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At what speed does the Earth turn in orbit. At what speed does the Earth move around the Sun

Very many of the habits of life that we are familiar with since childhood are the result of processes of cosmic scale. The change of day and night, the seasons, the length of the period during which the Sun is above the horizon, are related to how and how fast the Earth rotates, with the peculiarities of its movement in space.

The Imaginary Line

The axis of any planet is a speculative design created for the convenience of describing the movement. If we mentally draw a line through the poles, this will be the axis of the earth. The rotation around it is one of the two main movements of the planet.

The axis does not make with the plane of the ecliptic (the plane of rotation of the Earth around the sun) 90º, but deviates from the perpendicular by 23º27 '. It is believed that the planet rotates from west to east, that is, counterclockwise. This is what it looks like about the axis, if you watch it at the North Pole.

Compelling evidence

Once it was believed that our planet is still, and the stars fixed in the sky revolve around it. For quite a long time in history nobody was interested in the speed with which the Earth turns in orbit or around the axis, because the very concepts "axis" and "orbit" did not fit into the scientific knowledge of that period. The experimental proof of the fact of the constant motion of the Earth around the axis was obtained in 1851 by Jean Foucault. It finally convinced everyone who in the century before last had doubted this.

The experiment was conducted in the Parisian Pantheon, under the dome of which a pendulum and a circle with divisions were placed. Swinging, the pendulum with each new movement was shifted by several divisions. This is possible only if the planet rotates.

Speed

How fast does the Earth rotate around its axis? A unambiguous answer to this question is rather difficult, because the speed of different geographical points is not the same. The closer the terrain to the equator, the higher it is. In the Italian region, the speed value, for example, is estimated at 1200 km / h. On the average, the planet overcomes 15 ° per hour.

With the speed of Earth's rotation, the duration of the day is related. The time span for which our planet makes one revolution around the axis is determined in two ways. To determine the so-called stellar or sidereal days, any star other than the Sun is chosen as the reference frame. They last 23 hours 56 minutes and 4 seconds. If the starting point is taken by our luminary, then the day is called solar. Their average value is 24 hours. It varies somewhat depending on the position of the planet relative to the luminary, which also affects the speed of rotation around the axis and the speed with which the Earth orbits.

Around the center

The second most important movement of the planet is its "spinning" in orbit. The constant movement along a slightly elongated trajectory is felt by people most often by the change of seasons. The speed with which the Earth moves around the Sun is expressed primarily for us in terms of time: one revolution takes 365 days 5 hours 48 minutes 46 seconds, that is, an astronomical year. The exact figure clearly explains why every four years in February there is an extra day. It is the sum of the hours accumulated during this time, not included in the accepted 365 days of the year.

Features of the trajectory

As already noted, then, with what speed the Earth turns in orbit, is associated with the characteristics of the latter. The trajectory of the movement of the planet differs from the ideal circle, it is slightly elongated. As a result, the Earth then approaches the light, then moves away from it. When the planet and the sun share a minimum distance, this position is called perihelion. The maximum removal corresponds to the aphelion. The first falls on January 3, the second - on July 5. And for each of these points the question: "At what speed does the Earth rotate in orbit?" - has its own answer. For aphelion this is 29.27 km / s, for perihelion - 30.27 km / s.

Duration of the day

The speed with which the Earth rotates in an orbit, and in general the movement of the planet around the Sun have a number of consequences that determine many of the nuances of our life. For example, these movements affect the duration of the day. The sun constantly changes its position in the sky: the points of sunrise and sunset are shifting, a slightly different altitude of the light above the horizon at noon. As a result, the duration of the day and night changes.

These two values coincide only in the equinox, when the center of the sun crosses the celestial equator. The inclination of the axis is thus neutral with respect to the luminary, and its rays plummet to the equator. The spring equinox falls on March 20-21, the fall equinox on September 22-23.

Solstice

Once a year, the day reaches its maximum in duration, and in six months - the minimum. These dates are usually called the solstice. Summer falls on June 21-22, and winter falls on December 21-22. In the first case, our planet is so located with respect to the luminary that the northern edge of the axis looks in the direction of the Sun. As a result, the rays plummet to the northern tropic and illuminate the whole region beyond the Arctic Circle. In the southern hemisphere, on the contrary, the sun's rays reach only the region between the equator and the Arctic Circle.

During the winter solstice, the events proceed in exactly the same way, only the hemispheres change roles: the South Pole is illuminated.

Seasons

The position in the orbit affects not only how fast the Earth moves around the Sun. As a result of the change in the distance separating from the luminary, as well as the inclination of the axis of the planet throughout the year, the solar radiation is unevenly distributed. And this, in turn, is the reason for the change of seasons. And the duration of the winter and summer half-year is different: the first is 179 days, and the second - 186. This discrepancy is caused by the same inclination of the axis relative to the plane of the ecliptic.

Belt of illumination

The spinning of the Earth along the orbit has one more consequence. The annual movement leads to a change in the position of the Sun above the horizon, as a result of which the belts of illumination have formed on the planet:

  • Hot places are located on 40% of the Earth's territory, between the Southern and Northern Tropics. As you can see from the name, the most heat comes here.

  • Moderate belts - between the Arctic Circle and the Tropics - are characterized by a pronounced change of seasons.

  • Polar belts, located beyond the Arctic Circles, are characterized by low temperatures throughout the year.

The motion of the planets as a whole and, in particular, the speed with which the Earth orbits, affect other processes. Among them, the flow of rivers, the change of seasons, certain rhythms of life of plants, animals and humans. In addition, the rotation of the Earth, due to its influence on illumination and surface temperature, affects agricultural work.

Today, what is the speed of the Earth's rotation, what is its distance to the Sun, and other features related to the motion of the planet, are studied in school. However, if you think about it, they are completely unobvious. When such an idea comes to mind, I would like to thank those scientists and researchers who in many ways, thanks to their extraordinary intellect, were able to discover the laws of the cosmic life of the Earth, describe them, and then prove and explain them to the rest of the world.

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