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Asteroids shaped Earth’s atmosphere

Asteroids shaped Earth’s atmosphere

Researchers from the Southwest Research Institute and other academic centers have developed a comprehensive new scheme on the impacts of asteroids on Earth in the Archaic aeon, 2.5 to 4 billion years ago: it serves to understand how asteroids may have affected the oxygen levels in the Earth’s atmosphere.

According to a Press release, scientists concluded in a new study, published recently in the journal Nature Geoscience, that the Earth was subjected to a substantial number of large asteroid impacts throughout the late Archaic era. Specialists believe that the flow of impacts has been underestimated: it would have been up to 10 times greater than indicated for that period in current theories.

Initial bombings

Scientists came to this conclusion after adding the latest geological evidence from ancient and starring collisions. asteroids large. Through this data, they discovered that “Impact spherules”, which are “signals” in the form of glassy particles that are buried in the earth as evidence of the impact of a huge asteroid, were in a much greater quantity than expected.

These particles generated multiple thin layers in the Earth’s crust, with ages ranging between 2.4 and 3.5 billion years. Spherule layers are ancient collision markers: in recent years a number of new layers have been identified in drill cores and rock outcrops, consequently increasing the total number of known impact events during the Primitive earth.

According to experts, the early bombing could have delayed oxidation of the earth’s atmosphere: it is worth remembering that the abundance of oxygen in the atmosphere of our planet is due to the balance of the production and elimination processes. Everything indicates that the impacts of bodies of more than 10 kilometers in diameter may have contributed to their scarcity in the initial period, since the limited oxygen present in the atmosphere of the early Earth would have been chemically consumed by the vapors generated in the impacts.

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Related topic: Planetary defense against dangerous asteroids goes on the offensive.

The great oxidation

Meanwhile, the planet also endured a substantial number of major impacts throughout the late Archaic era. During the end of this “bombardment”, about 2.4 billion years ago, the Earth underwent a major change in its surface chemistry, generated by the increase in atmospheric oxygen. This phenomenon has been called Great Oxidation Event (GOE), attributed to multiple changes in oxygen production.

While the impact vapors caused low oxygen levels in certain periods before the GOE, over time the collisions of asteroids became less and less frequent and too irrelevant to be able to significantly alter the oxygen levels. It was at that moment that the Earth achieved the necessary balance and began the journey to become the planet we know today.


Delayed and variable late Archaean atmospheric oxidation due to high collision rates on Earth. Marchi, S., Drabon, N., Schulz, T. et al. Nature Geoscience (2021) .DOI:

Cover photo: The researchers updated the asteroid “planetary bombardment” models with the latest geological information, applying them to understand how the impacts may have affected oxygen levels in Earth’s atmosphere during the planet’s formation period. Credit: SwRI / Dan Durda, Simone Marchi.

Video and podcast: edited by Pablo Javier Piacente based on elements and sources free of copyright. Video Image Credits: SwRI / Dan Durda, Simone Marchi, UCLA / Scott Hassler, Oberlin / Bruce Simonson, Bryan Goff, Chris Henry, Fábio Lucas and Andy Holmes on Unsplash.

Music video and podcast: Lesfm and Pixabay.

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