This indicates that the process that formed the Moon involved objects that were created in this neighborhood of the Solar System, making the GIH even less feasible. The results also suggest that both the Earth and the Moon had a significant component of water early in their early histories, possibly from the beginning of accretion, thus sharing the same water source.The nature of water in the lunar interior is thus not compatible with the GIH.

These results have strongly opposed the GIH as an explanation of the Moon’s formation, leaving us with more knowledge, yet farther away from a conclusion.

The takeaway

While various other modifications to the GIH have been proposed to incorporate both the evidence and counter-evidence, the fact remains that the Moon’s origin is still very much a mystery. The Apollo missions were largely in similar geological areas and yet it completely turned our understanding of the Moon’s origins on its head.

To solve the puzzle of the Moon’s origin, which is so intricately tied with that of the Earth itself, we need more data. We need access to rocks that lie deeper under the lunar surface, that haven’t been affected by meteorite impacts, cosmic rays and the solar wind. We also need to understand the origin of water in lunar poles, figure out the waters’ geological ages and understand its thermal and chemical evolution.

In other words, what we need are more missions to the surface of the Moon.

Private sector capabilities are emerging for soft-landing lunar technology. The next steps for such entities is to evolve their technologies to allow landings at sites which pertain to larger scientific questions. Can we obtain samples from Shackleton Crater? Can we go to sites untouched by geological processes? What a profound success it would be to identify the origin of the Moon. For now, it remains a mystery. Things are seldom black or white in cutting-edge science. It’s all grey, much like the Moon itself.