Earth is actually a combination of two planets, i.e. Earth and Theia, a planet thought to be about the size of Mars.
Researchers from University of California Los Angeles (UCLA) have recently reported that there was a “violent, head-on collision” of Earth and Theia, which is thought to be an ancient planet having the approximate size of Mars or according to some it was about Earth’s size, about 4.5 billion years ago, when our planet was just 100 million years old. The collision resulted in the development of a single planet, i.e. our planet. The collision also became the cause of the creation of Earth’s moon, i.e., a piece of the planet broke and entered the gravitational pull to form a moon.
In the study, researchers studied moon rocks taken brought by three Apollo missions and made a comparison with volcanic rocks found in Arizona and Hawaii. They found that the rocks have no differences in the oxygen isotopes and they have similar chemical markers.
Edward Young, author of the new research and a UCLA professor of geochemistry and cosmochemistry, said, “We don’t see any difference between the Earth’s and the moon’s oxygen isotopes; they’re indistinguishable.”
“This suggests that well-mixed material from the giant impact must have formed both the Moon and Earth’s mantle,” noted the journal.
“Theia was thoroughly mixed into both the Earth and the moon, and evenly dispersed between them. This explains why we don’t see a different signature of Theia in the moon versus the Earth,” said Young.
UCLA – Moon was produced by a head-on collision between Earth and a forming planet – http://goo.gl/yEX3zZ
Young, E., Kohl, I., Warren, P., Rubie, D., Jacobson, S., & Morbidelli, A. (2016). Oxygen isotopic evidence for vigorous mixing during the Moon-forming giant impact Science, 351 (6272), 493-496 DOI: 10.1126/science.aad0525