimates of the size of its large liquid metal core, the thickness of its crust, and the nature of its mantle.