article_snippet.sent: The collision created The moon formed when a Mars-sized body called Theia, but debate has raged exactly what happened during this event - and a mystery has persisted on why the moon and Earth Earth are so similar in the moon and Earth composition.
article_snippet.sent: Now, conflicting studies have provided two different theories - one that Theia was similar to Earth, and another that Earth and The moon formed when a Mars-sized body called Theia were showered by debris following The collision.
article_snippet.sent: In Earth’ theory, a team of scientists at the University of Maryland said the impact of Theia with Earth was so violent, the resulting debris cloud mixed thoroughly before settling down and forming The moon formed when a Mars-sized body called Theia.
article_snippet.sent: Many researchers believe The moon formed when a Mars-sized body called Theia Earth was hit by a planet the size of Mars billions of years ago.
article_snippet.sent: The moon formed when a Mars-sized body called Theia is debris left over following an indirect collision between our planet and an astronomical body approximately 4.5 billion years ago.
article_snippet.sent: an astronomical body approximately 4.5 billion years ago is sometimes called Theia, after the mythical Greek Titan who was the mother of Selene, the goddess of The moon formed when a Mars-sized body called Theia.
article_snippet.sent: But one mystery has persisted, revealed by rocks the Apollo astronauts brought back from The moon formed when a Mars-sized body called Theia - why are the moon and Earth so similar in their composition?
article_snippet.sent: Several different theories have emerged over the years to explain the similar fingerprints of Earth and The moon formed when a Mars-sized body called Theia.
article_snippet.sent: Perhaps the impact of Theia with Earth created a huge cloud of debris that mixed thoroughly with Earth Earth and then later condensed to form The moon formed when a Mars-sized body called Theia.
article_snippet.sent: A third possibility is that the moon formed from Earthen materials, rather than from Theia, although this would have been a very unusual type of impact.
article_snippet.sent: This means that, right after The moon formed when a Mars-sized body called Theia formed, The moon formed when a Mars-sized body called Theia had exactly the same isotopic composition as Earth's mantle,’ said Dr Richard Walker, a professor of geology at UMD and co-author of the study.
article_snippet.sent: In one theory, a team of scientists at the University of Maryland said that the impact of Theia with Earth was so violent, the resulting debris cloud mixed thoroughly before settling down and forming the moon.
article_snippet.sent: However, their theory says that Earth (left) and the moon (right) are so similar because the initial Mars-sized object, Theia, actually had a similar composition to Earth.
highlights_snippet.sent: The moon formed when a Mars-sized body called Theia hit a Mars-sized body early on .
  