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Christmas came a little early for NASA’s InSight mission last December, when the lander detected a massive earthquake on Mars.
Now, scientists know what caused the red planet to rumble. A meteoroid hit Mars 2,174 miles (3,500 kilometers) from Earth and created a new impact crater on the Martian surface.
The Earth literally moved beneath InSight on December 24, 2021, when the lander recorded a March of 4 degrees. Pictures taken from above by the Mars Reconnaissance Orbiter, which has been circling Mars since 2006, showed a new crater last February.
When scientists connected the dots from the two missions, they realized that it was one of the largest meteoroid strikes on Mars since NASA began studying the red planet. Images from the orbiter’s two cameras showed the crater’s blast zone, which scientists were able to compare with the epicenter of the earthquake detected by InSight.
The journal Science published two new studies Thursday that describe the impact and implications.
The space rock also revealed boulder-sized chunks of ice when it crashed into Mars. They were found buried closer to Mars’ warm equator than any ice ever detected on the planet.
“The image of the impact was unlike anything I’ve seen before, with a massive crater, exposed ice and a massive blast zone buried in Martian dust,” said Liliya Posiololova, director of orbital science operations at Malin Space Science. San Diego Systems, in a statement.
“I couldn’t help but see what the impact must have been like, the atmospheric blast and the debris thrown miles away.”
Studying the ice exposed by the impact will help scientists better understand the previous climate conditions on Mars, as well as how and when the ice was deposited and buried.
The researchers estimated that the meteoroid, the name given to a space rock before it hit Earth, was about 16 to 39 feet (5 to 12 meters). While this would be 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 in the Amazonis Planitia region of the planet that was 492 feet (150 meters) wide and 70 feet (21 meters) deep. Some of the material ejected from the crater landed 23 miles (37 kilometers) away. NASA teams also recorded the sound of the impact to hear what it sounds like when a space rock hits Mars.
Images taken by the orbiter, along with seismic data recorded by InSight, make it one of the largest craters in our solar system when the impact occurred. Mars is littered with incredible craters, but they are much older than any mission to explore the red planet.
“Finding a new impact of this size is unprecedented,” InSight’s impact science manager, InSight, at Brown University in Providence, Rhode Island, said in a statement. “This is an exciting moment in geological history, and we must witness it.”
If an earthquake like this had occurred on Earth, “it would be enough to be felt, but not to cause much damage”, said Daubar. About a thousand earthquakes of this size occur on Earth each year, but Mars is less active than our own planet, so it was “pretty big” for the red planet, he said.
The earthquake from the impact also created surface waves, or seismic waves that moved along the top of the Martian crust. Data from the InSight event will help scientists study the planet’s crust and learn more about its structure.
Studying the craters and their rate of formation can help scientists determine the geological timeline of Mars. Impact craters also excavate material and bring it to the surface, like the ice exposed by the December 24th strike.
Martian surface ice could also be used by future astronauts for drinking water, rocket propellant, and growing crops and plants. And the discovery of ice so close to the equator, the hottest region on Mars, could be an ideal place for crewed missions to land on the red planet.
InSight has previously “heard” and detected space rocks hitting Mars, but the impact in December was the biggest. Since landing in 2018, the mission has revealed new details about Mars’ crust, mantle and core and detected 1,318 craters.
Unfortunately, InSight’s mission is running out of time. An ever-increasing amount of dust has settled on the lander’s solar panels, exacerbated by a continent-sized 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 end the mission. But the weather event has thrown a lot of dust into the atmosphere, reducing the amount of sunlight reaching InSight’s solar panels, said Bruce Banerdt, InSight principal investigator at NASA’s Jet Propulsion Laboratory in Pasadena, California.
Mission scientists believe InSight will shut down in the next six weeks, ending a promising mission to unlock the interior of Mars.
“In the last four years we have gone well beyond the planned life of the mission, which was two years,” Banerdt said. “And even now as we’re wrapping it up, we’re getting these amazing new results.”