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New Study Reveals Theia's Origins in Inner Solar System

11/23/2025

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Summary

Story summary

Earth and Moon have nearly indistinguishable iron isotopic compositions, complicating conclusions about Theia's exact nature.
Researchers at the Max Planck Institute and the University of Chicago analyzed iron isotopes in 15 terrestrial and six lunar samples.
They suggest Theia originated closer to the Sun in the inner Solar System.
The findings, published in Science, illuminate early Earth–Moon formation.

History

Historical Context

The giant-impact hypothesis, proposed in 1946, suggests that the Moon formed from debris after a Mars-sized body, Theia, collided with Earth about 4.5 billion years ago. Recent studies from the Max Planck Institute and the University of Chicago support this theory, indicating that Theia likely originated from the inner Solar System, sharing isotopic similarities with Earth, which is vital for understanding planetary formation.

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Story summary

Earth and Moon have nearly indistinguishable iron isotopic compositions, complicating conclusions about Theia's exact nature.
Researchers at the Max Planck Institute and the University of Chicago analyzed iron isotopes in 15 terrestrial and six lunar samples.
They suggest Theia originated closer to the Sun in the inner Solar System.
The findings, published in Science, illuminate early Earth–Moon formation.

1 / 2