The average distance from the Earth to the Sun is approximately 150 million kilometers. But since rotation of the earth around the sun occurs not in a circle, but in an ellipse, then at different times of the year the Earth is either a little further from the Sun, or a little closer to it.

In this real photo, taken using slow motion, we see the path the Earth takes in 20-30 minutes relative to other planets and galaxies, rotating around its axis.

Change of seasons

It is known that in summer, during the hottest time of the year - in June, the Earth is approximately 5 million kilometers further from the Sun than in winter, in the coldest time of the year - in December. Hence, change of seasons occurs not because the Earth is further or closer to the Sun, but for another reason.

The Earth, in its forward motion around the Sun, constantly maintains the same direction of its axis. And during the progressive rotation of the Earth around the Sun in orbit, this imaginary Earth’s axis is always inclined to the plane of the Earth’s orbit. The reason for the change of seasons is precisely that the Earth's axis is always inclined to the plane of the Earth's orbit in the same way.

Therefore, on June 22, when our hemisphere has the longest day of the year, the Sun illuminates the North Pole, but the South Pole remains in darkness, since the sun’s rays do not illuminate it. When summer in the Northern Hemisphere has long days and short nights, in the Southern Hemisphere, on the contrary, there are long nights and short days. Consequently, it is winter there, where the rays fall “obliquely” and have low calorific value.

Temporal differences between day and night

It is known that the change of day and night occurs as a result of the rotation of the Earth around its axis (more details:). A temporal differences between day and night depend on the rotation of the Earth around the Sun. In winter, on December 22, when the longest night and shortest day begin in the Northern Hemisphere, the North Pole is not illuminated by the Sun at all, it is “in darkness,” and the South Pole is illuminated. In winter, as you know, residents of the Northern Hemisphere have long nights and short days.

On March 21–22, day is equal to night, it comes the vernal equinox; the same equinox - already autumn– sometimes on September 23rd. These days, the Earth occupies such a position in its orbit relative to the Sun that the sun's rays simultaneously illuminate both the North and South poles, and they fall vertically on the equator (the Sun is at its zenith). Therefore, on March 21 and September 23, any point on the surface of the globe is illuminated by the Sun for 12 hours and is in darkness for 12 hours: all over the globe day is equal to night.

Climate zones of the Earth

The rotation of the Earth around the Sun also explains the existence of various Earth's climate zones. Due to the fact that the Earth has a spherical shape and its imaginary axis is inclined to the plane of the earth's orbit always at the same angle, different parts of the earth's surface are heated and illuminated by the sun's rays in different ways. They fall on certain areas of the surface of the globe at different angles of inclination, and as a result, their calorific value in different zones of the earth's surface is not the same. When the Sun is low above the horizon (for example, in the evening) and its rays fall on the earth's surface at a slight angle, they heat very weakly. On the contrary, when the Sun is high above the horizon (for example, at noon), its rays fall on the Earth at a large angle, and their calorific value increases.

Where the Sun on some days is at its zenith and its rays fall almost vertically, there is the so-called hot belt. In these places, animals have adapted to the hot climate (for example, monkeys, elephants and giraffes); Tall palm trees and bananas grow there, pineapples ripen; there, under the shadow of the tropical Sun, with their crown spread wide, there stand gigantic baobab trees, the thickness of which reaches 20 meters in girth.

Where the Sun never rises high above the horizon are two cold belts with poor flora and fauna. Here the flora and fauna are monotonous; large spaces are almost devoid of vegetation. Snow covers vast expanses. Between the hot and cold zones there are two temperate zones, which occupy the largest areas of the surface of the globe.

The rotation of the Earth around the Sun explains the existence five climate zones: one hot, two moderate and two cold.

The hot zone is located near the equator, and its conventional boundaries are the northern tropic (Tropic of Cancer) and the southern tropic (Tropic of Capricorn). The northern and southern polar circles serve as the conventional boundaries of cold belts. The polar nights last there for almost 6 months. There are days of the same length. There is no sharp boundary between thermal zones, but there is a gradual decrease in heat from the equator to the South and North Poles.

Around the North and South Poles, vast spaces are occupied by continuous ice fields. In the oceans washing these inhospitable shores, colossal icebergs float (more details:).

Explorers of the North and South Pole

Reach North or South Pole has long been a man's daring dream. Brave and tireless Arctic explorers have made these attempts more than once.

