The movement of the planet in orbit is determined by two reasons:
- linear inertia of motion (it tends to rectilinear - tangential)
and the gravitational force of the Sun.

It is the force of gravity that will change the direction of movement from linear to circular. And gravitational forces applied to a smaller radius will act
stronger on the planet.
If we consider gravity as a force applied to the center, then this gives a change in the direction of movement to a circular one.
If we consider gravity as the sum of forces applied to the entire mass of the planet,
then this gives both a change in the motion vector to a circular one and rotation around an axis.

Look at the picture.
The planet has points located closer to the Sun and points more distant.
Point A will be closer to the Sun than point B.
And the attraction of point A will be greater than that of point B. Recall that the force of gravity depends on the radius squared.
When the planet moves clockwise, the gravitational force through point A will pull the planet away more than through point B. This difference in gravitational forces applied to diametrically opposite points of the planet, with simultaneous movement, creates rotation.

Thus, the period of revolution of the planet around its axis directly depends on the equatorial radius of the planet.
With large planets such as Jupiter and Saturn, the difference in the attraction of opposite points is greater and the planet rotates faster.

Table of solar days for planets and equatorial radius:
t r
Mercury..... - 175.9421 .... - 0.3825
Venus..... - 116.7490 .....-0.9488
Earth...... - 1.0 .... .. - 1.0
M a r s.... - 1.0275 ... ... - 0.5326
Jupiter..... - 0.41358 ... - 11.209
Saturn..... - 0.44403 .... - 9.4491
U r a n..... - 0.71835 ... - 4.0073
Neptune..... - 0.67126 ... - 3.8826
Pluto..... - 6.38766 .... - 0.1807

The first number is the period of rotation of the planet around its axis in Earth days, the second number is similar - the equatorial radius of the planet. And it is clear that the largest planet, Jupiter, rotates the fastest, and the smallest, Mercury, rotates the slowest.

In general, the reason for the rotation of the Earth can be explained simply.
As the planet moves in orbit, there is a constant change in the direction of its motion from straight to circular. And at the same time, a simultaneous rotation of the planet occurs, due to the fact that the points of attraction of planets located closer to the Sun will pull the planet more strongly than those further away.

For example, on Jupiter, where the planet is not a monolith, rotation occurs in layers. The equatorial movement of the layers is especially noticeable. And, interestingly, there is a reverse movement of some apparently lighter layers, which are replaced by harder and more massive layers.

Reviews

Dear Nikolay!
There is no gravity. Newton's and Einstein's laws do not work.
Using such methods, it is impossible to substantiate the causes of rotation.
But the topic is interesting.
I hope that through joint efforts, and not on this site, we will solve it.

No. Gravity is all there! But we have not yet established the reasons for its appearance.
“Gravitational force,” a term conventionally accepted hereinafter, means an external influence on the body. Conventionally, in physics this is called the “force” of gravity.

And rotation occurs from the action of two forces: the inertia of rectilinear motion and its change to circular motion under the influence of the force of gravity, which in vector is perpendicular to the vector of inertia.

Dear Nikolay!

Dear Nikolay!
Your works already contain calculations, I won’t say, that substantiate the absence of gravity. These works aroused my interest in you, because it is clear that there is a large statistical material and on it, together and quickly we will build a science for ourselves, where many things will fall into place. And whether they accept it or not, it shouldn’t concern us. Let Volosatov prove it, and we will do it.

I can formulate my position on gravity like this.
Gravity, as an attractive force that arises between two bodies, does not exist.
There is an external influence on bodies, the consequence of which is the appearance of force, causing them to move towards each other. Force does not lead to the appearance of another force, but to movement. In this case, the vector of this force is directed along the line connecting these two bodies.
Not attraction, but movement towards.
And not the force arising in the bodies themselves, but the force of external influence.
Like the wind blows on a sail.
In general, I understand force as a factor of external influence.

Dear Nikolay!
Having refuted the forces and their reactions, you return to them again.
Yes, these are the “weights” of our teachings. It’s difficult to break away from them. I am still tearing myself away from the remnants of the teachings of the “institute”. But the physics of the world is completely different. You intuitively felt it. The rest is in personal correspondence.

An indisputable fact is the relative motion of the Earth - the Sun. But the question is, what is moving around what?

