This movement is called the Earth’s circulation around the Sun. This movement takes place along a path called an orbit. The orbit has the shape of an ellipse. The period of the Earth’s rotation around the Sun is 365 days 6 hours and 9 minutes. The Earth revolves around the Sun in a counterclockwise direction. On January 2, the Earth is closest to the Sun at a point called perihelion at a distance of about 147 million km. At aphelion, which occurs on July 3, the Earth’s distance from the Sun is the greatest at about 152 million km. During the year, the Earth travels a distance of about 930 million km.
The average speed of the Earth’s orbital motion is 30 km/s. The observed effect of orbital motion is the Sun’s apparent movement along a circle on the celestial sphere called the ecliptic. The Earth’s axis is inclined to the ecliptic at an angle of 66°33′, so the plane of the equator is inclined to the plane of the Earth’s orbit at an angle of 23°27′. As a direct result of this inclination, the Earth’s illumination changes throughout the year. As it moves, its surface is illuminated in different ways.
The annual rhythm of changes in latitude, in which the Sun tops at the zenith, causes an annual rhythm of changes in the Sun’s altitude and, consequently, the occurrence of astronomical seasons, which are also accompanied by a change in the duration of day and night, and thus a change in the time of sunrise and sunset. Also counted among the consequences of the circadian motion is the phenomenon of the occurrence of polar day and night.
The statement of the fact that the Earth revolves around the Sun came relatively late.
In Antiquity and the Middle Ages it was assumed that the Sun circles the Earth. It was not until 1543 that Nicolaus Copernicus changed this view, thus achieving a significant simplification regarding the structure of the entire planetary system. The current evidence in favor of the Earth’s circular motion was not known to Copernicus. One such evidence is the annual parallax of stars.
This is the phenomenon of an apparent change in the position of an object on the celestial sphere relative to further objects, resulting from a change in the place of observation due to the movement of the observer associated with the annual motion of the Earth in orbit. This apparent motion is due to the annual change in the Earth’s position in orbit. More specifically, the annual parallax is the angle at which the radius of the Earth’s orbit passing perpendicularly from the star to the Earth can be seen from a given star. A given star staggers an apparent ellipse around its mean position in such a way that it deviates toward the ecliptic from the point where the Sun is at any given time.
Displacements of this type were sought by astronomers after the promulgation of Copernicus’ theory, without supposing that, as a result of the enormous distances from the stars, parallactic motion is very small. It was not until 1838 that the first parallax was measured. The Earth’s motion around the Sun also causes a phenomenon called aberration (deflection). As we know, the Earth moves around the Sun at an average speed of 30 km/s Starlight reaches the Earth at a speed of 300,000 km/s. In order to see a given star through a telescope in the center of the field of view, it is necessary to position the telescope so that the star’s beam passes successively through the center of the telescope’s lens and reaches the center of the eyepiece…. However, when positioning the telescope in the direction of the star, the ray will not reach the eyepiece, because in the time it takes for the light to travel the length of the telescope, the Earth, together with the telescope, will move by a certain distance.
Thus, it is necessary to tilt the telescope towards the movement of the Earth by such an angle that the lens overtakes the eyepiece of the telescope. Then the observer will see a star in the center of the field of view. The angle of the telescope should be constantly directed towards the movement of the Earth. Thus, stars make an apparent motion around their mean position. As a result of aberration, a star on the celestial sphere is deflected to the direction in which the Sun was visible for ¼ of a year.
Comparing this movement of stars with the movement caused by parallax, it can be concluded that due to aberration, stars deviate from their mean position in a direction perpendicular to the parallax deviation. The phenomenon of aberration was discovered earlier than the annual parallax of stars, in 1725. Evidence of the existence of circular motion can also be found in the changes in observations of meteorites. These are small celestial bodies moving through space.
They become visible only upon entering the Earth’s atmosphere, where, due to their rapid motion, they heat up, causing them to glow, and in most cases do not reach the Earth’s surface. If it is assumed that these bodies are distributed evenly in space, the most meteorites should be seen by an observer located on the part of the globe that faces the direction of circulation. Statistical studies show that in the morning w, before sunrise, the most meteorites are observed.
