Study Suggests Earth’s Moon Formed From a Close Neighbor   

• Roughly 4.5 billion years ago, when Earth was still young and partly molten, it was struck by a planet roughly the size of Mars. The massive collision blasted debris into space, and over time, that material came together to form the moon. Called the “Giant Impact Hypothesis,” this idea is the leading explanation for the moon’s origin. For years, one major question remained unanswered: Where did the crashing planet come from? The hypothetical planet, named Theia, was long believed to have formed far from Earth in another part of the solar system. But new research suggests otherwise. Scientists at Germany’s Max Planck Institute for Solar System Research analyzed tiny chemical markers called isotopes in rocks from the Earth, the moon, and nearby meteorites. Acting as chemical fingerprints, isotopes reveal the physical and chemical environment in which the object was formed. The researchers found that Earth and the moon share nearly identical isotope patterns, while the meteorites do not. The findings suggest Theia formed from the same material as Earth and developed nearby, making it a close neighbor rather than a distant visitor. This discovery helps scientists better understand how planets formed, though questions remain about how the materials mixed so completely during the collision. J.K. Park Staff Reporter junior/1768462299/1613367801