Such was the Russian explorer Georgiy Yakovlevich Sedov, who in 1912 organized an expedition to the North Pole on the ship “St. Foka." The tsarist government was indifferent to this large enterprise and did not provide adequate support to the brave sailor and experienced traveler. Due to lack of funds, G. Sedov was forced to spend the first winter on Novaya Zemlya, and the second on. In 1914, Sedov, together with two companions, finally made his last attempt to reach the North Pole, but the health and strength of this daring man failed, and in March of the same year he died on the way to his goal.

More than once large expeditions on ships to the Pole were equipped, but these expeditions also failed to achieve their goal. Heavy ice “fettered” the ships, sometimes breaking them and carrying them away with their drift far in the direction opposite to the intended path.

Only in 1937, for the first time, a Soviet expedition was delivered by air to the North Pole. The brave four - astronomer E. Fedorov, hydrobiologist P. Shirshov, radio operator E. Krenkel and the old sailor leader of the expedition I. Papanin - lived on a drifting ice floe for 9 months. The huge ice floe sometimes cracked and collapsed. Brave researchers were more than once in danger of dying in the waves of the cold Arctic sea, but, despite this, they carried out their scientific research where no one had ever set foot before. Important research was carried out in the fields of gravimetry, meteorology and hydrobiology. The existence of five climate zones associated with the rotation of the Earth around the Sun has been confirmed.

Many of the features of life familiar to us since childhood are the result of processes on a cosmic scale. The change of day and night, seasons, the duration of the period during which the Sun is above the horizon are associated with how and at what speed the Earth rotates, with the peculiarities of its movement in space.

Imaginary line

The axis of any planet is a speculative construction, created for the convenience of describing movement. If you mentally draw a line through the poles, this will be the Earth's axis. Rotation around it is one of the two main movements of the planet.

The axis does not make 90º with the plane of the ecliptic (the plane around the Sun), but deviates from the perpendicular by 23º27". It is believed that the planet rotates from west to east, that is, counterclockwise. This is what its movement around the axis looks like when observed in the North pole.

Irrefutable proof

It was once believed that our planet was stationary, and the stars fixed in the sky revolved around it. For quite a long time in history, no one was interested in the speed at which the Earth revolves in orbit or around its axis, since the very concepts of “axis” and “orbit” did not fit into the scientific knowledge of that period. Experimental proof of the fact that the Earth is constantly moving around its axis was obtained in 1851 by Jean Foucault. It finally convinced everyone who still doubted this in the century before last.

The experiment was carried out under a dome in which a pendulum and a circle with divisions were placed. Swinging, the pendulum shifted several notches with each new movement. This is only possible if the planet rotates.

Speed

How fast does the Earth rotate on its axis? It is quite difficult to give an unambiguous answer to this question, since the speed of different geographical points is not the same. The closer the area is to the equator, the higher it is. In the Italian region, the speed value, for example, is estimated at 1200 km/h. On average, the planet travels 15º in an hour.

The length of the day is related to the speed of the Earth's rotation. The length of time during which our planet makes one revolution around its axis is determined in two ways. To determine the so-called sidereal or sidereal day, any star other than the Sun is selected as a reference system. They last 23 hours 56 minutes and 4 seconds. If our luminary is taken as the starting point, then the day is called solar. Their average duration is 24 hours. It varies somewhat depending on the position of the planet relative to the star, which affects both the speed of rotation around its axis and the speed at which the Earth rotates in orbit.

Around the center

The second most important movement of the planet is its “circling” in orbit. Constant movement along a slightly elongated trajectory is felt by people most often due to the change of seasons. The speed at which the Earth moves around the Sun is expressed for us primarily in units 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 there is an extra day in February. It represents the sum of hours accumulated during this time that were not included in the accepted 365 days of the year.

Trajectory Features

As already noted, the speed at which the Earth rotates in orbit is associated with the characteristics of the latter. The planet's trajectory differs from an ideal circle; it is slightly elongated. As a result, the Earth either approaches the star or moves away from it. When the planet and the Sun are separated by a minimum distance, this position is called perihelion. The maximum distance corresponds to 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 it is 29.27 km/s, for perihelion it is 30.27 km/s.

Length of day

The speed at which the Earth rotates in its 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 lives. For example, these movements affect the length of the day. The sun constantly changes its position in the sky: the points of sunrise and sunset shift, the height of the star above the horizon at noon becomes slightly different. As a result, the length of day and night changes.

These two values ​​coincide only at the equinox, when the center of the Sun crosses the celestial equator. The tilt of the axis turns out to be neutral with respect to the star, and its rays fall vertically onto the equator. The spring equinox falls on March 20-21, the autumn equinox on September 22-23.

