It was believed that the moon is the product of a collision between the Earth and another planet. The scientists started to question that theory.
It had been believed that the Mars-sized infant planet – known as Theia, which is “the mother of the moon” in Greek mythology – hit Earth with a glancing blow, striking at a 45 degree angle some 4.5 billion years ago.
This suggests, according to their study published in Science, that the impact between Earth and Theia was so powerful that parts of Theia and the Earth merged to boost our planet and create a lunar satellite.
Edward Young, lead author and a University of California 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.”
Mr Young explains that had it just been a glancing blow, the majority of the moon would be made up of Theia and would have different oxygen isotopes.
But because they are so similar, it suggests that it is virtually made up of the same composition.