Mars gets hit by hundreds of basketball-sized space rocks every year | CNN

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Hundreds of basketball-sized space rocks slam into Mars every year, leaving impact craters and rumbling on the Red Planet, according to new research.

Mission planners could use the revelations, captured in data collected by a now-retired NASA mission, in determining where to land future robotic missions and astronaut crews on the red planet.

NASA’s InSight mission ended when the stationary lander lost the battle against a buildup of Martian dust on its solar panels in December 2022. However, the wealth of data collected by the spacecraft continues to yield new research results.

The lander brought the first seismometer to Mars. The sensitive instrument was able to detect seismic waves thousands of miles away from InSight’s location in Elysium Planitia, a smooth plain just north of the planet’s equator.

During its time on Mars, InSight used its seismometer to detect more than 1,300 Marsquakes, which occur when the Martian subsurface cracks due to pressure and heat.

But InSight also captured evidence of meteorites hitting Mars.

Meteoroids are space rocks that have broken off from larger rocky bodies and range in size from dust particles to small asteroids, according to NASA. They are known as meteoroids while they are still in space, and are called meteors as they streak through the atmosphere of Earth or other planets.

Scientists have wondered why more impacts haven’t been detected on Mars, since the planet is located next to our solar system’s main asteroid belt, where many space rocks emerge to hit the Martian surface. Mars’ atmosphere is only 1% the thickness of Earth’s atmosphere, meaning more meteorites shoot through it without breaking up.

On September 5, 2021, a meteorite slammed into the Martian atmosphere and exploded into at least three fragments, each leaving a crater on the Red Planet’s surface. And that was just the beginning.

Since 2021, researchers have been studying InSight data and finding that space rocks are bombarding Mars more often than previously thought, as much as two to 10 times higher than previous estimates, according to a new study published Friday in the journal Science Advances.

“It is possible that Mars is more geologically active than we thought, which has implications for the age and evolution of the Earth’s surface,” lead study author Ingrid Daubar, associate professor of earth, environmental and planetary sciences at Brown University, said in a statement. . “Our results are based on a small number of available examples, but the estimate of the current impact rate suggests that the planet is being hit much more often than we can see from imaging alone.”

The team identified eight new impact craters made by meteorites using InSight data that had previously been spotted by orbiters orbiting the planet. Six of the craters were near InSight’s landing site, and two of the distant impacts were among the largest ever detected by scientists observing the Red Planet, the study said.

Each of the two large impacts left craters the size of football fields, 97 days apart.

“We would expect to have an impact of this magnitude maybe once every few decades, maybe even once in a lifetime, but here we have two that are just over 90 days apart,” Daubar said. “It could just be a crazy coincidence, but the chances of it just coinciding are very, very slim. What’s more likely is that the two big impacts are related, or that the impact speed for Mars is much higher than we thought.”

The team compared the data collected by InSight with that from NASA’s Mars Reconnaissance Orbiter to determine where the impacts occurred. Before and after images allowed the team to confirm eight of the craters. It’s possible that InSight detected more impacts during its mission, and the team plans to continue combing through the data to look for evidence of fresh craters in orbit.

“Planetary impacts are happening all the time throughout the solar system,” Daubar said. “We’re interested in studying that on Mars because then we can compare and contrast what’s happening on Mars with what’s happening on Earth. This is important for understanding our solar system, what’s in it, and what the impactor population looks like in our solar system — both as a hazard to Earth and historically to other planets.”

A companion paper, published Friday in the journal Nature Communications, also examined seismic events recorded by InSight to determine that basketball-sized meteoroids crash onto Mars almost daily.

The study found that between 280 and 360 meteorites hit the Red Planet each year, creating impact craters larger than 26 feet (8 meters) across. Larger craters, spanning 98 feet (30 meters), occur about once a month, the study authors said.

“This rate was approximately five times higher than the number estimated from orbital images alone,” said study co-lead author Dr. Géraldine Zenhäusern, professor of seismology and geodynamics at Switzerland’s ETH Zurich, said in a statement. “In line with orbital imaging, our findings demonstrate that seismology is an excellent tool for measuring impact rates.”

By analyzing seismic events traced to meteoroids, the team identified about 80 Marsquakes recorded by InSight that may have been caused by impacts. The Martian earthquakes caused by meteoroid impacts occur more frequently and last shorter than other Marsquakes caused by subsurface activity.

“While new craters are best seen on flat, dusty terrain where they really stand out, this type of terrain covers less than half of the Martian surface,” Zenhäusern said. “However, the sensitive InSight seismometer was able to hear every single impact within range of the landers.”

According to the researchers, seismic data from the tiniest ground motions on Mars could provide the most direct way to understand exactly how many impacts occur on Mars.

“By using seismic data to better understand how often meteorites strike Mars and how these impacts alter the surface, we can begin to piece together a timeline of the red planet’s geological history and evolution,” said co-lead study author Dr. Natalia Wojcicka, research associate in the Department of Earth Sciences and Engineering at Imperial College London, said in a statement. “You could think of it as a kind of ‘cosmic clock’ that helps us date the surfaces of Mars, and perhaps later other planets in the solar system.”