Solstice

Once a year a day reaches its maximum length, and six months later it reaches its minimum. These dates are usually called solstice. Summer falls on June 21-22, and winter falls on December 21-22. In the first case, our planet is positioned in such a way in relation to the star that the northern edge of the axis looks in the direction of the Sun. As a result, the rays fall vertically onto and illuminate the entire region beyond the Arctic Circle. In the Southern Hemisphere, on the contrary, the sun's rays reach only the area between the equator and the Arctic Circle.

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

Seasons

Orbital position affects more than just how fast the Earth moves around the Sun. As a result of changes in the distance separating it from the star, as well as the tilt of the planet’s axis, solar radiation is distributed unevenly throughout the year. And this, in turn, causes the change of seasons. Moreover, the duration of the winter and summer half-years is different: the first is 179 days, and the second - 186. This discrepancy is caused by the same tilt of the axis relative to the plane of the ecliptic.

Light belts

The Earth's orbit has another consequence. The annual movement leads to a change in the position of the Sun above the horizon, as a result of which belts of illumination are formed on the planet:

Hot regions are located on 40% of the Earth's territory, between the Southern and Northern Tropics. As the name suggests, this is where most of the heat comes.

Temperate zones - between the Arctic Circle and the Tropics - are characterized by a pronounced change of seasons.

The polar zones, located beyond the Arctic Circles, are characterized by low temperatures throughout the year.

The movement of planets in general and, in particular, the speed at which the Earth orbits, also influence other processes. Among them are the flow of rivers, the change of seasons, and 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 rotation of the Earth, what is its distance to the Sun, and other features related to the movement of the planet are studied in school. However, if you think about it, they are not at all obvious. When such a thought comes to mind, I would like to sincerely thank those scientists and researchers who, largely thanks to their extraordinary minds, 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.

Today no one has any doubts about the fact that the Earth rotates both around its axis and around the Sun, our natural luminary. This is an absolute and proven fact, but why does the Earth spin the way it does? We will look into this issue today.

Why does the Earth spin on its axis?

We will start with the very first question, which is the nature of the independent rotation of our planet.

And the answer to this question, like many other questions about the secrets of our universe, is the Sun. It is the impact of the Sun's rays on our planet that sets it in motion. If we delve a little deeper into this issue, it is worth noting that the sun's rays warm the atmosphere and hydrosphere of the planet, which are set in motion during the heating process. This movement is what makes the Earth move.

As for the answer to the question of why the Earth rotates counterclockwise and not clockwise, there is no factual confirmation of this fact as such. However, it is worth noting that most bodies in our solar system rotate precisely in a counterclockwise direction. That is why this condition also affected our planet.

In addition, it is important to understand that the Earth rotates counterclockwise only if its movement is observed from the north pole. In the case of observations from the south pole, rotations will occur differently - clockwise.

Why does the Earth revolve around the Sun

As for the more global issue related to the rotation of our planet around its natural star, we examined it in as much detail as possible within the framework of the corresponding article on our website. However, in short, the reason for this rotation is the law of universal gravitation, which acts in Space as on Earth. And it lies in the fact that bodies with greater mass attract less “weighty” bodies. Thus, the Earth is attracted to the Sun and rotates around the star due to its mass, as well as acceleration, moving strictly along the existing orbit.

Why does the Moon revolve around the Earth

We have also already considered the nature of rotation of the natural satellite of our planet, and the reason for such movement is of a similar nature - the law of universal gravitation. The Earth, of course, has more mass than the Moon. Accordingly, the Moon is attracted to the Earth and moves along its orbit.

Basic movements of the Earth in space

© Vladimir Kalanov,
website"Knowledge is power".

Our planet rotates around its own axis from west to east, that is, counterclockwise (when viewed from the North Pole). An axis is a conditional straight line crossing the globe in the region of the North and South Poles, that is, the poles have a fixed position and “do not participate” in rotational motion, while all other location points on the earth’s surface rotate, with a linear rotation speed of surface of the globe depends on the position relative to the equator - the closer to the equator, the higher the linear speed of rotation (let us explain that the angular speed of rotation of any ball is the same at its various points and is measured in rad/sec, we are discussing the speed of movement of an object located on surface of the Earth and the higher it is, the further the object is removed from the axis of rotation).

For example, at the mid-latitudes of Italy the rotation speed is approximately 1200 km/h, at the equator it is maximum and amounts to 1670 km/h, while at the poles it is zero. The consequences of the Earth's rotation around its axis are the change of day and night and the apparent movement of the celestial sphere.

