Moon: History of discoveries
After the Sun, the Moon is certainly the star who most needed his presence in the skies of Earth Our satellite also has something "more": the complexity of its cycles .This gave him a special significance both in mythologies that in the oldest astronomy.
As was the case for all the stars, from the seventeenth century, the use of raw glasses, and the advent of Newtonian mechanics, a new way of viewing the moon is made daily. The complexity of its movement only became more evident, and its study has now found new tools provided by celestial mechanics. But above all, its surface has now been studied in detail. The first maps of the moon were drawn and she was born selenography, which runs from mid-nineteenth century through photography.
Along the way, astronomers have watched on the surface of our satellite variations, real or imagined. This questions is found intimately linked with that of the possibility of this geologic activity on the Moon. In particular, the question arose whether the craters and lunar seas were volcanic or whether to invoke other causes. If astronomers have finally opted for the meteorite hypothesis
picture
It took them to wait for the exploration of the Moon from 1960 to be able to base this conclusion on a solid argument.
Key dates
640 BC. AD: Thales recognizes the lunar phases a result of the reflection of sunlight.
1609: First observations of the Moon by Galileo using a telescope.
1830-1837: Publication by Beer and Maedler their map of the Moon.
1833 To calculate the inequalities of the Moon, Fish provides a process that is incomplete for a theory of our satellite, but which could be applied with advantage in the case of the planets.
1787 Herschel believes observe a volcanic eruption on our satellite (Aristarchus crater).
1840: First photographs of the Moon.
1894 -1910: Photographic Atlas Publication of the Moon Loewy and Puiseux.
1959: First shot from the opposite side of the Moon by the probe Luna 3.
1969-1972: Twelve human trample on the moon in the Apollo program.
The phases of the Moon.
(According Hevelius)
The moon before telescope
Moon played a big role in all mythologies. Its cycles, often put in relation with the idea of fertility, were all closely monitored. From the seventh century BC, the Ionian philosophers also began to speculate on the nature of this star. Is this a fiery or earthy body? A perfect crystal sphere or another habitable earth? These issues will be discussed, in different variations, until the appearance of the first telescopes in the seventeenth century.
Steps selenography
As its etymology suggests, selenography is to the moon, what geography is to the Earth. The principles are the same, but measurements, remained for a long indirect, made this term synonymous primarily lunar mapping. The observation in 1609 by Galileo and his contemporaries of the Moon's surface with the first glasses revealed the presence of mountains associated with clear our satellite regions. But the question that immediately arose was whether the dark regions, in contrast, were not seas. We quickly abandoned this idea. The current nomenclature of the Moon, the first steps back to the cards Hevelius and Riccioli, however, still bears traces of these questions. Following these seminal works, it should be noted cartographic efforts Cassini, Tobias Mayer, Schroeter, to Lohrmann and Schmidt, and especially Beer and Maedler whose card, completed in 1837, represents the last great completion of selenography before the use of the photograph.
At the age of photography
The first photographs of the Moon date back to 1840. Although this new technique is not able to compete with the direct observation with regard to the fine detail that can be detected, it brings a certain objectivity, allowing its use for achieving new maps of our satellite. Photographic Atlas of the Moon, directed by Loewy and Puiseux between 1894 and 1910 is probably the culmination of this approach. But photography has other early recognized benefits. And Will it be used for photometric studies, or to explore the beaches of the electromagnetic spectrum located beyond the visible range. Today, traditional photography is hardly used by astronomers. However, it has known a last moment of glory during the exploration of our satellite program in the 1960s, during which we could take pictures of the Moon "on site".
The variations on the Moon?
Observers such as William Herschel, Schroeter Gruithuisen, Littrow, believed distinguish our satellite traces of constructions "made by human hands." Kepler himself in the Dream says that lunar craters are too regularly trained for nature is responsible. A closer look obviously every time then proved that these constructions (walls, trenches, canals and roads supposedly) were not artificial but purely natural formation. However, these detailed observations, if misinterpreted, also brought to light the possibility of changes to the surface of the Moon, also called transient lunar phenomena (LTP). Episodic lights, craters that change shape. This showed it to the existence of current geological activity on our satellite? Could they claim the existence of a volcanic earthquakes or the pest on the Moon? Nobody believes today. But astronomers of the past had their reasons to think otherwise.
The origin of the craters and seas
The generations of astronomers who have followed in an attempt to detect changes on the surface of the Moon often had in mind the possibility that the Moon is the seat of volcanic eruptions. Indeed, such a type of geologic activity has long been privileged to explain these formations called craters. It showed craters of volcanoes, extinct in the main, but some of which could still give some signs of activity. It was the volcanic hypothesis of the origin of lunar craters and seas. But another option began to be seen around 1895 and eventually prevailed from the 1960s is the meteorite hypothesis. Thus, astronomers now recognize that the craters of the moon have nothing volcanic, but instead were formed during a large meteorite bombardment that took place in the early days of the Solar System
Space exploration
Long destination imaginary journeys, the moon has begun to be considered seriously as a goal reached by few engineers of the early decades of the twentieth century engaged in the development of the first rocket engines (Robert Goddard, Robert Esnault-Pelterie, etc.) . But it was not until after the Second World War, to the availability of technologies developed for military purposes (mainly the German V1 and V2 rockets), added to the context of the Cold War place in 1953 to priority programs access to space. Reach the moon being then very quickly perceived as a sign of technological expertise required to launch intercontinental missiles, and the most obvious symbol of the victory of one or the other side in this new conflict so strongly tinted propaganda.
The first firing of rockets towards the moon date from 1958, and the following year, the first automatic probes effectively managed until our satellite. Quickly, these test shots called the emergence of human spaceflight programs, an American on the Soviet side. It is essentially to prepare for the arrival of the first man on the moon that will be scheduled the launch frenzy that constantly occur over the following decade. launch. Finally, three years after the first soft landing of a Soviet probe, the first American crew of the Apollo program in 1969 set foot on the Sea of Tranquility
Since then, one is tempted to say that the whole thing summed up in one sentence: we walked on the moon and came back. A total of sixty trips to the moon will take place. Nearly 400 kilograms of moon rocks will have been reported to Earth to be studied there. Only eight trips (all belonging to the Apollo program) have been inhabited, six moon landings, which have allowed twelve humans to set foot on our satellite. Yet even as the Cold War that justified all this no longer appears as a spasm of our history, the first lunar exploration program have fundamentally changed the vision we can have today world. They marked a turning point not only in the history of knowledge, but in human history.
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