Researchers have found more evidence suggesting the moon was created in an ancient collision with the Earth and a planet-sized object.
The researchers measured oxygen isotopes to make their findings, a European Association of Geochemistry news release reported.
The ancient planet that is believed to have collided with the Earth was dubbed Theia.
In order to prove that this ancient impact happened researchers measure the ratios between isotopes such as oxygen, titanium, and silicon, the news release reported.
Ratios are different in different parts of the solar system, but those on Earth and the moon are extremely similar. This disputes the idea that the moon was mostly made from Theia.
Researchers compared the ratios of 17O/16O in lunar samples with similar samples from Earth. The research was first conducted on bits of lunar material that hitched a ride to Earth on meteorites, but these may have been contaminated by Earth.
The team looked at fresher samples from the NASA's Apollo 11, 12 and 16 missions. These samples had significantly higher levels of 17O/16O than those from Earth.
"The differences are small and difficult to detect, but they are there. This means two things; firstly we can now be reasonably sure that the Giant collision took place. Secondly, it gives us an idea of the geochemistry of Theia. Theia seems to have been similar to what we call E-type chondrites**.If this is true, we can now predict the geochemical and isotopic composition of the Moon, because the present Moon is a mixture of Theia and the early Earth. The next goal is to find out how much material of Theia is in the Moon".
The researchers believe the moon is made up of between 70 and 90 percent of material from Theia, with the other material coming from Earth.