Indeed, it seems that the stars and other celestial bodies of the night sky are moving in the opposite direction to our movement with the planet (that is, from east to west). It seems that the stars are around the North Star, which is located on an imaginary line - a continuation of the earth's axis in a northerly direction. The movement of the stars is not proof that the Earth rotates around its axis, because this movement could be a consequence of the rotation of the celestial sphere, if we assume that the planet occupies a fixed, motionless position in space, as was previously thought.

Day. What are sidereal and solar days?

A day is the length of time during which the Earth makes a complete revolution around its own axis. There are two definitions of the concept “day”. A “solar day” is a period of time for the Earth’s rotation, in which the Sun is taken as the starting point. Another concept is “sidereal day” (from lat. sidus- Genitive sideris- star, celestial body) - implies another starting point - a “fixed” star, the distance to which tends to infinity, and therefore we assume that its rays are mutually parallel. The length of the two types of days differs from each other. A sidereal day is 23 hours 56 minutes 4 seconds, while the duration of a solar day is slightly longer and is equal to 24 hours. The difference is due to the fact that the Earth, rotating around its own axis, also performs an orbital rotation around the Sun. It's easier to figure this out with the help of a drawing.

Solar and sidereal days. Explanation.

Let's consider two positions (see figure) that the Earth occupies when moving along its orbit around the Sun, “ A" - the observer's place on the earth's surface. 1 - the position that the Earth occupies (at the beginning of the countdown of the day) either from the Sun or from any star, which we define as the reference point. 2 - the position of our planet after completing a revolution around its own axis relative to this star: the light of this star, and it is located at a great distance, will reach us parallel to the direction 1 . When the Earth takes its position 2 , we can talk about “sidereal days”, because The Earth has made a full revolution around its axis relative to the distant star, but not yet relative to the Sun. The direction of observing the Sun has changed somewhat due to the rotation of the Earth. In order for the Earth to make a full revolution around its own axis relative to the Sun (“solar day”), you need to wait until it “turns” about 1° more (equivalent to the Earth’s daily movement at an angle - it travels 360° in 365 days), this It will take just about four minutes.

In principle, the duration of a solar day (although it is taken to be 24 hours) is not a constant value. This is due to the fact that the Earth's orbital movement actually occurs at a variable speed. When the Earth is closer to the Sun, its orbital speed is higher; as it moves away from the sun, the speed decreases. In this regard, a concept such as "average solar day", precisely their duration is twenty-four hours.

In addition, it has now been reliably established that the period of rotation of the Earth increases under the influence of the changing tides caused by the Moon. The slowdown is approximately 0.002 s per century. The accumulation of such, at first glance, imperceptible deviations means, however, that from the beginning of our era to the present day, the total slowdown is already about 3.5 hours.

Revolution around the Sun is the second main movement of our planet. The earth moves in an elliptical orbit, i.e. the orbit has the shape of an ellipse. When the Moon is in close proximity to the Earth and falls into its shadow, eclipses occur. The average distance between the Earth and the Sun is approximately 149.6 million kilometers. Astronomy uses a unit to measure distances within the solar system; they call her "astronomical unit" (a.e.). The speed at which the Earth moves in orbit is approximately 107,000 km/h. The angle formed by the earth's axis and the plane of the ellipse is approximately 66°33", and is maintained throughout the entire orbit.

From the point of view of an observer on Earth, the revolution results in the apparent movement of the Sun along the ecliptic through the stars and constellations represented in the Zodiac. In fact, the Sun also passes through the constellation Ophiuchus, but it does not belong to the Zodiac circle.

Seasons

The change of seasons is a consequence of the Earth's revolution around the Sun. The reason for seasonal changes is the inclination of the Earth's rotation axis to the plane of its orbit. Moving along an elliptical orbit, the Earth in January is at the point closest to the Sun (perihelion), and in July at the point farthest from it - aphelion. The reason for the change of seasons is the inclination of the orbit, as a result of which the Earth tilts towards the Sun with one hemisphere and then the other and, accordingly, receives a different amount of sunlight. In summer, the Sun reaches the highest point of the ecliptic. This means that the Sun makes its longest movement over the horizon during the day, and the length of the day is maximum. In winter, on the contrary, the Sun is low above the horizon, the sun's rays fall on the Earth not directly, but obliquely. The day length is short.

Depending on the time of year, different parts of the planet are exposed to the sun's rays. The rays are perpendicular to the tropics during the solstice.

