Scientists model Massive Ancient Asteroid Blast

A new study shows an asteroid impact many times more powerful than the one that killed the dinosaurs probably hit the Earth about 3.2 billion years ago - a cataclysmic event that changed the world's tectonic activity, created a vast array of geological features, and contributed to a shift in evolutionary patterns, according to a release from the American Geophysical Union.

The current model shows an asteroid between 37 and 58 kilometers (23 to 36 miles) wide collided with the planet at 20 kilometers per second (12 miles per second). In addition to the massive earthquakes and giant tsunamis that followed, the initial impact shook the planet for a half-hour, suggests the research, which is set to be published in Geochemistry, Geophysics, Geosystems.

The impact may have been one of dozens of huge asteroids scientists think hit the Earth toward the end of the Late Heavy Bombardment period, a period of major strikes that occurred around 3 billion to 4 billion years ago.

"We knew it was big, but we didn't know how big," Donald Lowe, a geologist at Stanford University and a co-author of the study, said of the asteroid.

The study's findings have important implications for understanding the early Earth and how the planet formed. The impact may have disrupted the Earth's crust and the tectonic system that characterized the early planet, leading to the start of more modern plate tectonics, according to the paper's co-authors.

Reconstructing the asteroid's impact could also help scientists better understand the conditions under which early life on the planet evolved, the paper's authors said. Evidence suggests the environmental changes triggered by the impact may have wiped out many microscopic organisms living on the developing planet, allowing other organisms to evolve.

"We are trying to understand the forces that shaped our planet early in its evolution and the environments in which life evolved," Lowe said.