A new isotopic study reveals that Theia—the Mars-sized body that struck Earth 4.5 billion years ago to form the Moon—likely originated in the inner Solar System, close to Earth’s birthplace. By comparing heavy-element isotope ratios in lunar rocks, Earth samples, and meteorites, researchers found identical signatures, showing both worlds formed from the same inn…A new isotopic study reveals that Theia—the Mars-sized body that struck Earth 4.5 billion years ago to form the Moon—likely originated in the inner Solar System, close to Earth’s birthplace. By comparing heavy-element isotope ratios in lunar rocks, Earth samples, and meteorites, researchers found identical signatures, showing both worlds formed from the same inn…
