Impact craters on the surface of the moon tell the tale of a troubled, violent childhood that may have continued into the moon's adolescence -- a history shared, but obliterated, on Earth.
The findings have implications for understanding how, when and how often life got a toehold on Earth.
"Large impacts in the early solar system could be a factor in keeping life from getting started or evolving rapidly in the early period," Brown University planetary geologist James Head told Discovery News. "Turning it around the other way... so much stuff and larger projectiles moving around the solar system might even increase the possibility of anything that was harboring life to have impacted the Earth as well."
"It makes you think about those early years in the context of what would maybe enhance or deliver life, and what would maybe keep it from gaining a foothold because of the heavy bombardment," Head said.
Working from high-resolution maps of the moon's surface, Head and colleagues homed in on 5,185 craters that are 20 kilometers (12.4 miles) in diameter or larger, an area roughly the size of the city of Atlanta, from among the billions pitting the lunar surface.
The team identified ...