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Study Reveals Theia's Origins Closer to the Sun

12/2/2025

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Summary

Story summary

The study in Science concludes Theia originated in the inner Solar System, possibly closer to the Sun than Earth.
Researchers analyzed Apollo lunar samples and terrestrial rocks, focusing on iron isotopes to trace Theia's composition.
Theia is described as a rocky world with a metal core, about 5–10% of Earth's mass.
Despite Earth–Moon chemical similarities, how their identities merged remains unclear.

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Story summary

The study in Science concludes Theia originated in the inner Solar System, possibly closer to the Sun than Earth.
Researchers analyzed Apollo lunar samples and terrestrial rocks, focusing on iron isotopes to trace Theia's composition.
Theia is described as a rocky world with a metal core, about 5–10% of Earth's mass.
Despite Earth–Moon chemical similarities, how their identities merged remains unclear.