Copernicus explained: “We are sliding in a boat along a calm river, and it seems to us that the boat and we are not moving in it, and the banks are “floating” in the opposite direction, in the same way it only seems to us that the Sun is moving around the Earth. But in fact, the Earth is moving around the Earth. everything that is in it moves around the Sun and makes a full orbit within a year.”(L1 p.21) When I was rafting down the river, the banks stood still, and I sailed in a boat past the banks. Everything in the world is relative, either I move relative to the shore, or the shore relative to me. However, the truth is that the water of the river flows relative to the banks. “It is true that Copernicus could not provide direct evidence of the rotation of the Earth and its annual revolution around the Sun, since the level of development of science at that time did not allow this, but the ingeniously simple explanation of the visible movement of the Sun and planets convinced of the validity of his theory.”(L2 p.84) We must pay tribute to Copernicus, he managed to convince many.

The main evidence that the Earth revolves around the Sun is a phenomenon called the annual parallax of nearby stars.

"If you move along the basis AB in Fig. 1, it will seem that the object is displaced against the background of more distant objects. This apparent displacement of an object caused by the movement of the observer is called parallax, and the angle at which the basis is visible from an inaccessible object is called parallax. Obviously, the further away the object is (with the same basis), the lower its parallax...
Even the celestial bodies closest to us are at extremely large distances from the Earth. Therefore, to measure their parallactic displacement a very large basis is required.
When an observer moves across the earth’s surface over distances of thousands of kilometers, a noticeable parallactic displacement of the Sun, planets and other bodies of the solar system occurs.”(L3 p.30) " If you went from Moscow to the North Pole and observed the sky along the way, you would very easily notice that the North Star (or the Pole of the World) is rising higher and higher above the horizon. At the North Pole itself, the stars are located completely differently than in the Moscow sky.”(L1)

Surprisingly, the observer has shifted several thousand kilometers in the orbital plane, sees a change in the celestial sphere, and having shifted in the same plane by almost 300 million kilometers in 6 months, the basis has increased almost 100,000 times, and observes the same insignificant changes. Why? The distances from the Earth to the stars are vast and different, so such a movement in the orbital plane would cause significant changes in the position of the stars in the sky. Parallax is good for characterizing the visual relative motion of objects fixed on the Earth, since it is known what moves and what stands, and in space stars can have their own orbits. Parallax is what it seems to you, so it is not a reliable estimate of what is happening in space. And the ecliptic can be observed both when the Earth rotates around the Sun, and when the Sun rotates around the Earth.

Let me give you an example of relative motion. There are two trains. You are in one of them. Seeing the window, one of them began to move. Which? You look out the window, look at the ground, and it becomes clear to you which train is moving, since you have another point of relative movement, by which you can judge the relative movement of the trains. There is no such point in space between the Earth and the Sun.

Since, from the above, doubts arose about the correctness of Copernicus’s assumption, to determine what revolves around what, I used reliable facts of measuring the daily time of the Earth’s rotation around its axis using the stars and the Sun.

“The simplest time counting system is called sidereal time. It is based on the rotation of the Earth around its axis, which can be considered uniform, since the detected deviations from uniform rotation do not allow 0.005 seconds per day ”(L2 p. 46). The daily time according to the stars is 23 hours 56 minutes 4 seconds. "…

To measure Time, the average solar day began to be used, and since the average Sun is fictitious point, its position in the sky calculated theoretically, based on many years of observations of the true Sun.

The difference between mean and true solar Time is called the equation of time. Four times a year the equation of time is zero, and its maximum and minimum values ​​are approximately +15 min" (L4) Fig.2. " The largest discrepancies occur on February 12 (η = +14 m 17 s) and November 3 – 4 (η = -16 m 24 s)"(L2 p52) .

Rice. 2 . Equation of time

Equation of time - the difference between the time shown by a regular clock and the time shown by a sundial.

" The equation of time changes throughout the year in such a way that it is almost exactly the same from one year to the next. Apparent time, and the sundial, can be ahead (fast) by as much as 16 minutes33 sec(around November 3), or behind (slowly) for as much as 14 minutes 6 seconds (around February 12).'' (L5)

‘’ The connection between both solar time systems is established through the equation of time (ŋ), which is the difference between mean time and solar time

ŋ =T λ - T ¤ (3.8) ‘’ (L2 p.52)

Therefore, to determine the true solar time of day when calculating, I add the time from the time equation for a given day to the average solar time. Just as it is said in the textbook and follows from the definition of the equation of time.

