www.sciencedaily.com
A massive collision between Earth and the Mars-sized Theia about 4.5 billion years ago dramatically shaped our planet and birthed the Moon. Scientists are piecing together Theia’s identity and origin by analyzing isotopic signatures present in Earth and lunar rocks. These subtle chemical differences provide clues about Theia’s composition and where it formed in the early solar system, revealing details of this cataclysmic event that fundamentally altered the history of Earth and its celestial companion.
