It is the first time that a mission has collected seismic and acoustic waves from an impact on Mars, and InSight’s first impact detection since landing on the Red Planet in 2018.
Fortunately, InSight was not in the path of these meteoroids, the name for space rocks before they hit the ground. The impacts ranged from 53 to 180 miles (85 to 290 kilometers) away from the stationary lander’s position on Mars’ Elysium Planitia, a smooth plain that is just north of its equator.
A meteoroid hit the Martian atmosphere on September 5, 2021, and then exploded into at least three fragments, each leaving a crater on the surface of the red planet.
The Mars Reconnaissance Orbiter then flew over the site to confirm where the meteorite landed, detecting three dark areas. The orbiter’s color imager, the High Resolution Imaging Science Experiment camera, took detailed close-ups of the craters.
“After three years of InSight waiting to detect an impact, those craters looked beautiful,” study co-author Ingrid Daubar, an assistant professor of earth, environmental and planetary sciences at Brown University in Providence, Rhode Island, said in a statement. .
InSight data also revealed three other similar impacts, one on May 27, 2020, and two additional ones in 2021 on February 18 and August 31.
The agency published a recording of the impact of a Martian meteorite on Monday. During the clip, hear a very sci-fi sounding “bloop” three times as the space rock enters the atmosphere, explodes into pieces, and hits the surface.
In fact, scientists have questioned why more impacts have not been detected on Mars because the planet is located next to our solar system’s main asteroid belt, where many space rocks emerge to hit the Martian surface. The Martian atmosphere is only 1% as thick as Earth’s atmosphere, which means more meteoroids pass through it without disintegrating.
During its stay on Mars, InSight has used its seismometer to detect more than 1,300 marsquakes, which occur when the Martian subsurface cracks due to pressure and heat. The sensitive instrument can detect seismic waves occurring thousands of miles away from InSight’s location, but the September 2021 event is the first time scientists have used waves to confirm an impact.
It is possible that Martian wind noise or seasonal changes in the atmosphere hid additional impacts. Now that researchers understand what the seismic signature of an impact looks like, they hope to find more when they combine InSight data from the last four years.
Impact craters help scientists understand the age of a planet’s surface. The researchers can also determine how many of the craters formed early in the solar system’s tumultuous history.
“Impacts are the clocks of the solar system,” lead author Raphael Garcia, an academic researcher at the Institut Supérieur de l’Aéronautique et de l’Espace in Toulouse, France, said in a statement. “We need to know the impact rate today to estimate the age of different surfaces.”
Studying the InSight data may provide researchers with a way to analyze the path and size of the shock wave that occurs as the meteoroid enters the atmosphere and once it hits the ground.
“We are learning more about the impact process itself,” Garcia said. “Now we can match different crater sizes to specific seismic and acoustic waves.”
The most recent readings have suggested that it could close between next October and January 2023.
Until then, the spacecraft still has a chance to add to its research portfolio and impressive collection of discoveries on Mars.