The average day according to the Sun contains 24 hours ( L2 Page 51). Therefore, observer H2 (Fig. 4) on February 12 will record a complete revolution around the Sun in 24 hours 14 minutes 17 seconds.3 – 4 November, observer H2 will determine the daily time from the Sun 24h16m24s = 23 hours 43 minutes 36 seconds.
I suggest for comparative analysis place two observers on the equator, the distance between them is 180 0. They measure daily time simultaneously.

Perhaps it is worth noting here that the Earth is akin to a wheel. The rim is the equator, the axis is the imaginary axis of the Earth. To understand why I placed observers at the equator at a distance of 180 0, considermeasuring the time of a rotating wheel (Fig. 3).

Fig.3

In Fig.4. The star, the Earth, the Sun and observers at the beginning of the daily time count are on the same straight line ZD . H1 measures daily time by the star, H2 by the Sun.
Fig.4

If Copernicus' theory is correct, theno Due to the Earth's orbital motion, H1 will be the first to determine the daily time, and H2 will always be the second. Confirmation of this L2 p.50. “After the sidereal day, the Earth will rotate 360 ​​0 and move along its orbit by an angle of ≈1 0.

In order for...true noon to come again, the Earth needs to rotate another angle of ≈1 0, which will require about 4 m. Thus, the duration of a true solar day corresponds to the rotation of the Earth by approximately 361 0. " Since the distance to the stars is considered unimaginably large, we will assume that∠ O"ZO (Fig. 4) tends to zero, Otherwise there is no way to explain why the stars make a 360 rotation 0 . According to the Earth's orbital motion, it should be smaller. It should be noted that the Earth will make a full revolution when the straight line on which the observers are located becomes parallel to the straight line ZD, since by the beginning of the countdown, observers H1 and H2 are on the straight line ZD. Therefore, observer H1, we will assume, will move to the point “A” will mark the time of the Earth’s complete rotation around its axis relative to the star. Observer H2 will be at point "B". In order for H2 to record the daily time according to the Sun, the Earth must turn to∠BO "D (Fig.4). Once AB is parallel ZD then ∠ BO " D = ∠ O "DO. In other words,the angular distance of the Earth's orbital movement in 23 hours 56 minutes 4 seconds is exactly the angle through which the Earth must rotate for H2 to complete the measurement of daily time according to the Sun.

To answer the question of what revolves around what, I used the theorem: If two parallel lines are intersected by a third line, then the intersecting interior angles are equal.

To overcome ∠ VO" D (Fig. 4) February 12 will take time 24h14m17s – 23h56m4s = 18m13s. What corresponds to the rotation of the Earth by an angle 18m13s / 4m ≈ 4.5O. This means that on this day the Earth moves in orbit at an angle of 4.5 o? Or slows down the speed of rotation around its axis for the period of overcoming∠ VO" D , because according to the theory, the Earth cannot travel in orbit more than ≈1 o per day. November 3-4 will spend 12 minutes. 28sec. time is less than H1 according to the stars. For this to happen, the Earth would first have to move in orbit in the opposite direction. It is impossible to simulate the rotation of the Earth around the Sun, according to the equation of time, without changing the direction of motion in orbit and the speed of rotation of the Earth around its axis, since such changes in the Earth’s movement are unnoticed.

In Fig. 5, since during the year the accuracy of measuring the daily time by stars does not exceed 0.005 seconds, for a comparative analysis the method of graphically superimposing three pronounced results of the daily time on each other, obtained by simultaneously measuring the daily time by the stars and the Sun, was used.

H1 – H2 are the positions of daily time observers according to the stars and the Sun, respectively.

D 1 – the position of the Sun, the equation of time is zero, ŋ=0

C, A, B - the position of observer H2 on these days at the end of the measurement of daily time by the Sun.

Fig.5

Earth, Star Z, Sun D and H1, H2 at the beginning of the countdown are on the same straight line ZD . In all cases, the beginning and end of the measurement of daily time by the stars, when the Earth makes a revolution of 360 0, are on the same straight line ZD. As you can see (Fig. 5), the Sun relative to the Earth changes its direction of movement, which is confirmed by the equation of time (Fig. 2).

The main thing in Copernicus' theory is that the Sun is motionless and the Earth revolves around it. This statement is refuted by the facts listed above. The incompatibility of the theory with the obtained results of measuring daily time using the stars and the Sun is obvious. It follows that Ptolemy is right. The Earth does not revolve around the Sun.

