The mystery of the Moon’s two faces could soon be solved
Long ago, something odd must have happened way back when the Moon first formed. We aren’t sure exactly what it was or how it happened, but the aftermath of those events led to a tremendous set of differences between the Moon’s near side — the side that always faces us — and the far side, which can only be accessed via spacecraft. The near side is full of familiar and recognizable features, including:
But the far side, which was only glimpsed for the first time with a 1959 space mission, is very different. It’s almost exclusively comprised of heavily cratered highlands, and the few dark, low-lying maria that are present are very small in comparison to the near side. The simplest explanation for this effect is already known to be wrong, but a wild-yet-compelling theory is about to be put to the test. Now that China’s Chang’e-6 mission has successfully returned lunar samples taken from the Moon’s far side to Earth for the first time in human history, we can at last analyze them and compare them to near side samples that have been around since the Apollo era. After all these years, the mystery of the Moon’s two hemispheres could finally be solved.
The differences between the lunar near side and the lunar far side are striking, as most of us would struggle to even recognize our own Moon if all we saw were the side that always faces away from Earth. Instead of a large number of dark, lightly cratered maria, there’s only one substantial one: located on the far side’s northern hemisphere. There are no giant mountain ridges, like the one prominently separating Mare Imbrium from Mare Serenitatis on the near side. There are fewer giant craters with enormous rays radiating out from them, like Giordano Bruno and Pierazzo, whereas the near side is rife with them: Copernicus, Aristarchus, Kepler, Tycho, and many more.
