For billions of years, our planet has been bombarded by asteroids, but most traces of these violent impacts have been erased by time. While the Moon’s surface is scarred with craters, Earth’s active geology makes such discoveries rare. Now, a team of scientists has uncovered a crater in Western Australia that pushes back the record for the oldest known impact by an astonishing 1.3 billion years.
Located in the Pilbara Craton—a region containing some of the planet’s most ancient exposed rocks—this newly identified crater dates back 3.5 billion years. Previously, the title of Earth’s oldest known impact site belonged to the 2.2-billion-year-old Yarrabubba crater, also in Western Australia.
A Devastating Impact That Shaped Earth’s Evolution
Based on the geological evidence, researchers estimate that a massive space rock slammed into the region at speeds of around 36,000 km/h (22,370 mph), leaving behind a crater spanning roughly 100 km (61 miles). The sheer force of this collision would have scattered debris worldwide, significantly influencing the planet’s environment.
“This impact predates any other known terrestrial crater by more than a billion years,” said Professor Tim Johnson from Curtin University, a co-lead of the study. “Large impacts were far more common in the early Solar System, but until now, evidence of these ancient craters was missing from Earth’s geological record.”
One of the key indicators of this impact event was the discovery of shatter cones—distinctive rock formations that only form under extreme pressure. Similar evidence, such as microscopic impact spherules, had been found in the region in 2023, hinting at multiple ancient collisions.
How Did This Impact Shape Early Earth?
Beyond confirming the violent history of asteroid impacts, this discovery sheds new light on how these cosmic events may have influenced Earth’s development. Some researchers suggest that these impacts created conditions favorable for microbial life, such as hydrothermal pools.
“Finding more craters from this era could help explain how life emerged,” said Professor Chris Kirkland, another co-lead author of the study. “These impacts could have provided the right environmental conditions, including hot water systems, which are known to support microbial life today.”
The study also presents groundbreaking insights into the formation of Earth’s crust. The immense energy released by this event may have triggered geological processes such as crust recycling and magma movement, contributing to the formation of cratons—the stable landmasses that eventually became continents.
With this discovery, researchers believe there may be more hidden craters waiting to be found, further unraveling the mysteries of Earth’s earliest history.