The question arises, which model of the relative motion of the Earth-Sun will correspond to the facts listed above, the rotation of the Earth by 360 0 around its axis relative to the stars, different values ​​of the true day according to the Sun throughout the year. Each of the planets, according to Ptolemy, moves around a certain point. This point, in turn, moves in a circle, in the center of which is the Earth.

Fig.6Fig.7

Let us apply this assumption to simulate the movement of the Sun around the Earth. The rotation of the Sun around the Earth, shown in Fig. 6, removes all the contradictions that arose when considering the theory of the Earth's rotation around the Sun. Dot " W "orbits around the Earth, and around this point" W "The Sun rotates. The Sun moves in orbit around a point" W ", speed relative to the Earth when moving in the direction of the point's orbit " W "increases, and when moving to meet the orbit of the point" W ", decreases and becomes inverse. Therefore, throughout the year, there is a decrease or increase in the true daily time of the Sun relative to the sidereal day.

The sun revolves around the Earth!

Knowing about the change in temperature cycles on Earth, we can assume (Fig. 7) that the Sun rotates around the orbit of point “W” (“barrel”, aerobatics) for 11 years, and the Earth rotates around point “G” in 100 years. At the same time, the Earth changes the inclination of its orbit to the orbit of the point " W ", around which it revolves, over a very long period of time, say 1000 years or more.

Simulator of the rotation of the Sun around the Earth

Direct evidence that the Earth is inside the orbit of the Sun is not only The Equation of Time, but also the Analemma of the Sun. It is worth recalling that:Sine wave- a transcendental flat curved line resulting from double uniform motion of a point - forward and reciprocating in a direction perpendicular to the first.Sine wave - function graphat=sinx, continuous curved line with periodT=2p.

From the point of view of the sinusoidal oscillation of the Equation of Time, the Sun makes two revolutions around the energy point " W " But the orbital movement of the point " W ” and the Sun are carried out in the same direction. Therefore, in fact, the Sun makes three revolutions per year around the point " W " Unfortunately, it is impossible to make a scale model of the movement of the Sun around the Earth. Scale implies maintaining the ratio of sizes, but creating a simulator that explains that the analemma is obtained due to the movement of the Sun in its orbit around the Earth is quite acceptable. Figure 8 shows such a simulator.

Fig.8

1 - simulator of a small solar orbit.
2 - energy point ‘W’ (aka orbital axis 1).
3 - Sun simulator,
4 - rotation scale of the Sun simulator (graduation in degrees).
5 - tripod.
6 - camera.
7 - tablet on which the camera is mounted.
8 - tripod axis (tilt 23 0 26’).
9 - tripod rotation arrow.
10 - scale of rotation of the tablet and tripod (graduation in degrees).
11 - tablet axis (imaginary axis of the Earth).
12 - base of the simulator.

Since a photograph of the analemma (Fig. 9) is taken after a certain number of days at the same hour of the day, the camera (7) and tripod (5) rotate together. Pictures are taken on the simulator as follows: the tripod is rotated counterclockwise by 10 0, and the small solar orbit simulator (1) is rotated by 30 0. Thus, taking 36 frames per frame, you get an analemma. Of course, not all facts are taken into account here, such as the latitude of the camera and refraction. Yes, this is not necessary. The fact itself is important The analemma is obtained from the rotation of the Sun around the point " W" and dots '' W '' around the Earth.

Fig.9

Afterword

When I accidentally began researching this issue, I discovered that the Earth cannot revolve around the Sun.

I published three articles on the Internet, “Copernicus is great, but truth is more valuable,” “Copernicus’s assumption and reality,” “Ptolemy is right. The sun revolves around the Earth.”In the first article, I tried to determine the distance to the star taken to measure daily time, since the following data is known: sidereal day 23 hours 56 minutes 4 seconds. (86,164sec.); average solar day is 24 hours (86,400 seconds); the radius of the Earth at the equator is 6378160 m; the average speed of the Earth in orbit is 29.8 km/sec. (29,800 m/sec.); linear speed at the equator is 465m/sec. I assumed that the error would be negligible if I neglected the curvature of the Earth and orbit. The calculation amazed me. It turned out that the distance to the star taken to measure daily time is the same as to the Sun and cannot be different. I wrote to the Institute of Astronomy. They answered, read textbooks on Astronomy and that there is a phenomenon of parallax, which is evidence of the rotation of the Earth around the Sun. I started reading. Excerpts that seem to be ignored and which caused me to doubt the correctness of Copernicus’ theory,is in the second article and in this one. The question arose: is it even possible to determine who is right? Copernicus or Ptolemy. Ptolemy was mistaken in believing that the Earth is the center of the universe, but the center of the solar system is quite acceptable.

