The Insight probe detected in Mars a giant impact left by a meteorite, which would also be the cause of a magnitude 4 marsquake earthquake on December 24.
The meteorite is estimated to have spanned 16 to 39 feet (5 to 12 meters), small enough to have burned up in Earth’s atmosphere, but not in Mars’ thin atmosphere, which is only 1% denser. than that of our planet. The impact, in a region called Amazonis Planitia, blew out a crater about 492 feet (150 meters) wide and 70 feet (21 meters) deep. Some of the ejecta released by the impact flew up to 23 miles (37 kilometers) away.
“It’s unprecedented to find a new impact of this size,” said Ingrid Daubar of Brown University, who leads InSight’s Impact Science Working Group. “It’s an exciting time in geological history, and we got to witness it.”
InSight is studying the crust, mantle and core of the planet. Seismic waves are key to the mission and have revealed the size, depth and composition of the inner layers of Mars. Since landing in November 2018, InSight has detected 1,318 marsquakesincluding several caused by smaller meteoroid impacts.
But the earthquake resulting from last December’s impact was the first observed to have surface waves, a kind of seismic wave that ripples along the top of a planet’s crust. The second of two Science articles related to the large impact describes how scientists use these waves to study the structure of the Martian crust.
“The image of the impact was unlike any I had seen before, with the huge crater, the exposed ice, and the dramatic blast zone preserved in the Martian dust,” said Liliya Posiolova, who leads the Orbital Science and Operations Group at Mars. MSSS. “I couldn’t help but imagine what it must have been like to witness the impact, the atmospheric explosion and the debris ejected miles below.”