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Christmas came a little early for NASA’s InSight mission last December when it detected a large earthquake on Mars.
Now scientists know what causes the rumble of the red planet. The meteoroid crashed into Mars 2,174 miles (3,500 kilometers) from the lander, creating a new impact crater on the Martian surface.
Earth moved beneath InSight on December 24, 2021, when a magnitude 4 earthquake was recorded. Before and after photos taken from above by the Mars Reconnaissance Orbiter, which has been orbiting Mars since 2006, revealed a new crater last February.
When scientists connected the dots from both missions, they realized it was one of the largest meteoroid impacts on Mars since NASA began exploring the red planet. Images from the orbiter’s two cameras showed the crater’s blast zone, which allowed scientists to compare it to the epicenter of the earthquake detected by InSight.
The journal Science published two new studies that explain this influence and its effects Thursday.
The space rock also discovered boulder-sized chunks of ice as it crashed into Mars. They were found buried near the Martian equator, warmer than any ice ever discovered on the planet.
“The image of the impact was unlike anything I’ve seen before, with a large crater, exposed ice and a dramatic blast zone preserved in Martian dust,” said Liliya Posiolova, head of orbital science operations at Malin Space Science. Systems in San Diego, in a comment.
“I couldn’t help but imagine what it must have been like to witness the impact, the atmospheric explosion and the debris being thrown for miles.”
Studying the ice uncovered by the impact will help scientists better understand past climate conditions on Mars, as well as how and when the ice was deposited and buried.
Researchers estimated that the space rock’s namesake meteoroid was about 16 to 39 feet (5 to 12 meters) before it hit the ground. While this is small enough to burn in Earth’s atmosphere, the same cannot be said for Mars, which has a thin atmosphere only 1% as dense as Earth’s.
When the meteoroid hit Mars, it created a crater 492 feet (150 meters) wide and 70 feet (21 meters) deep in the Amazonis Planitia region of the planet. Some of the material that erupted from the crater fell 23 miles (37 kilometers). Teams at NASA also recorded the impact, so you can hear what the space rock sounded like when it hit Mars.
Images taken by the orbiter, along with seismic data recorded by InSight, make the impact one of the largest craters ever observed to form in the solar system. Mars is full of giant craters, but they are older than any mission to explore the red planet.
“Finding a new impact of this size is unprecedented,” said Ingrid Daubar, InSight’s head of impact sciences at Brown University in Providence, Rhode Island. “This is an exciting moment in geologic history, and we need to witness it.”
If such an earthquake were to occur on Earth, “it would be big enough to be felt, but not big enough to cause a ton of damage,” Daubar said. According to him, about a thousand earthquakes of this size occur on Earth every year, but Mars is less active than our planet, so this was “quite big” for the red planet.
The shock wave from the impact also created surface waves, or seismic waves that travel through the upper part of the Martian crust. InSight’s data from the event will help scientists study the planet’s crust and learn more about its structure.
Studying craters and the rate at which they form can help scientists determine the geologic timeline of Mars. Impact craters also excavate material and bring it to the icy surface exposed by the December 24 strike.
The ice beneath the Martian surface could be used by future astronauts to produce drinking water, rocket fuel, and even grow crops and plants. Finding ice so close to the equator, the hottest region on Mars, could make it an ideal location for manned missions to the red planet.
Earlier, InSight has “heard” and detected space rocks hitting Mars, but December’s impact was the biggest. Since landing in 2018, the mission has revealed new details about the crust, mantle and core of Mars and detected 1,318 earthquakes.
Unfortunately, InSight’s mission is running out of time. Increasing amounts of dust have settled on the lander’s solar panels, exacerbated only by a continent-wide dust storm detected on Mars in September, and its power levels continue to drop.
Fortunately, the storm did not pass directly over InSight—otherwise, the darkness of the storm would have ended the mission. But the weather event kicked up a lot of dust into the atmosphere, which reduced the amount of sunlight reaching InSight’s solar panels, said Bruce Banerdt, InSight’s principal investigator at NASA’s Jet Propulsion Laboratory in Pasadena, California.
Mission scientists estimate that InSight will shut down within the next six weeks, ending a promising mission to explore the interior of Mars.
“Over the last four years, we have gone well beyond the intended duration of the mission, which is two years,” Banerdt said. “Even now that we’re done, we’re still getting these amazing new results.”
