The rotation of the Earth around the Sun is a defining process on which the existence of life on the planet depends. Weather conditions, stability of the atmosphere, biosphere and other important conditions for the life of organisms depend on which side the planet is turned and what place it occupies in the solar system.
The rotation of the Earth around the Sun is a defining process on which the existence of life on the planet depends. Weather conditions, stability of the atmosphere, biosphere and other important conditions for the life of organisms depend on which side the planet is turned and what place it occupies in the solar system.
Precisely because the Earth revolves around the Sun and at the same time around its own axis, absolutely in all parts of this planet there is a periodic change of day and night, as well as a successive change of the four seasons.
The origin of the Earth’s rotation
The most common theory explains this by the processes that took place at the time of the formation of the planets. Clouds of cosmic dust “bunched up”, forming the embryos of planets, other more or less large cosmic bodies were attracted to them. Collisions with these bodies could give rotation to future planets. And then the planets continued to rotate by inertia.
Why doesn’t the Earth fall on the Sun?
As the Earth revolves around the Sun, a centrifugal force is generated that tries to continually throw our planet back. But she will not succeed. And this is because the Earth always moves around the star at the same speed and is at a safe distance from it, correlated with the centrifugal force, with which they are trying to knock the Earth out of orbit. That is why the Earth does not fall on the Sun and does not fly into space, but continues to move along a given trajectory.
Rotation of the Earth around its axis
The planet revolves around itself from west to east. We do not feel this process because all objects move simultaneously and parallel to each other together with the cosmic body. During the rotation of the Earth around its axis, only two points remain stationary: the North and South Poles. If you connect them with an imaginary line, you get an axis around which the Earth rotates.
The earth’s axis is not perpendicular, but is at an angle of 23.5 ° to the earth’s orbit.
One such revolution of the Earth is called a day and lasts 24 hours, more precisely – 23 hours 56 minutes and several seconds. The planet moves from west to east. This phenomenon explains the change of day and night: the day is observed on the half of the globe that is illuminated by the Sun, and the night is on the shadow side.
A day is divided into 24 hours (1440 minutes, or 86,400 seconds) and is conventionally divided into four characteristic intervals – morning, afternoon, evening and night.
Calendar days are weeks, months.
The rotation of the planet has the following features and consequences:
- When viewed from the North Pole, the planet rotates counterclockwise.
- The angle of rotation is 15 degrees per hour and is the same at any point on the Earth.
The linear speed of revolutions throughout the planet is not uniform. At the poles, it is equal to zero and increases as it approaches the equator. It looks like this. The city of Quito is located near the equatorial line, which means that he and its inhabitants, imperceptibly for themselves, make a turn with the Earth at a speed of 465 m / s.
True and mean solar time
Local true solar time is determined by the position of the Sun. Due to the fact that the orbit in which the Earth moves around the Sun is not a circle, and the Earth’s axis is tilted (which is why the seasons on the Earth change), the true solar time is uneven. The maximum difference in the duration of true solar days during the year is about 50 s, and the deviation of the start of the day from its average value can reach 16 minutes.
The exact local true solar time can be found by measuring the hour angle of the Sun with a special astronomical instrument. The approximate solar time can be found by the sundial.
Sundial
Local true solar time was used in the life of an ordinary person until about the 18th century. By the end of the 18th century, mechanical watches became widespread, the design of which was more and more improved. Various states gradually began to use the mean solar time, preferring it to the true one. So in Geneva it was introduced from 1780, in London – from 1792, in Berlin – from 1810, in Paris – from 1816.
