Scientists long searched for clues about Theia, the vanished planet that helped form the Moon.
Theia disappeared billions of years ago, leaving no direct chemical traces for researchers.
Astronomers in France, Germany and the United States studied ancient Earth and lunar rocks to track Theia’s birthplace.
They found evidence suggesting Theia formed much nearer to the Sun than earlier theories proposed.
Researchers concluded that Theia likely emerged from the inner Solar System before striking early Earth.
For decades, scientists supported the giant impact theory, which states Theia collided with Earth.
That massive collision scattered debris that created the Moon and left Theia’s material in both bodies.
Early Apollo samples strengthened this theory, though Theia’s unknown makeup left many questions.
Scientists struggled for years to determine where Theia originated and how it formed.
New rock analysis now offers insight into those long-standing mysteries.
Jake Foster from the Royal Observatory Greenwich praised the findings for pinpointing Theia’s origin.
He noted that Theia vanished 4.5 billion years ago, yet researchers can still trace its birthplace.
Chemical Clues from Two Worlds
Scientists used terrestrial rocks and Apollo lunar samples to investigate isotope fingerprints.
These isotopes act as chemical markers that reveal the environments where materials formed.
Earth and Moon rocks share nearly identical metal isotope ratios, complicating earlier research.
That similarity made it difficult to distinguish early Earth material from Theia’s remnants.
The new study relied on a form of planetary reconstruction to separate these signatures.
Researchers examined isotopes of iron, chromium, zirconium and molybdenum in both sets of rocks.
They modelled hundreds of early Solar System scenarios to match today’s isotope patterns.
Regions nearer the Sun formed under hotter and different conditions than outer locations.
These varied conditions produced distinct isotope patterns across the Solar System.
By comparing those patterns, scientists identified Theia’s likely origin in the inner Solar System.
Earlier theories suggested Theia might have formed farther out, contradicting the new evidence.
Rewriting Early Solar System History
The new analysis indicates Theia formed even closer to the Sun than early Earth.
This discovery reshapes scientists’ understanding of early planetary formation and movement.
Researchers believe this approach can guide future studies of planetary growth and collisions.
Understanding Theia’s path may reveal how young solar systems evolve through impacts.
Scientists hope these findings inspire new models of how planets shift and interact over time.
The results highlight the value of combining lunar samples with Earth’s oldest rocks.
Such comparisons offer rare glimpses into events that shaped Earth and Moon formation.
The study shows how precise isotopic analysis can uncover the origins of long-lost worlds.
Researchers now view Theia’s history as a key chapter in the Solar System’s earliest era.
