A study presented at the geochemistry conference Goldschmidt states that Land primitive suffered city-sized asteroid bombings about 10 times more than previously thought. Space rocks, similar to the asteroid that decimated the dinosaurs 66 million years ago, fell on our planet, on average, every 15 million years between 2,5 and 3,5 billion years ago.

“We developed a new impact flow model and compared it to a statistical analysis of data from the old spherical layer. With this approach, we found that current Earth bombing models severely underestimate the number of known impacts as recorded by the spherical layers. The impact flow could have been up to a factor 10 times greater than previously thought in the period between 3,5 and 2,5 billion years ago. This means that in that early period, we were probably being hit by an impact the size of the caused in Chicxulub crater (in Mexico) on average every 15 million years. Quite a spectacle!”, detailed researcher Dr Simone Marchi, from the Southwest Research Institute, located in the city of Boulder, in the United States.


Read more:

“As we deepen our understanding of the early Earth, we discover that cosmic collisions are like an elephant in the room. They are often overlooked as we do not have a detailed knowledge of their number and magnitude, but it is likely that these energetic events have fundamentally altered the evolution of the Earth's surface and the Earth. atmosphere“, she completed.

One of the points observed by scientists is whether these collisions may have affected the evolution of atmospheric oxygen. “We found that oxygen levels would have fluctuated dramatically during the period of intense impacts. Given the importance of oxygen to Earth's development and, indeed, to the development of life, its possible connection to collisions is intriguing and deserves further investigation. This is the next stage of our work”, explained Dr Simone Marchi.

Asteroids "disturbed" the Earth

Dr. Rosalie Tostevin of the University of Cape Town, South Africa, agrees that these large asteroid impacts would certainly have caused some disturbance to Earth: “Unfortunately, few rocks that far away survive, so direct evidence of impacts and of its ecological consequences are irregular. The model proposed by Dr. Marchi helps us to better understand the number and size of collisions on the early Earth.”

The researcher also points out that some chemical markers suggest that there were oxygen “breaths” in the primitive atmosphere, before a permanent ascent about 2,5 billion years ago. “But there is considerable debate over the meaning of these 'blows', or even whether they occurred. We tend to focus on Earth's interior and the evolution of life as controls for the Earth's oxygen balance, but bombing with space rocks offers an intriguing alternative.”

Have you watched our new videos on YouTube? Subscribe to our channel!