According to a new study, the moon was created after an impact between Earth and Theia 4, 533 billion years ago. The previous theory dictated that our planet’s natural satellite was formed after the two celestial bodies scraped each other. New evidence shows it was not just a scrape, but actually a very powerful impact.
A new study in the Science journal has revealed a link between the rocks that have been brought back from the moon’s surface and normal Earth rock samples. It seems that the two types of rocks indicate the existence of a large deflagration that led to the formation of the natural satellite that orbits our planet.
For the study, the team of researchers used rock samples that were brought back by the three moon expeditions, Apollo 12, 15 and 17 as well as pieces of a meteorite that they believe originated from the moon.
The analysis of the two samples indicated that both had the same levels of oxygen isotopes. This translates to the fact that two celestial bodies have the same origins, and that the moon was most probably formed after a violent impact that detached a portion of the Earth surface.
Cosmochemistry and geochemistry professor at UCLA and lead author of the cited study, Edward Young, says that the oxygen isotopes in the two samples of rocks are indistinguishable. This means that Theia was dispersed equally between the two bodies.
Theia is a planet which existence is hypothesized by astronomers and researchers. According to the theory, the ancient planet was roughly the size of today’s version of Mars. The distance between Theia and Earth was rather small which led, 4,533 million years ago to an impact between the two.
The debris that formed after the impact of the two planets originally formed two smaller artificial satellites. These two forms then collided again to form the moon that we see today in the night sky.
The impact also merged the two planets together, this being a plausible explanation for the increased density of the Earth’s core and for the resemblance of oxygen isotopes from our planet and the natural satellite that orbits around it.
Young explains that the impact is reconstructed using the oxygen atoms’ chemical signature. A rock is made up out of oxygen in a 90 percent proportion. The most common oxygen isotopes found on Earth is O-16 with eight neutrons and eight protons, but there is also O-17, which is heavier due to the extra neutron, and O-18, that is even heavier because it has two neutrons extra.
The ratio in which these isotopes are found in our solar system differs from planet to planet. The rocks collected from the moon have the exact same ratio as the Earth has. This is what led scientists to believe that the moon was created after an impact between earth and Theia.