<\/p>\n But the new analysis of moon samples from Apollo missions, terrestrial rocks and meteorites now argues that Theia, much like Earth, was a rocky world that formed in the inner solar system<\/a> \u2014 likely even closer to the sun than our planet.<\/p>\n You may like<\/p>\n “Theia and proto-Earth come from a similar region of the inner solar system,” Timo Hopp<\/a>, a geoscientist at the Max Planck Institute for Solar System Research in Germany, who led the research, told Live Science.<\/p>\n The findings, detailed in a paper published Nov. 20 in the journal Science<\/a>, reinforce the classical picture of how rocky planets assembled billions of years ago, Hopp said.<\/p>\n “Our results do not predict a new twist in the mechanism,” Hopp said. Instead, they “are in very good agreement from what we expect from the classical theory of terrestrial planet formation.”<\/p>\n Violent youth of the planets<\/p>\n In the turbulent first 100 million years after the sun formed, the inner solar system<\/a> was crowded with dozens to hundreds of planetary embryos \u2014 moon- to Mars-size worlds that frequently collided, merged or were kicked into new orbits by the gravitational chaos of early planet formation, as well as by Jupiter’s immense pull.<\/p>\n “Theia was one of 10-100s of planetary embryos from which our planets formed,” said Hopp. But lunar samples from the Apollo missions have shown that Earth and moon are nearly chemically identical, a similarity that scientists say has made pinpointing Theia’s birthplace extremely difficult.<\/p>\n To investigate, Hopp and his colleagues searched for minuscule chemical clues left behind from the impact in Earth’s mantle \u2014 traces of elements such as iron and molybdenum that should have sunk into Earth’s core if they had been present early in the planet’s formation. Their survival in mantle rocks today suggests these elements arrived later, likely delivered by Theia during the giant impact, and therefore carry valuable information about the lost planet’s composition, the researchers say.<\/p>\n \n Lunar rocks collected during the Apollo 17 mission, like this one, helped the researchers probe the history of Earth, the moon, and Theia. (Image credit: NASA)Clues from the moon<\/p>\n The researchers analyzed six lunar samples from the Apollo 12 and 17 missions alongside 15 terrestrial rocks that included specimens from Hawaii’s K\u012blauea volcano, as well as meteorites recovered from Antarctica and curated in major museum collections.<\/p>\n You may like<\/p>\n![\"Lunar](\"https:\/\/www.newsbeep.com\/au\/wp-content\/uploads\/2025\/12\/bushCjAepLc7jDGKjkE8nA.jpg\")
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