Did Earth Create the Moon? Research Uncovers Clues About Lunar Formation

A recent investigation into the moon’s formation and Earth’s water origin has provided compelling insights. Researchers from the University of Göttingen and the Max Planck Institute for Solar System Research (MPS) conducted analyses on lunar and terrestrial samples, revealing that the moon was likely formed predominantly from Earth’s mantle material. This challenges the long-held theory that the protoplanet Theia contributed significantly to the moon’s composition. The findings also shed light on Earth’s early water acquisition, suggesting a re-evaluation of existing assumptions.

New Findings on Moon’s Formation

According to the study published in Proceedings of the National Academy of Sciences, oxygen isotopes from 14 lunar samples and 191 terrestrial measurements were examined using laser fluorination. The study observed a close isotopic resemblance between oxygen-17 isotopes from both the moon and Earth. This finding contradicts prior theories attributing the moon’s composition to a major contribution from Theia, the protoplanet believed to have collided with Earth billions of years ago.

Professor Andreas Pack, Managing Director of the Geoscience Centre at the University of Göttingen, explained to phys.org that Theia’s earlier collisions might have stripped it of its mantle. The collision with Earth could have occurred as a “metallic cannonball,” leading to the moon’s formation from ejected mantle material.

Implications for Earth’s Water History

The data has also prompted new discussions about the origin of Earth’s water. As per reports, the widely accepted Late Veneer Event theory—suggesting water arrived after the moon’s formation through subsequent impacts—is being questioned. First author Meike Fischer, formerly at MPS, stated in reports that the isotopic consistency between Earth and the moon rules out many meteorite types as the source of water. Enstatite chondrites, a class of meteorites with isotopic similarity to Earth and sufficient water content, are suggested as the likely contributors to Earth’s water.

These findings provide critical insights into the intertwined histories of Earth’s development and the moon’s formation, advancing understanding of planetary evolution.