The 5 movements of Earth
The 5 movements of Earth
When we were kids, we were taught in school how, despite the fact that in ancient times the Earth was believed to be flat and the center of the universe, thanks to great figures in history, it was shown that the earth was neither flat nor the center of the universe. In fact, this is the one that revolves around the sun, performing the movement known as translation, and while it revolves around the sun it also revolves around itself, performing the movement of rotation.But beyond all this, they did not tell us anything else, even though there is. The Earth does not only move around the sun and on itself, but also has three additional main movements: precession of the equinoxes, nutation and Chandler wobble.In addition to these five main movements, there are other movements historically considered secondary such as the variations of the elliptical plane in which the translation movement is described, the variations in the eccentricity of the ellipse described in this movement, or the movements that the Earth makes for being inside the Solar System, or for being inside the Milky Way.
Rotatory motion
This movement, well known to all, is defined as that which makes the Earth on its own axis. The rotation is the movement by which there are days and nights, and each rotation has a duration of practically a day (more specifically are 23 hours 56 minutes and 4.1 seconds).
It can not be said that there is a single discoverer of the existence of this movement, although the first to make a firm proposal was Johannes Müller in the 15th century, although it was not until later, with the help of Copernicus and Newton, when the existence of the terrestrial rotation was fully demonstrated.
Movement of Translation
Like the movement of rotation, the translation is well known to all. It is defined as the movement made by the Earth around the sun, describing an ellipse that takes 365 days, 5 hours and 47 minutes to travel. Due to the fact of traveling an orbit, the Earth varies its distance from the sun while describing this trajectory, giving perihelion (point closest to the sun) the first days of January, and aphelion (point farthest from the sun) the first days of July.
The first to firmly propose the existence of this movement was the Greek Philolaus of Crotona, although the followers of the geocentric theory kept this thought buried until in the 16th century Copernicus revolutionized astronomy with its heliocentric model that, despite not being the first Yes, he was the first to receive great support and respect for the society of the time.
Precession Movement of the EquinoxesAlthough at the beginning of the article I have affirmed that in the schools only translation and rotation movements are taught, it is true that some fortunate ones have been able to be enlightened in a third earth movement not as well known as the two previous ones. The precession movement of the equinoxes is the one that describes the inclined axis of the earth in a circular way. More concretely, it is the movement that makes the north terrestrial pole with respect to the central point of the ellipse that describes the Earth in the movement of translation.This movement was described and calculated for the first time in ancient Greece by Hipparchus of Nicaea. The fundamental physical cause of the existence of this movement is the moment of force exerted by the Sun on Earth, although this movement is also strongly affected by the movement of tectonic plates, so its periodicity is not as precise as in the case of rotation and translation movements. Even so, its estimated duration is 25,780 years, which is also known as the Platonic year.
Nutation Movement
Entering already in more complex movements, we find the movement of nutation. The axis of the Earth, as we have just described in the previous point, moves in a circular way by means of the precession movement, but the circles that it describes are not exact. In fact, the movement of nutation what it does is to generate oscillations causing the axis of the earth to incline a little more or a little less with respect to the circumference that describes the movement of precession.
This movement was discovered in 1728 by James Bradly, but when he announced it he did not yet know the cause of its existence. This was demonstrated 20 years later, when the calculations of different physicists and astronomers determined that this movement was caused directly by the gravitational attraction of the Moon.
Rotatory motion
This movement, well known to all, is defined as that which makes the Earth on its own axis. The rotation is the movement by which there are days and nights, and each rotation has a duration of practically a day (more specifically are 23 hours 56 minutes and 4.1 seconds).
It can not be said that there is a single discoverer of the existence of this movement, although the first to make a firm proposal was Johannes Müller in the 15th century, although it was not until later, with the help of Copernicus and Newton, when the existence of the terrestrial rotation was fully demonstrated.
Movement of Translation
Like the movement of rotation, the translation is well known to all. It is defined as the movement made by the Earth around the sun, describing an ellipse that takes 365 days, 5 hours and 47 minutes to travel. Due to the fact of traveling an orbit, the Earth varies its distance from the sun while describing this trajectory, giving perihelion (point closest to the sun) the first days of January, and aphelion (point farthest from the sun) the first days of July.
The first to firmly propose the existence of this movement was the Greek Philolaus of Crotona, although the followers of the geocentric theory kept this thought buried until in the 16th century Copernicus revolutionized astronomy with its heliocentric model that, despite not being the first Yes, he was the first to receive great support and respect for the society of the time.
Precession Movement of the EquinoxesAlthough at the beginning of the article I have affirmed that in the schools only translation and rotation movements are taught, it is true that some fortunate ones have been able to be enlightened in a third earth movement not as well known as the two previous ones. The precession movement of the equinoxes is the one that describes the inclined axis of the earth in a circular way. More concretely, it is the movement that makes the north terrestrial pole with respect to the central point of the ellipse that describes the Earth in the movement of translation.This movement was described and calculated for the first time in ancient Greece by Hipparchus of Nicaea. The fundamental physical cause of the existence of this movement is the moment of force exerted by the Sun on Earth, although this movement is also strongly affected by the movement of tectonic plates, so its periodicity is not as precise as in the case of rotation and translation movements. Even so, its estimated duration is 25,780 years, which is also known as the Platonic year.
Nutation Movement
Entering already in more complex movements, we find the movement of nutation. The axis of the Earth, as we have just described in the previous point, moves in a circular way by means of the precession movement, but the circles that it describes are not exact. In fact, the movement of nutation what it does is to generate oscillations causing the axis of the earth to incline a little more or a little less with respect to the circumference that describes the movement of precession.
This movement was discovered in 1728 by James Bradly, but when he announced it he did not yet know the cause of its existence. This was demonstrated 20 years later, when the calculations of different physicists and astronomers determined that this movement was caused directly by the gravitational attraction of the Moon.
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