Astronomers in France, Germany, and the United States traced Theia’s origin using ancient Earth and Moon rocks.
Theia vanished billions of years ago, leaving no direct chemical evidence behind.
Scientists propose that this long-lost planet formed much closer to the Sun than previously assumed.
Theia struck early Earth about 4.5 billion years ago, scattering debris that formed the Moon.
The giant impact theory, proposed after Apollo sample analysis, has guided lunar science for over 50 years.
Researchers now aim to reconstruct Theia’s history and better understand early Solar System dynamics.
Jake Foster from the Royal Observatory Greenwich called the study remarkable for pinpointing Theia’s birthplace.
He noted that tracing a planet destroyed 4.5 billion years ago demonstrates extraordinary scientific precision.
Planetary Reverse Engineering
The team analysed isotopes of iron, chromium, zirconium, and molybdenum in Earth and lunar rocks.
These isotopes act as chemical fingerprints, revealing the original formation environments.
Earth and Moon rocks share nearly identical metal isotope ratios, complicating separation of Theia’s material.
Researchers modelled hundreds of scenarios to identify combinations matching modern isotopic signatures.
They used differences in isotopic patterns caused by formation temperatures across the Solar System.
These comparisons revealed Theia likely originated closer to the Sun than early Earth.
Previous hypotheses suggested Theia might have formed farther from the Sun, but new evidence challenges that view.
This method allows scientists to reconstruct vanished planetary bodies’ compositions and origins.
Implications for Planetary Science
Researchers hope this approach will illuminate early planetary collisions and growth processes.
The findings may refine models of how planets form, interact, and evolve in young solar systems.
Studying Theia helps explain how Earth and Moon share material while tracing the Solar System’s architecture.
Scientists anticipate applying isotopic reverse engineering to other ancient planetary fragments.
Understanding Theia’s origin may improve predictions about planetary formation in exoplanetary systems.
The study highlights how chemical fingerprints preserve records of events billions of years old.
Astronomers expect this research to guide future explorations of planetary collisions and evolution.
