- Moon
- Origin and formation of the Moon
- Characteristics of the Moon
- Moon phases
- Relief of the Moon
- Movements of the Moon
- The tides
We explain everything about the Moon, its formation, movements, relief and other characteristics. Also, its impact on the tides.
Moon
The moon is the only one natural satellite that revolves around the Earth at a distance of approximately 385 thousand kilometers. It is the fifth largest satellite in the Solar system.
It takes 28 Earth days to go around the planet (movement of translation) and to rotate on its own axis (rotational movement) so that the same lunar face is always seen from the Earth.
In 1609, the Italian Galileo Galilei (astronomer, philosopher, engineer, mathematician and physicist) built the first telescope of sixty magnifications, with which he discovered the moutains and the craters of the Moon. Furthermore, he observed that the Milky Way was composed of stars and detected the four major satellites of Jupiter.
On July 20, 1969, American astronaut Neil Alden Armstrong was the first man to set foot on the Moon. So far, twelve humans have set foot on the lunar surface after various expeditions. In November 2009, the discovery of Water on the Moon, after an operation carried out by NASA.
Origin and formation of the Moon
There are various scientific theories that explain the possible origin of the Moon. The most recent theory is called the "big impact theory" and it postulates its formation four and a half million years ago, as the result of a great collision between the Earth and Mars (when protoplanets were in their formation phase).
From the fragments that were detached from the crash, a celestial body was formed in which its magma melted until it crystallized and gave rise to the lunar crust. The star kept his orbit around the Earth and became its natural satellite.
Other theories formulated in previous years are:
- Of binary creation. It maintains that the Moon and the Earth originated in parallel, and that the satellite was the consequence of small particles that merged over thousands of years.
- From the catch. He maintains that the Moon was originally a planet independent that, due to the Earth's orbit and gravitational force, remained as its satellite trapped in Earth's orbit.
- From fission. He maintains that the Moon was separated from the Earth while the latter was in the process of formation and gradually solidified until it became the natural satellite. This theory was discarded due to the differences that both celestial bodies present in their composition.
Characteristics of the Moon
The surface of the Moon has deep craters and high mountain systems.The Moon is a rocky celestial body. Its diameter is 3,474 kilometers (a quarter of the diameter of planet Earth) and it is characterized by having a surface with deep craters and high mountain systems. It is composed, for the most part, of oxygen, silicon, calcium, magnesium and aluminum.
Its atmosphere (called the “exosphere”) is weak and light, so it cannot contain gases such as oxygen, nor can it maintain the temperature, which drastically oscillates between 110º and -170º Celsius.
The Moon does not shine with its own light, but reflects the light that you receive from Sun and that is why it can be seen from the Earth and can be appreciated in its different instances or "phases".
These phases are produced by the variations in the position of the Moon with respect to the luminous star and the Earth, which generate more or less shadow on the satellite. The complete cycle that includes all the phases of the Moon is 29 days, 12 hours and 44 minutes, also called the "lunar month".
Moon phases
The phases of the Moon are the changes of the illuminated part, which allow us to appreciate it in its entirety or in part. The same face is always visible due to the synchronization that exists between what it takes to go around the Earth and to rotate on its own axis (both processes are carried out in 28 days).
The phases of the Moon are four and last about a week each:
- New Moon. It occurs when the Moon is closer to the Sun, its illuminated part is not visible from the Earth and therefore it is almost imperceptible from the planet.
- Crescent quarter. It occurs when half of the Moon is illuminated: the right side is illuminated from the northern hemisphere and the left side is illuminated from the southern hemisphere. It occurs after the new moon and it is possible to observe it in the afternoon and in the first half of the night.
- Full moon. It occurs when the satellite is more distant from the Sun and one of its faces is fully illuminated, so the Moon is seen complete from Earth, throughout the night.
- Last quarter. It occurs when half of the Moon is illuminated, but in a decreasing way (unlike the waxing Moon) and, the visible half varies according to the terrestrial hemisphere from which it is observed. It is possible to see it at dawn and in the morning.
Relief of the Moon
The surface of the moon was studied through various expeditions (both manned and unmanned) carried out during the years 1969 and 1972.
From the samples obtained, it was found that it presents a solid and rocky soil with a multitude of rubble, craters and basins. Among other reasons, accidents in your relief They are because it does not have a atmosphere consistent to protect it against the impact of asteroids or other smaller celestial bodies.
It has mountains up to 9,140 meters high and some volcanoes that have been inactive for millions of years. It is estimated that, in addition to the mountain ranges, the areas of plain or plateaus correspond to old seas, the largest detected is 1,120 kilometers in diameter.
There are also valleys deep so-called "lunar fissures" that reach 480 kilometers long and 3 kilometers wide. It is estimated that they were formed as a consequence of heat and expansion originated inside the satellite.
Movements of the Moon
The moon performs two primary movements:
- The translation. It is the movement of the satellite around the Earth, which takes 28 days, that is, about a month. In addition, it performs the translational movement around the Sun.
- Rotation. It is the rotation of the satellite on its own axis and in an easterly direction that it also performs in 28 days.
The orbit of the Moon is inclined at a different angle to that of the Earth and the Sun, so that only at two points of its trajectory can they occur eclipses of the Sun and Luna, respectively.
When the satellite is exactly aligned between the Sun and the Earth, it produces a lunar eclipse (It happens when the planet is interposed between the luminous star and the Moon).
The tides
The gravitational force of the Moon influences the tides on Earth. When both stars are at a close distance, part of the mass of terrestrial water that is facing the Moon, is attracted by it and the flow of terrestrial water increases.
The Sun also influences the tides due to its Gravitational force, but with less intensity due to its distance from Earth.
The tides do not always vary at the same time, but depend on the phases of the moon and its alignment with the Sun. They can be:
- Spring tides. They are those high tides that are generated with the new Moon, in which the satellite and the Sun align, merging both gravitational forces.
- Neap tides. They are those small tides that are generated during the phases of the waxing and waning Moon.