Asteroid impacts have a terrible reputation here on Earth — the dinosaurs’ signature public relations victory — but the moon bears the scars of living in our messy neighborhood. That’s because Earth has an arsenal of forces that slowly wear away the craters left behind by impacts. And that’s frustrating for scientists who want to understand better the debris hurtling around our solar system.
So a new study uses the pockmarked lunar surface to trace the history of things smashing into both our moon and Earth, finding signs that our neighborhood got a lot messier about 290 million years ago.
“It’s a cool study that talks about our dynamic solar system and it’s good that it’s out there,” Nicolle Zellner, a physicist at Albion College in Michigan who was not involved in the new research, told Space.com. “It’ll get people thinking and testing it, so that’s exciting.”
Earth and the moon are close enough on the solar system scale that stray asteroids should crash into each at about the same frequency. (Earth may attract a few extra with its stronger gravity, and Earth likely suffers more hits because of its larger surface area — but in terms of impact per square mile, they should be clocking in about the same.)
Scientists have identified only about 180 impact craters here on Earth, as opposed to hundreds of thousands of lunar impact craters. Earth wipes them away with winds and rainfall, oceans, and plate tectonics. “The moon is perfect for studying craters,” Sara Mazrouei, a planetary scientist who led the new research during her doctoral studies at the University of Toronto, told Space.com. “Everything stays there.”