In the second article I proved that the Earth rotates according to the stars360 0 . but one of the proofs that the Earth cannot rotate around the Sun was the article by L.I. Alikhanov, which states that the reflected laser signal from a reflector located on the Moon cannot return to the place from which it was sent. Unfortunately it can. You just need to introduce a correction by installing a reflector. In the same article I provided a graph‘’ Equations of time’’ . The graph surprised me by its similarity to sinusoidal oscillations, reflecting movement in a circle. Wrote a letter to the Academy of Sciences. An answer came from the same institute under the same number, although the years were different. I understand them. There are many who want to refute theories and laws, so they imprisoned an employee, and he rivets answers on behalf of the INASAN expert group, so why bother? Maybe they are right. We're flying into space. Well, it turned out that the distance to the stars is 20-25 thousand times closer, but still far away, which makes no one hot or cold. Although, knowing what revolves around what and how, you can make weather forecasts for more than one year.

Lovers of the search for truth, in their free time from work, have one advantage, which is also their disadvantage: they are not burdened with knowledge. But therefore they can make extraordinary assumptions, which should not be brushed aside like annoying flies. We need to figure out what they are right or wrong about. Professionals are often prevented from delving into the works of amateurs due to their conviction that encyclopedic authorities are right. But nothing lasts forever. Theories do not last forever.

The only reliable evidence of what it revolves around can, at the moment, only be Equation of time And Analemma of the Sun, which became the main evidence in this article.

Everything in the world is relative. However, no one would think of saying that the Earth moves relative to the Moon. The Moon moves relative to the Earth against the background of stars. The Sun also moves along the ecliptic against the background of stars. However, the small gravitates toward the big, so it is believed that the Earth rotates around the Sun, but measurements of daily time from the stars and the Sun indicate the opposite.I believe that the Earth is close to a point of increased gravity, so its orbit is inside the orbit of the Sun.

Take a magnet, bring a nail to it, and without even touching the magnet, the nail will begin to have the properties of a magnet. I assume that the universe is something like a collection of gravitational fields (galaxies are flat). Planets and stars being in this field, under its influence, acquire their own gravity, depending on their physical properties. The fields have quiet zones and points with concentrated gravity. The planets of the solar system rotate around such a gravitational charge. I wrote this assumption because I think it explains why the Sun revolves around the Earth.

To answer the question posed to yourself, why is daily time stable according to the stars, but not according to the Sun? I think I managed to answer. - The sun revolves around the Earth.

S.K. Kudryavtsev

For a very long time, people thought that our planet was flattened and rested on 3 pillars. A person is unable to notice its rotation while standing on it. The reason for this is the size. They make a huge difference! The size of a person is too insignificant in relation to the size of the globe. Time moved forward, science progressed, and with it people’s ideas about their own planet.

What have we come to today? Is it true that and not the other way around? What other astronomical knowledge is valid in this area? First things first.

Along its axis

Today we know that it simultaneously takes part in two types of motion: the Earth rotates around the Sun and along its own imaginary axis. Yes, exactly the axles! Our planet has an imaginary line that “pierces” the surface of the earth at its two poles. Draw your axis mentally into the sky, and it will pass next to the North Star. That is why this point always seems motionless to us, and the sky seems to be rotating. We think that they are moving from east to west, but we note that it only seems to us! Such movement is visible, since it is a reflection of the planet’s real rotation - along the axis.

The daily rotation lasts exactly 24 hours. In other words, in one day the globe makes one full circle along its own axis. Each of the earth's points first passes through the illuminated side, then through the dark side. And a day later everything repeats again.

For us, it looks like a constant change of days and nights: morning - day - evening - morning... If the planet did not rotate in this way, then on the side facing the light there would be eternal day, and on the opposite side there would be eternal night. Horrible! It's good that this is not the case! In general, we figured out the daily rotation. Now let's find out how many times the Earth revolves around the Sun.

Sunny "round dance"

We also won’t notice this with the naked eye. However, this phenomenon can be felt. We all know very well the warm and cold seasons of the year. But what do they have in common with the movements of the planet? Yes, they have everything in common! The Earth revolves around the Sun in three hundred and sixty-five days, or one year. In addition, our globe is a participant in other movements. For example, together with the Sun and its “colleagues” the planets, the Earth moves relative to its own galaxy - the Milky Way, in turn, moving relative to its “colleagues” - other galaxies.

