Scientists long lacked direct chemical evidence to trace Theia, the Moon’s precursor planet.
Astronomers in France, Germany, and the United States analysed ancient lunar and terrestrial rocks.
They discovered that Theia likely formed much closer to the Sun than previously thought.
Researchers propose that Theia struck early Earth about 4.5 billion years ago.
The collision scattered debris that eventually coalesced into the Moon.
Fragments from Theia mixed with Earth’s material, creating shared isotopic signatures.
The giant impact theory has guided Moon formation research since the first Apollo samples.
Theia’s disappearance billions of years ago prevented scientists from studying its original composition.
Jake Foster from the Royal Observatory Greenwich highlights that researchers now almost precisely pinpoint Theia’s origin.
He notes that scientists can trace a planet that vanished 4.5 billion years ago.
Planetary Reverse Engineering
Researchers examined Apollo samples and Earth rocks to study isotopes as chemical fingerprints.
They focused on iron, chromium, zirconium, and molybdenum isotopes to distinguish Earth from Theia material.
Earth and Moon rocks share nearly identical metal isotope ratios, complicating the analysis.
The team modelled hundreds of early-Earth and Theia scenarios to match observed isotopic signatures.
Materials formed closer to the Sun show different isotopic patterns than those formed farther away.
By comparing these patterns, scientists concluded that Theia came from the inner Solar System.
Previous theories suggested Theia may have formed farther out than Earth.
This method lets researchers reconstruct the properties of a planet that no longer exists.
The study demonstrates how isotopes reveal planetary origins and ancient Solar System dynamics.
Implications for Planetary Science
Scientists hope these findings improve understanding of planetary growth, collisions, and evolution.
The research could guide future models of early Solar System formation.
Astronomers plan to apply similar methods to study other vanished planetary bodies.
Understanding Theia’s origin helps explain the Moon’s composition and its relationship with Earth.
The work shows how chemical analysis of ancient rocks uncovers hidden histories of lost worlds.
Researchers emphasize that tracing vanished planets can illuminate processes shaping planets billions of years ago.
The study encourages more detailed analyses of isotopic patterns across Solar System materials.
Scientists aim to expand this research to clarify planetary formation stages and collision events.
