The InSight mission has heard its first meteor impacts on the surface of Mars .
The Mars lander seismometer has detected vibrations from four separate impacts in the past two years, NASA has now announced .
InSight detected seismic waves from four space rocks that crashed into Mars in 2020 and 2021. These not only represent the first impacts detected by the spacecraft’s seismometer since InSight touched down on the Red Planet in 2018 , but also mark the first time seismic and acoustic waves from an impact on Mars have been detected.
The first meteorites we heard from Mars
A new paper published Monday in Nature Geoscience details the impacts, which ranged from 85 to 290 kilometers from InSight ‘s location , a region of Mars called Elysium Planitia.
The first of four confirmed meteorites , the term used for space rocks before they hit the ground, made the most spectacular entry: It entered the Martian atmosphere on September 5, 2021, and exploded into at least three fragments, each one which left a crater.
NASA ‘s Mars Reconnaissance Orbiter then flew over the estimated impact site to confirm the location. The orbiter used its black-and-white context camera to reveal three dark spots on the surface. After locating these spots, the orbiter team used the High Resolution Imaging Science Experiment, or HiRISE, camera to get a color close-up of the craters (the meteoroid could have left additional craters on the surface, but they would be too small to see in HiRISE images).
“After three years of InSight waiting to detect an impact, those craters looked beautiful,” Ingrid Daubar of Brown University, a co-author of the paper and a Mars impact specialist, said in a statement .
After analyzing earlier data, scientists confirmed that three other impacts had occurred on May 27, 2020; February 18, 2021; and August 31, 2021.
should be more common
Researchers have wondered why more meteorite impacts have not been detected on Mars . The Red Planet is adjacent to the solar system’s main asteroid belt, which provides an ample supply of space rocks to mark the planet’s surface. Because Mars ‘ atmosphere is only 1% thicker than Earth’s, more meteoroids pass through it without disintegrating.
InSight ‘s seismometer has detected more than 1,300 earthquakes. Provided by France’s space agency, the National Center for Space Studies, the instrument is so sensitive that it can detect seismic waves thousands of kilometers away. But the event on September 5, 2021, marks the first time an impact has been confirmed as the cause of such waves.
The InSight team suspects that other impacts may have been obscured by wind noise or seasonal changes in the atmosphere. But now that the distinctive seismic signature of a Mars impact has been discovered , scientists hope to find more hidden within nearly four years of InSight data .
The seismic data offers several clues that will help researchers better understand the Red Planet. Most earthquakes are caused by underground rocks cracking from the heat and pressure. Studying how the resulting seismic waves change as they move through different materials gives scientists a way to study the crust, mantle, and core of Mars.
The four confirmed meteor strikes so far have all produced small earthquakes with a magnitude of no more than 2.0. Those smaller earthquakes give scientists just a glimpse of the Martian crust, while seismic signals from larger earthquakes, like the magnitude 5 event that occurred in May 2022, can also reveal details about the Martian mantle and core. planet.