More than other space objects from ancient times, the moon attracted man. The reverse side of it, hidden from the earth observer, generated many fantasies and legends, associated with everything mysterious and incomprehensible. The scientific study of the inaccessible part of the satellite began in 1959, when it was photographed by the Soviet station "Luna-3". Since then, the data on the back of the night luminary has been substantially replenished, however, the number of questions related to it has decreased slightly.
Synchronization
Today, almost everyone knows what is causing one of the main features that characterizes the moon. The reverse side of the satellite is hidden from the observer located on Earth, due to the synchronization of the movement of the night luminary around the axis and our planet. The time required per revolution is the same in both cases. It should be noted that the reverse side of the satellite is illuminated by the Sun in the same way as the visible one. The epithet “dark”, often used to characterize this region of the moon, is used more likely in the figurative meaning: “hidden”, “unknown”.
It is likely that after some time the Earth will also be turned to its satellite with only one of its parts. The mutual influence of two cosmic bodies can lead to complete synchronization. Examples of a system with a similar coincidence of the periods of movements are Pluto and Charon - both bodies are constantly turned to the companion on the same side.
Librations
More than half of the satellite’s surface, approximately 59%, can be observed from our planet. This is explained by the so-called librations - the visible vibrations of the satellite. Their essence is that the orbit of the moon’s revolution around the planet is somewhat elongated. As a result, the object’s speed changes and a longitude libration occurs: a part of the surface in the east, then in the west becomes visible to the earth observer.
The inclination of the satellite axis also affects the increase in the area available for “viewing”. It causes libration in latitude: from the Earth, the north or south pole of the moon becomes visible.
Secrets of the century: the reverse side of the moon
The study of the satellite using spacecraft began in 1959. Then two Soviet stations reached the night luminary. Luna-2 was the first device in history to reach the satellite (this happened on September 13, 1959). Luna-3 photographed about half the surface of the cosmic body, with two-thirds of the footage taken on the opposite side. Data has been transmitted to Earth. So began the study of the moon from the "dark", hidden side.
The first Soviet photographs were of rather low quality due to the peculiarities of technical development at that time. However, they made it possible to see some of the nuances of the surface and give individual sections of the relief of the name. The Soviet name of the objects was recognized throughout the world and fixed on the maps of the moon.
Modern stage
Today the map of the far side of the moon is fully compiled. Some of the latest data about it were obtained by American astronomers in 2012. They noticed geological neoplasms on a surface hidden from the Earth’s observer, indicating a longer geological activity of the satellite than previously thought.
Today, new space explorations of the moon are planned. According to many astronomers, the satellite of our planet is a great place to place extraterrestrial bases in the future. Therefore, an accurate understanding of the surface features of the object is necessary. The study helps, in particular, to answer the question of where it is better to land a spaceship: on the back of the moon or on its visible part.
Features
After a more detailed study of the part of the satellite hidden from observation, it became clear that its surface is in many ways different from the visible half. Huge dark spots that invariably adorn the face of the night luminary are a constant attribute that distinguishes the Moon visible from Earth. The reverse side, however, has practically no such objects (in astronomy they are called seas). There are only two seas - the Sea of Moscow and the Sea of Dreams, with a diameter of 275 and 218 kilometers, respectively. The most characteristic objects for the reverse side are craters. They are found on the entire surface of the satellite, but it is here that their concentration is greatest. Moreover, many of the largest craters are also located on the back side.
Giants
Among the most impressive objects on the reverse side of the satellite of our planet, a huge hollow stands out. The basin with a depth of approximately 12 and a width of 2,250 kilometers is the largest such formation in the entire solar system. The size of the craters of Hertzsprung and Korolev is also amazing. The diameter of the first is nearly 600 km, and the depth is 4 km. Korolev on its territory has fourteen smaller craters. Their sizes vary from 12 to 68 km in diameter. The radius of the Korolev crater is 211.5 km.
The moon (the reverse side and the visible part), according to scientists, is a source of minerals that can be very useful to humanity in the future. Satellite research is therefore necessary. The moon is a real candidate for the location of extraterrestrial bases, scientific and industrial. In addition, due to its relative proximity, the satellite is a suitable object for practicing manned flight skills and testing technologies and engineering systems designed specifically for space exploration.