The rotation of the sky. The daily rotation of the earth is the greatest mystery. Precession and nutation

Announcement: What is the most basic, the earliest factor in the historical hierarchy of development and progress, without which life itself could not have appeared on Earth? I will say right away - this factor is the daily rotation of the Earth around its axis! Without daily rotation, life could never have appeared on Earth! But the reason for the occurrence of the daily rotation of the Earth around its axis has not yet been disclosed, and what spun and continues to rotate our planet, the divine will or the material reason, scientists still do not know.

There are many unsolved mysteries and secrets of the universe, and the more we know the world around us, the more new ideas, riddles and questions appear. But these new mysteries in the hierarchy of development are more recent, i.e. derived from more important primary forms and laws. And some important primary mysteries, even today, have not yet been solved. For example, what is the most basic, key factor in the historical hierarchy of development and progress, without which life itself could not have appeared on Earth?

I will say right away - one of the most important and greatest factors is the factor of the daily rotation of the Earth. Yes Yes! If there was no daily rotation of the Earth, then life could never have arisen on Earth! And the riddle of the mechanism of occurrence of this rotation has not yet been solved. Let's be aware of some facts: the power of solar radiation when approaching the Earth is huge ~ 1.5 kWh / m2 and without rotation around its axis, one side of the Earth would be heated from the radiation of the Sun, and cosmic cold would reign on its other side! The heat of the Sahara and the cold of Antarctica would be many times stronger! And it was the daily rotation of the Earth that made it possible to make thermal conditions more uniform over millions of years in all regions of the Earth, and this was one of the most important conditions for the emergence of life. Those. The daily rotation of the Earth was the key, the main condition for the emergence of life on Earth.

But how did this diurnal rotation come about? What has untwisted our planet? To date, there is no scientific explanation for this riddle! The very daily rotation of the Earth was scientifically proven by historical standards quite recently, in the period from the 14th to the 16th centuries of our era, along with the creation of the heliocentric system of the world and the discovery of the rotation of the Earth around the Sun. Prior to this, for thousands of years, the idea of ​​the Earth as the immovable center of the whole world dominated. Understanding the issues raised by the theory of the rotating Earth contributed to the discovery of the laws of classical mechanics.

An experiment that clearly demonstrates the rotation of the Earth was set up in 1851 by the French physicist Léon Foucault. Its meaning is very simple and clear. The plane of oscillation of the pendulum is unchanged relative to the fixed stars. And in the reference frame connected with the Earth, the plane of oscillations of the pendulum turns in the direction opposite to the direction of the Earth's rotation, which is clearly seen from the divisions on the circle placed under the pendulum. This effect is most clearly expressed at the poles, where the period of a complete rotation of the pendulum plane is equal to the period of the Earth's rotation around its axis, and at the equator the plane of oscillation of the pendulum is unchanged. At present, the Foucault pendulum is successfully demonstrated in a number of scientific museums and planetariums, in particular, in the planetarium of St. Petersburg, the planetarium of Volgograd.

In recent years, one hypothesis has appeared for the emergence of the Earth's daily rotation from the action of global terrestrial winds and ocean currents, but it does not hold water. After all, water and the atmosphere on Earth appeared much later than the appearance of the daily rotation of the Earth. In addition, scientists have proven that ocean currents appeared precisely due to the daily rotation of the Earth, and not vice versa. The influence of the Moon also could not lead to the appearance of the daily rotation of the Earth. In addition, the Moon has its own rotation. Other planets of the solar system, as well as the Sun itself, rotate around their axis. What causes all these rotations? There is no answer yet. But it is possible that the mechanism for the rotation of the planets and the Sun is the same, since the Sun revolves around the center of the Milky Way galaxy, like planets around the Sun.

By the way, all celestial bodies do not rotate in a circular, but in an elliptical Keplerian orbit, which also shifts in space over time:

Also, there is still no answer to the question of the reason for the appearance of the inclination of the Earth's axis of rotation relative to the plane of rotation of the Earth around the Sun. This tilt is 66˚33’22” and its presence has led to the appearance on Earth of seasons that are extremely important for the Earth’s climate.

The seasons, along with the daily rotation, i.e. the rapid change of day and night, even more softened and facilitated the conditions for the emergence of life and the biosphere of the Earth, for the emergence of numerous forms of plants, animals, and also humans. Together with the seasons, 5 zones of illumination (or radiation) appeared on Earth, limited by the tropics and the polar circles, which are divided by the duration of sunlight and the amount of heat received. Scientists have also noticed that the Earth's axis of rotation periodically changes its direction. This is called precession. Every 13,000 years, the Earth's axis of rotation "tilts" in the opposite direction. But after all, huge celestial bodies rotating in weightlessness are ideal gyroscopes that cannot change their orientation in space.

