25 November 2023

The rotational motion of the Earth is the movement of our planet rotating on its own axis. This is responsible for the daily cycle of day and night, it has important consequences on the shape, climate and geography of the world.

## Concept and definition of rotational movement

It is the daily rotation of the Earth on its imaginary axis. The planet makes its re-entry in a west-east direction and completes its complete translation on its axis in 24 hours, which is known as an Earth day.

This movement is responsible for the succession of day and night in different parts of the world. The Earth is divided into 24 time zones, each with an hour difference from the next, the rotation of the planet is the function that determines the beginning and end of the day in each place on the globe.

The formula in fact that calculates the length of the day is the following: t = 24 hours * (1 + 0.00274 cos(2θ)). where t is the length of the apparent solar day in hours, θ is the angle of the Sun’s position relative to a reference point on Earth. This varies throughout the year due to the tilt of the Earth’s axis and its orbit around the Sun.

The cosine function in the equation represents the variation of the position of the Sun in relation to the mean position, which is what makes the length of days varies throughout the year.

Rotational speed varies depending on the geographical location and the seasons of the year, due to the irregular shape of the planet and the influence of external factors, such as the Moon and the Sun.

To describe the movement of rotation, we use a vector called the axis of rotation. This vector points from the center of the Earth toward a point in space called the north celestial pole. The translational displacement of the Earth occurs around this axis of rotation.

In addition to being responsible for the day and night cycle, the rotation of the Earth also has other important effects. Like the generation of centrifugal force that produces a bulge at the equator. Likewise, the deviation of moving bodies to the right in the northern hemisphere and to the left in the south, known as the Coriolis effect.

In general, the displacement of the Earth’s rotation is a fundamental phenomenon in life on our planet and the study of physics and geography.

## What is the Earth’s rotation movement for?

It is of vital importance for life on our planet. as it has various implications and impacts that are essential for existence in the world.

One of the most important effects of rotational motion It is the cycle of day and night. The Earth’s spin causes the Sun to appear over the horizon, moving up in the sky during the day and then disappearing at the end of the day, giving way to night. This regular phase of light and dark is essential in the circadian cycle of living beings, including humans, who have evolved to adapt to this pattern of sleep and wakefulness.

Another important effect of rotation is the creation of centrifugal force, which causes the planet to have a bulge at the equator. This bulge is responsible for the flattened shape of our world and affects the distribution of Earth’s weight and mass, which in turn has implications for gravity and geodesy.

Furthermore, the displacement it also has an important reaction on climate and meteorology. The path of the gyre creates the Coriolis effect, which causes winds and ocean currents to bend to the right in the northern hemisphere and to the left in the south. This effect is responsible for the creation of wind patterns and high and low pressure systems that affect global climate.

## What causes the rotational movement?

This is caused by a combination of the conservation of angular momentum and the gravitational force. Angular momentum is a physical property that describes the amount of rotational movement of an element, it is conserved when there are no external forces acting on the object. Since the Earth is not in contact with any other external force, its angular momentum is conserved and its rotation continues.

On the other hand, the gravitational force, exerted by the volume of the Earth, acts on its own mass and generates angular momentum toward the east. This gravitational force also affects the rotation of other bodies in the solar system, such as the Moon and other planets.

Together, these two forces interact to Keep the world scrolling steadily. However, there are other factors that can affect the rate of spin, such as the influence of the Moon and the Sun, the distribution of mass in the interior of the planet, and the geological and atmospheric processes that occur on its surface.

In addition, mathematics has to do with the movement of the Earth’s rotation, since it is based on the use of trigonometry. In particular, the cosine function is used to calculate the position of the sun in the sky during the day and at night. The position of the sun in the sky is determined by the angle it makes with the horizon, this angle can be calculated using the cosine.

Therefore, we can conclude that, heRotation is caused by conservation of angular momentum and the gravitational force exerted by its own mass, is essential for life on our planet and thus understand physics and geography.

## How long does the rotation of the Earth last?

The time it takes for the globe to make a complete revolution on its own axis is 24 hours, which is known as an Earth day.

This period of rotation has been measured with great precision using astronomical techniques, it has been determined that it varies according to several factors, such as the influence of the Moon and the Sun, the terrestrial tides and the distribution of the mass inside the planet.

For example, in the 1960s, it was discovered that the rotation of the world was gradually slowing down, which led to the addition of a leap second to atomic clocks to keep time coordinated with the rotational motion of the Earth.

Although the Earth day has an average span of 24 hours, does not mean that the duration of the day and night are the same in all parts of the world. This is due to the tilt of the planet’s spin axis. This causes the north and south poles to be permanently dark for part of the year and continuously illuminated for another part. While on the other hand, the equatorial regions experience almost equal continuous days and nights throughout the year.

Therefore, the rotation movement of the Earth lasts 24 hours, but its Actual duration may change due to various factors.

## What are the consequences of rotational motion?

The rotational movement of the Earth has several major consequences on our planet, some of which are as follows:

• Day-night cycle: Due to rotation, there is a daily period of light and dark, which is essential for life on the planet and for the regulation of the biological rhythms of living beings.
• Coriolis: Rotation also generates an effect known as Coriolis, which cause the deviation of the movements of objects that move on the Earth’s surface, including winds and ocean currents.
• Shape and dimensions of the Earth: The rotation It also influences your figure. since it makes the equatorial thickness greater than the polar diameter.
• Climate changes: The rotation of the Earth also influences the environment, such as the formation of the trade winds and ocean currents, as well as in the distribution of solar radiation on the earth’s surface.
• Gravitational attraction: Finally, the rotation of the Earth also influences gravity, which is the force that keeps objects on the earth’s surface. gravitational power it looks affected by the shape and mass of the planet, which in turn are influenced by their turns.

Therefore, we can define that the displacement of the turns of the Earth has several important consequences. ranging from the day-night cycle to weather patterns and the shape and dimensions of the Earth. These are fundamental to understanding the geography and physics of our planet.