Seasons in the Northern Hemisphere

Annual movement of the Earth

Determining the year, the basic calendar unit of time, is not as simple as it seems at first glance, and depends on the chosen reference system.

The time interval during which our planet completes its orbit around the Sun is called a year. However, the length of the year varies depending on whether the starting point is taken to measure it infinitely distant star or Sun.

In the first case we mean “sidereal year” (“sidereal year”) . It is equal 365 days 6 hours 9 minutes and 10 seconds and represents the time required for the Earth to completely revolve around the Sun.

But if we measure the time required for the Sun to return to the same point in the celestial coordinate system, for example, at the vernal equinox, then we get the duration "solar year" 365 days 5 hours 48 minutes 46 seconds. The difference between the sidereal and solar years occurs due to the precession of the equinoxes; every year the equinoxes (and, accordingly, the sun stations) come “earlier” by approximately 20 minutes. compared to the previous year. Thus, the Earth moves around its orbit a little faster than the Sun, in its apparent movement through the stars, returns to the vernal equinox.

Considering that the duration of the seasons is in close connection with the Sun, when compiling calendars, it is taken as a basis "solar year" .

Also in astronomy, instead of the usual astronomical time, determined by the period of rotation of the Earth relative to the stars, a new uniformly flowing time, not related to the rotation of the Earth and called ephemeris time, was introduced.

Read more about ephemeris time in the section: .

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Our planet is in constant motion, it rotates around the Sun and its own axis. The Earth's axis is an imaginary line drawn from the North to the South Pole (they remain motionless during rotation) at an angle of 66 0 33 ꞌ relative to the plane of the Earth. People cannot notice the moment of rotation, because all objects move in parallel, their speed is the same. It would look exactly the same as if we were sailing on a ship and did not notice the movement of objects and objects on it.

A full revolution around the axis is completed within one sidereal day, consisting of 23 hours 56 minutes and 4 seconds. During this period, first one or the other side of the planet turns towards the Sun, receiving different amounts of heat and light from it. In addition, the rotation of the Earth around its axis affects its shape (flattened poles are the result of the planet’s rotation around its axis) and the deviation when bodies move in the horizontal plane (rivers, currents and winds of the Southern Hemisphere deviate to the left, of the Northern Hemisphere to the right).

Linear and angular rotation speed

(Earth Rotation)

The linear speed of rotation of the Earth around its axis is 465 m/s or 1674 km/h in the equator zone; as you move away from it, the speed gradually slows down, at the North and South Poles it is zero. For example, for citizens of the equatorial city of Quito (the capital of Ecuador in South America), the rotation speed is exactly 465 m/s, and for Muscovites living at the 55th parallel north of the equator, it is 260 m/s (almost half as much) .

Every year, the speed of rotation around the axis decreases by 4 milliseconds, which is due to the influence of the Moon on the strength of sea and ocean tides. The Moon's gravity "pulls" the water in the opposite direction to the Earth's axial rotation, creating a slight frictional force that slows the rotation speed by 4 milliseconds. The speed of angular rotation remains the same everywhere, its value is 15 degrees per hour.

Why does day give way to night?

(The change of night and day)

The time for a complete revolution of the Earth around its axis is one sidereal day (23 hours 56 minutes 4 seconds), during this time period the side illuminated by the Sun is first “in the power” of the day, the shadow side is under the control of the night, and then vice versa.

If the Earth rotated differently and one side of it was constantly turned towards the Sun, then there would be a high temperature (up to 100 degrees Celsius) and all the water would evaporate; on the other side, on the contrary, frost would rage and the water would be under a thick layer of ice. Both the first and second conditions would be unacceptable for the development of life and the existence of the human species.

Why do the seasons change?

(Change of seasons on Earth)

Due to the fact that the axis is tilted relative to the earth's surface at a certain angle, its parts receive different amounts of heat and light at different times, which causes the change of seasons. According to the astronomical parameters necessary to determine the time of year, certain points in time are taken as reference points: for summer and winter these are the Solstice Days (June 21 and December 22), for spring and autumn - the Equinoxes (March 20 and September 23). From September to March, the Northern Hemisphere faces the Sun for less time and, accordingly, receives less heat and light, hello winter-winter, the Southern Hemisphere at this time receives a lot of heat and light, long live summer! 6 months pass and the Earth moves to the opposite point of its orbit and the Northern Hemisphere receives more heat and light, the days become longer, the Sun rises higher - summer comes.

If the Earth were located in relation to the Sun in an exclusively vertical position, then the seasons would not exist at all, because all points on the half illuminated by the Sun would receive the same and uniform amount of heat and light.