New insights have emerged on the formation of the Moon. It now seems that it was created almost entirely from materials ejected from the Earth.
Previously the formation was focussed on a collision between the Earth and the protoplanet Theia.
A study by the University of Göttingen and the Max Planck Institute for Solar System Research (MPS) also found that water probably reached the Earth early in its development, rather than through later impacts.
“The prevailing theory was that the Moon was the result of a collision between the early Earth and the protoplanet Theia,” the study report said.
“New measurements indicate that the Moon formed from material ejected from the Earth’s mantle with little contribution from Theia.”
The researchers analysed oxygen isotopes from 14 samples from the Moon and did 191 measurements on minerals from Earth.
These new measurements showed a very high similarity between the isotope samples taken from both Earth and the Moon.
“One explanation is that Theia lost its rocky mantle in earlier collisions and then slammed into the early Earth like a metallic cannonball,” Professor Andreas Pack, Managing Director of Göttingen University’s Geoscience Centre and Head of the Geochemistry and Isotope Geology Division said.
“If this were the case, Theia would be part of the Earth’s core today, and the Moon would have formed from ejected material from the Earth’s mantle. This would explain the similarity in the composition of the Earth and the Moon.”
The full report is on the University of Göttingen website.
