Ya think? Now lets go back to they hit at a steady rate apparently.
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.
“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.”
http://www.sci-news.com/space/asteroid- ... 10485.html