Astronomers traced Theia, the vanished planet that helped form the Moon, using lunar and Earth rock samples.
New research suggests Theia formed closer to the Sun than scientists previously believed.
The giant impact theory proposes Theia struck early Earth around 4.5 billion years ago.
Debris from that collision coalesced into the Moon, mixing material from both Theia and Earth.
Scientists have debated this theory since the first Apollo lunar samples more than 50 years ago.
Theia disappeared completely, leaving no direct chemical evidence to confirm its properties or origin.
Researchers in France, Germany, and the United States analysed ancient rocks to identify Theia’s birthplace.
Jake Foster of the Royal Observatory Greenwich highlighted the study’s ability to pinpoint Theia’s origin despite its disappearance.
He emphasized that scientists can reconstruct a planet that no longer exists with remarkable precision.
Planetary Reverse Engineering
The team examined Apollo lunar samples and terrestrial rocks to measure isotopic ratios.
These isotopes act as chemical fingerprints revealing each object’s formation environment.
Earth and Moon rocks share nearly identical metal isotope ratios, complicating separation of Theia’s material.
Researchers tested isotopes of iron, chromium, zirconium, and molybdenum to model hundreds of impact scenarios.
They simulated early-Earth and Theia interactions to reproduce the isotope signatures observed today.
Materials forming closer to the Sun experience different temperatures, leaving distinct isotopic patterns.
By comparing these patterns across the Solar System, scientists concluded Theia originated nearer the Sun than Earth.
This finding challenges prior beliefs that Theia formed farther from the Sun.
Insights into Planet Formation
Scientists hope this analysis advances understanding of early planetary growth and collisions.
The study provides clues on how planets interact and evolve during a solar system’s infancy.
Researchers aim to use similar techniques to study other ancient or vanished celestial bodies.
This work demonstrates that isotopic analysis can reconstruct the origins of lost worlds.
By tracing Theia’s history, astronomers gain insight into the Moon’s formation and Earth’s early development.
Future research could further clarify how collisions shaped planetary systems in the early Solar System.
The study reinforces the importance of chemical fingerprints in unraveling cosmic history.
Astronomers believe these findings will guide models of planetary evolution and formation for decades.
