14 DAY TRIAL // Most people know that the far side of the Moon is hidden from us at all times, mostly due to the fact that the celestial body spins around its axis at about the same time it spins around our planet. For a very long time, astronomers wondered what the other side looked like, and these questions started getting answers with the beginning of the Space Age and the launching of the first lunar probe, which sent back for the first time pictures of the far side of the Moon. It was then that researchers found huge discrepancies between the geological aspects found on our natural satellite's two “faces.”
The near-side, as everyone with a telescope can see, is covered with smooth and dark pools of solidified lava, which give it the grayish aspect we see when a full Moon is out. Until getting their hands on the first images of the other side, researchers believed that it too looked in very much the same way, an idea that was dismissed thoroughly upon inspecting the snapshots. The far, or “dark,” side of the Moon is almost entirely covered in a heavily cratered bright material, which bears the mark of countless encounters with various asteroids and meteorites that would have otherwise made their way to Earth.
The Japanese SELENE lunar mission is currently relaying numerous data regularly, in a bid to understand exactly what has created these differences, and how is it that the two sides have grown so apart from each other over the 4 billion years that passed since the satellite was created. The main theory behind the forming of the Moon, in a nutshell, is that it's the result of a collision between a Mars-sized object and Earth that occurred before our planet was solidified. A large chunk of magma was ejected into space, where it took on orbit around our planet, and began to crystalize.
As a result, our satellite was completely covered in magma when first created, which further amplified the mystery of the differences between the two sides. According to readings sent back by SELENE, it were the internal factors that caused the separate evolution, although up until this point they themselves have remained a mystery. However, this brings astronomers a bit closer to identifying what has brought about the differences, and hopefully, in time, they will be able to figure out exactly what happened.