But what’s got scientists buzzing — so much so that NASA has scheduled a press conference on Thursday to highlight the discovery, detailed in two papers published in the journal Science – is that crater-creating impacts have been documented by two NASA spacecraft, an orbiter and a lander. It was a clever demonstration of the combination of scientific resources, one providing an eye on impact events while the other providing an ear.
The result is an unusual wealth of data on the Martian interior, a subject of great interest to planetary scientists who want to understand why this rocky world that was probably hotter and wetter 4 billion years ago has become a freezing desert. without any obvious sign of life.
And it was also an event in the record books: the largest crater-forming impact on one of the solar system’s rocky inner planets ever documented in real time, according to Philippe Lognonné, lead author of one of the papers recently published.
The largest of the new craters is about 150 meters wide and about 21 meters deep, and formed so violently that it threw rocks 40 kilometers (nearly 25 miles) from impact, according to Liliya Posiolova , senior scientist at Malin Space Science Systems, which operates two cameras on NASA Mars reconnaissance orbiter.
The orbiter often sees the results of small impacts, leaving a feature no more than a few meters in diameter. But what scientists from the Posiolova team saw in February was by far the largest crater detected by the orbiter. In fact, it was so large that it almost escaped notice.
“It’s a huge, huge feature. You are trained to see small features. With your eye you look for spots,” Posiolova said.
The crater was spotted on February 11, but scientists knew they had other images of the Martian surface obtained daily, and they went back in time to find the crater’s first appearance.
Posiolova recalled that another spacecraft on Mars, that of NASA InSight Lander, stationed on the surface for four years to monitor seismic activity, had detected a major tremor on Christmas Eve. Suddenly, everything aligned. The first appearance of the crater on the images taken from the orbiter coincided with the seismic signal recorded by the surface instrument.
The seismic data could then be analyzed in the context of distance to impact. This helped refine existing models of the interior of Mars, Lognonné said.
The larger of the two craters was likely caused by an object between 5 and 12 meters in diameter, Posiolova said. Such an object would likely burn up in Earth’s atmosphere if it hit our planet, she said.
The origin of the meteoroids is unknown, but they likely come from the asteroid belt between Mars and Jupiter, she said.
“These impacts are very significant, but we can continue to sleep well on Earth,” Lognonné said. “Our atmosphere protects us.”