It is important to know that in the entire Universe nothing is stationary, everything flows and changes! Let us note that the movement of the celestial body we see is just a reflection of a rotating planet.

Is the theory correct?

Today, many people are trying to prove the opposite: they believe that the Earth does not revolve around the Sun, but, on the contrary, the heavenly body revolves around the globe. Some scientists talk about the joint movement of the Earth and the Sun, which occurs relative to each other. Perhaps one day the world's scientific minds will turn all the scientific ideas known today about space upside down! So, all the “i”s are dotted, and you and I learned that around the Sun (at a speed, by the way, about 30 kilometers per second), and it makes a full revolution in 365 days (or 1 year), at the same time Our planet rotates on its axis every day (24 hours).

The earth does not stand still, but is in continuous movement. Due to the fact that it revolves around the Sun, the planet experiences a change of seasons. However, not everyone remembers that while flying around the heavenly body, the Earth still has time to spin around its own axis. It is this movement that causes the change of day and night outside the window and is called diurnal.

AiF.ru helped to understand how and at what speed the Earth rotates around the Sun and its axis astrophysicist, employee of the Moscow Planetarium Alexander Perkhnyak.

The movement of the Earth around its axis

How does the Earth rotate on its axis?

As the Earth rotates around its axis, only two points remain stationary: the North and South Poles. If you connect them with an imaginary line, you get the 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.

At what speed does the Earth rotate around its axis?

The Earth rotates around its axis at a speed of 465 m/s, or 1,674 km/h. The farther from the equator, the slower the planet moves.

“Few people know that at a distance from the equator, the Earth’s rotation speed becomes slower. Visually it looks like this. The city of Quito is located near the equator, which means that it and its inhabitants, unnoticed by themselves, make a turn together with the Earth at a speed of 465 m/s. But the rotation speed of Muscovites living much north of the equator will be almost two times less: 260 m/s,” Perkhnyak said.

In which direction does the Earth rotate?

The Earth rotates around its axis from west to east. If you look at the Earth from above in the direction of the North Pole, it will rotate counterclockwise.

Does the speed of the Earth's movement around its axis change?

Yes, it is changing. Every year the Earth's course slows down by an average of 4 milliseconds.

“Astrophysicists associate this phenomenon with lunar gravity, which is known to affect the tides on our planet. So, when they occur, the Moon seems to be trying to attract water to itself, moving it in the direction opposite to the Earth’s movement. Because of this peculiar resistance, a slight frictional force arises at the bottom of reservoirs, which, in accordance with the laws of physics, slows down the speed of the Earth. Insignificant, only 4 milliseconds per year,” Perkhnyak said.

Movement of the Earth around the Sun

How does the Earth revolve around the Sun?

Our planet revolves around the Sun in an orbit more than 930 million km long.

At what speed?

The Earth rotates around the Sun at a speed of 30 km/s, that is, 107,218 km/h.

How long does it take for the Earth to complete a revolution around the Sun?

The Earth completes one full revolution around the Sun in approximately 365 days. The period of time during which the Earth completely revolves around the Sun is called a year.

In which direction does the Earth move when it circles the Sun?

Around the Sun, the Earth rotates from west to east, as well as around its axis.

At what distance does the Earth revolve around the Sun?

The Earth revolves around the Sun at a distance of about 150 million km.

How do the seasons change?

As the Earth rotates around the Sun, its angle of inclination does not change. As a result, in one part of its trajectory the Earth will be turned more towards the Sun with its lower half: the Southern Hemisphere, where summer begins. And at this time the North Pole will be practically hidden from the sun: that means winter is coming there. Twice a year the Sun illuminates the Northern and Southern Hemispheres approximately equally: this is the time of spring and autumn. These moments are also known as the spring and autumn equinoxes.

Why doesn't the Earth fall into the Sun?

“When the Earth revolves around the Sun, a centrifugal force is generated that constantly tries to push our planet away. But she won't succeed. And all because the Earth always moves around the star at the same speed and is at a safe distance from it, comparable to the centrifugal force with which they try to knock the Earth out of orbit. That’s why the Earth doesn’t fall on the Sun and doesn’t fly into space, but continues to move along a given trajectory,” said Alexander Perkhnyak.

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.