Using a novel crater detection algorithm, which automatically counts the visible impact craters from a high-resolution image, a team of planetary researchers from the United States, Australia, Côte d’Ivoire and France has analyzed the formation of 521 large impact craters on Mars.
This image shows a triple crater in Noachis Terra, Mars. The largest crater measures 45 km across, and the smallest 28 km. There are also signs of other sizeable craters, such as the round patches of sunken surface seen to the top right and bottom left. This image comprises data gathered by ESA’s Mars Express using its High Resolution Stereo Camera (HRSC) on August 6, 2020. This image was created using data from the nadir and color channels of the HRSC. The nadir channel is aligned perpendicular to the surface of Mars, as if looking straight down at the surface. North is to 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 had found they did not vary much at all for many millions of years,” said lead author Dr. Anthony Lagain, a researcher with the Space Science and Technology Centre at Curtin 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 big, future collisions would be.”
“On Earth, the erosion of plate tectonics erases the history of our planet,” he said.
“Studying planetary bodies of our Solar System that still conserve their early geological history, such as Mars, helps us to understand the evolution of our planet.”
The new crater detection algorithm provided the team with a thorough understanding of the formation of impact craters including their size and quantity, and the timing and frequency of the asteroid collisions that made them.
“Past studies had suggested that there was a spike in the timing and frequency of asteroid collisions due to the production of debris,” Dr. Lagain said.
“When big bodies smash into each other, they break into pieces or debris, which is thought to have an effect on the creation of impact craters.”
“Our study shows it is unlikely that debris resulted in any changes to the formation of impact craters on planetary surfaces.”
“Our algorithm could also be adapted to work on other planetary surfaces, including the Moon,” added co-author Professor Gretchen Benedix, a researcher in the Space Science and Technology Centre at Curtin University, the 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 dated automatically, and their formation frequency analysed at a higher resolution to investigate their evolution.”
“This will provide us with valuable information that could have future practical applications in nature preservation and agriculture, such as the detection of bushfires and classifying land use.”
The results were published in the journal Earth and Planetary Science Letters.
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Anthony Lagain et al. 2022. Has the impact flux of small and large asteroids varied through time on Mars, the Earth and the Moon? Earth and Planetary Science Letters 579: 117362; doi: 10.1016/j.epsl.2021.117362
