Study: Frequency of asteroid impacts in the inner solar system constant over the past 600 million years

Using a new crater detection algorithm, which automatically counts impact craters visible from a high-resolution image, a team of planetary researchers from the United States, Australia, the Ivoire et de France analyzed the formation of 521 large impact craters on Mars. .

This image shows a triple crater at Noachis Terra, Mars. The largest crater measures 45 km in diameter and the smallest 28 km. There are also signs of other prominent craters, such as the round sunken surface plates seen at upper right and lower left. This image includes data collected by ESA’s Mars Express using its High Resolution Stereo Camera (HRSC) on August 6, 2020. This image was created using nadir data and color channels from the HRSC. The nadir channel is aligned perpendicular to the surface of Mars, as if looking straight up at the surface. North is on the right. Image credit: ESA / DLR / FU Berlin / CC BY-SA 3.0 IGO.

“Despite previous studies suggesting spikes in the frequency of asteroid collisions, our research showed that they did not vary much over several million years,” said lead author Dr Anthony Lagain, a researcher at the Curtin’s Space Science and Technology Center. University.

“Counting impact craters on a planetary surface was the only way to accurately date geological events, such as canyons, rivers and volcanoes, and to predict when and how large future collisions would be.”

“On Earth, plate tectonic erosion is erasing our planet’s history,” he said.

“The study of planetary bodies in our solar system that still retain their early geological history, such as Mars, helps us understand the evolution of our planet.”

The new crater detection algorithm provided the team with a deep understanding of how impact craters form, including their size and quantity, and the timing and frequency of asteroid collisions that created them.

“Previous studies had suggested that there was a spike in the timing and frequency of asteroid collisions due to debris production,” Dr Lagain said.

“When large bodies collide, they shatter into pieces or debris, which would have an effect on the creation of impact craters.”

“Our study shows that the debris is unlikely to have driven changes in the formation of impact craters on planetary surfaces.”

“Our algorithm could also be adapted to work on other planetary surfaces, including the Moon,” co-author Professor Gretchen Benedix, a researcher at Curtin University’s Space Science and Technology Center, added to Planetary Sciences. Institute and the Department of Earth. and planetary sciences at the Western Australian Museum.

“The formation of thousands of lunar craters can now be automatically dated and their frequency of formation analyzed at higher resolution to study their evolution.”

“This will provide us with valuable information that could have future practical applications in nature conservation and agriculture, such as bushfire detection and land use classification.”

The results were published in the journal Letters on the sciences of the Earth and the planets.

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Antoine Lagain et al. 2022. Did the impact flux of small and large asteroids vary over time on Mars, the Earth and the Moon? Earth and Planetary Science Letters 579:117362; doi: 10.1016/j.epsl.2021.117362

Arline J. Mercier