The interior of the moon may hide from us the planet Theia, or what was left of it after the collision with the Ground. This assumption was made by scientists from the University of new Mexico — UNM (USA), discovering Earth and its satellite different mixtures of oxygen isotopes. Article about it was published in the journal Nature Geoscience.
The hypothesis of the so-called giant impact, which suggests that the Moon formed from debris after a collision between early Earth and protoplanets named Theia, for a long time. Their geochemical similarity (the conclusion was made on the basis of the analysis brought from the moon regolith) has long been the main argument of “shock” version, which read that Theia crashed into the Earth at a tangent, causing the formation of large splinter from which later formed the Moon.
However, the former results, confirming the similarity of oxygen isotopes on Earth and moon have not been confirmed. A group of specialists from the Department of Earth Sciences and planets UNM held additional high-precision measurements of isotopic composition of oxygen in some lunar samples in the Center of UNM. Samples included basalts and highland anorthosites, norite and volcanic glass, product recrystallizing quickly cooling magma.
Scientists have discovered that the isotopic composition of oxygen varies depending on the type of the studied rocks. The isotopes of oxygen from samples of the deep lunar mantle, the most different from the oxygen isotopes from Earth.
“These data suggest that the deep lunar mantle may have experienced the least mixing with the earth rocks and therefore is the most viable candidate for the substance of which was Theia,” said study leader Zach Sharpe.
Review leading specialist GEOKHI im. Vernadsky RAS Alexander Bazilevsky:
– A magazine which published this news, it is considered very prestigious, and unreliable results he post n I would. It is clear that measurements of isotopic composition of oxygen, carried out by scientists from the University of new Mexico, fine. The question that can and should discuss how these measurements are interpreted. As they notice the difference in the compositions of the different rock types, see something of a trend, and say that they are the traces of that body, which once crashed into the Ground. But we can say that while they noted the difference a reasonable explanation can not be. Measurements little. Maybe what seems to be a trend – it was an accident. And indeed the hypothesis of the formation of the moon due to impact on Earth of a body the size of Mars – it is a hypothesis. It was based just on similarity of isotopic composition of oxygen and Earth’s moon. But if they are different, it is possible, for example, to think that the Moon was formed somewhere and just captured the Earth in its present orbit.