Earth's early chemistry stabilises fast as Theia impact brings water
Updated
Updated · The Brighter Side of News · May 1
Earth's early chemistry stabilises fast as Theia impact brings water
8 articles · Updated · The Brighter Side of News · May 1
University of Bern researchers say proto-Earth's chemistry locked in within about three million years of Solar System formation, likely leaving an initially dry, volatile-poor planet.
Using manganese-chromium isotope analysis and modelling, the study argues the later Moon-forming collision with Mars-sized Theia supplied water and other volatile elements needed for habitability.
Published in Science Advances, the work suggests habitable rocky worlds may depend on rare late impacts, while major uncertainties remain over Theia's composition and how volatiles survived the collision.
If a giant impact delivered our water, what was the chemical makeup of Theia, the planet that hit us?
Earth was born dry, but other planets form wet. Which evolutionary path is more likely to create a habitable world?
If Earth's habitability was a cosmic accident, how many worlds are one lucky impact away from life?
Theia's Inner Solar System Origin and Its Role in Delivering Earth's Water: Insights from 2025–2026 Isotopic Studies
Overview
Recent studies reveal that Theia, the Mars-sized body that collided with early Earth forming the Moon, originated in the inner Solar System and was likely dry. This means Theia was not the main source of Earth's water. Instead, Earth's core chemical composition stabilized rapidly within three million years after the Solar System formed, leaving the planet dry and depleted in volatiles. Water and other essential elements arrived later, delivered by smaller, volatile-rich bodies from the outer Solar System. The giant impact caused thorough mixing of Earth and Moon materials, but Earth's habitability depended on this late volatile delivery, making its life-supporting conditions a rare and fortunate outcome in planetary evolution.