近日，美国芝加哥大学Timo Hopp团队报道了形成月球的撞击物忒伊亚起源于太阳系内部。该项研究成果发表在2025年11月20日出版的《科学》杂志上。

月球是由一个名为忒伊亚的行星体与原始地球的巨大撞击形成的。目前尚不清楚忒伊亚是在太阳系内部还是外部形成的。

研究组测量了月球样品、陆地岩石和陨石中的铁同位素，这代表了忒伊亚和原始地球可能形成的同位素库。地球和月球的铁同位素组成与质量无关，难以区分；两者都定义了陨石测量范围的一端。将该结果与其他元素的结果结合起来，研究组对忒伊亚和原始地球进行了质量平衡计算。结果发现忒伊亚的全部和地球上的大部分其他组成物质都来自太阳系内部。该计算表明，忒伊亚的形成可能比地球更靠近太阳。

附：英文原文

Title: The Moon-forming impactor Theia originated from the inner Solar System

Author: Timo Hopp, Nicolas Dauphas, Maud Boyet, Seth A. Jacobson, Thorsten Kleine

Issue&Volume: 2025-11-20

Abstract: The Moon formed from a giant impact of a planetary body, called Theia, with proto-Earth. It is unknown whether Theia formed in the inner or outer Solar System. We measured iron isotopes in lunar samples, terrestrial rocks, and meteorites representing the isotopic reservoirs from which Theia and proto-Earth might have formed. Earth and the Moon have indistinguishable mass-independent iron isotopic compositions; both define one end of the range measured in meteorites. Combining our results with those for other elements, we performed mass balance calculations for Theia and proto-Earth. We found that all of Theia and most of Earth’s other constituent materials originated from the inner Solar System. Our calculations suggest that Theia might have formed closer to the Sun than Earth did.

DOI: ado0623

Source: https://www.science.org/doi/10.1126/science.ado0623