Sometimes called the dark side of the Moon, scientists have long been peering at this intriguing face of the Moon that isn’t exposed to us. However, its common nickname is misleading because the “dark” side of the Moon is not actually dark. It is simply unseen and seldomly explored by us. It is not always facing away from the Sun and drowned in darkness. In fact, the Moon has its own days and night just like the Earth, and therefore both the far and the near side receive an equal amount of sunlight.
But even since we’ve been observing the Moon, we’ve always only been looking at one side because it is tidally locked to the Earth, meaning that it rotates on its own axis with the same period that it orbits the Earth, leaving one side of the Moon always facing away from us. Nonetheless, not the whole far side of the Moon is all that mysterious to us for due to a phenomenon called “wobble” or vibrations (when the Moon slightly shifts on its axis), depending on the phase of the Moon, it may reveal up to 18% of its far side to us, human observers on the surface of the Earth.
How the far side differs from the Moon we know?
There is a difference between what we find on the near and the far side of the Moon. Typically, on the far side of the Moon, you would encounter a much rougher surface with more pronounced or deeper craters and much less Maria, which are the large and dark patches that you can see on the Moon’s surface and are speculated to be remainders of what were vast magma oceans which followed violent eruptions.
The reason for the difference in asperities and appearance between both sides was thought to be due to the Earth acting as a shield for meteor showers, allowing less of them to reach the nearside of the Moon. However, this theory has now been disproved. Instead, the explanation behind the different-looking faces is the consistency of the crust being colder and thicker on the far side. Therefore, the thinner crust on the near side has allowed many more magma eruptions to occur, causing the lava to fill some of the larger craters and smoothen the surface to create the aforementioned darker Maria.
The observations of the Moon’s far side
The Soviet Space Probe Luna 3, the third probe of the USSR to be sent to the Moon, was first to photograph the far side of the Moon in 1959, bringing back to Earth photographs of its imposing craters. Soviet scientists then used these images to produce the first-ever map of the Moon’s far side. In 1968, humans had the chance to experience the far side of the Moon when Apollo 8 orbited the Moon before returning to Earth. What makes the far side of the Moon so intriguing is the difficulty of reaching it with radio communications, for the Moon blocks radio waves. For example, the astronauts of the Apollo 8 mission lost all contact with mission control during their passage behind the Moon.
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Landings on the far side of the Moon
Up until 2019, we had seen and thoroughly studied the far side of the Moon but had never landed on it. All previous missions to the Moon had landed on the near side to avoid communication issues. However, the Chinese Space Administration found a way around this problem by launching a relay satellite Queqiao which orbited the Earth.
On the 3rd January 2019, the Chang’e 4 Probe of the Chinese Space Administration landed its Yutu 2 lunar rover on the far side of the Moon, more specifically in the Von Kármán crater, to study the soil composition and temperatures, unexpectedly discovering that it’s actually much colder than expected, a phenomenon which they attempted to explain through soil composition.
Thanks to the abilities of the Chinese satellite Queqiao we now have technically solved the communications and can peer into the numerous interesting insights that the far side of the Moon might hold for the future of space exploration. Of course, it could serve as a settlement base.
Still, one of its more interesting applications is to use it as a launch base for missions going beyond the Moon as the Moon’s escape velocity is considerably lower than that of the Earth because its mass to radius ratio is smaller. More realistically, the far side of the Moon is a prime location for eventual radio telescopes to avoid any interference from Earth. In other words, although the far side of the Moon remains quite similar to the face we all know, its orientation holds many opportunities for expanding our capacities in space exploration.
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