Only much later than the appearance of daily rotation on Earth did water, an oxygen atmosphere, and then various forms of life, animals, plants, and humans appear.

Another important factor for the emergence of life on Earth is the Earth's magnetic field. Earth's magnetosphere protects all life from solar radiation. But this factor has long found its scientific explanation. Therefore, I will touch on it very briefly.

The sun and each planet of the solar system has its own magnetic field, which creates a special shell around each of these celestial bodies - the magnetosphere. The poles of the Earth's magnetic field are located almost on the axis of the Earth's daily rotation with a slight deviation of 11.5 degrees from it. There are two types of the Earth's magnetic field: constant (main) and variable. Their nature and origin are different, but there is a relationship between them. The formation of a constant magnetic field is promoted by internal sources of the Earth - electric currents that arise on the surface of the compacted core of the Earth due to the difference in temperatures in its parts, which is presumably associated with dynamic processes in the mantle and the core of the Earth. They create a stable magnetic field that extends for 20-25 Earth radii, which is subject only to slow, "secular" fluctuations. A variable field is created when interacting with external sources located outside the planet. An alternating magnetic field is about 100 times weaker than a constant one and is characterized by regular variations, which are mainly of a solar nature, and irregular ones (such as magnetic storms). Near the Earth, the average diameter of the magnetosphere is over 90,000 km perpendicular to the sun's beam. The Earth is constantly exposed to flows of charged particles (corpuscles) of cosmic origin and radiation from the Sun - the solar wind. The magnetosphere under impacts of the solar wind is compressed from the side of the Sun and strongly elongated in the antisolar direction. This is how the tail of the magnetosphere is formed, elongated by 900-1050 Earth radii. The magnetosphere is the main obstacle to the penetration of charged solar particles harmful to living matter into the geographic envelope and thus isolates living organisms from penetrating radiation. Cosmic particles can freely invade the atmosphere only in the region of the magnetic poles. At the same time, the magnetosphere transmits electromagnetic waves to the surface of the planet - X-rays and ultraviolet rays, radio waves and radiant energy, which serves as the main source of heat and energy base for the processes occurring in the geographic shell.


In the historical context, geographic displacements of the magnetic field and even changes in the polarity of the magnetic dipole are observed. Polarity, when the northern end of the magnetic needle is directed to the north, is called direct (as it is now), otherwise they speak of the reverse magnetization of the earth's dipole. Observations of the Earth's magnetic field are conducted by many observatories around the world.

Thus, the rotation of the planets around their axis is the most important and most important condition for the emergence of life on the planets. Finding out the reason for the planets' own rotation will make it possible to understand whether there can be many such planets in the Universe as the Earth, on which life will also appear over time, or whether the Earth is a unique phenomenon in the Universe. The presence of daily rotation in other planets of the solar system hints that the reason for the appearance of such rotation in the planets is not an accident, but some as yet undiscovered objective mechanism that is waiting for its scientific disclosure. This means that the Hierarchy of the laws of the origin and development of the world is only just beginning to be known by man.

Additional information on this topic:

The geographical consequences of the daily rotation of the Earth are:
1. Change of day and night.
2. Deformation of the figure of the Earth.
3. Existence of the Coriolis force acting on moving bodies.
4. The occurrence of ebbs and flows.

« On the cause of the rotation of the Earth and other unexplained phenomena.
space scientist
Date: Sunday, 20.11.2011, 19:55

Causes of the rotation of the starry sky

Why does the starry sky seem to be rotating, and why exactly is the North Star almost motionless? It turns out that the reason for this apparent movement of the stars lies in the rotation of the Earth. Just as a person circling around the room imagines that the whole room is circling around him, so we, who are on the rotating Earth, see as if the stars are moving. It is known from geography that the imaginary axis around which the globe rotates intersects the surface of the Earth at two points. These points are the North and South geographic poles. If the direction of the earth's axis is continued, then it will pass near the North Star. This is why the North Star seems to be almost stationary. It is located at the North Pole of the world.

In the southern starry sky, which is only partially visible in our Northern Hemisphere due to the spherical shape of the Earth, there is a second fixed point - the South Pole of the World - around which the southern stars revolve.

Let us now get acquainted in more detail with the apparent diurnal motion of the stars. Turn your face to the south side of the horizon and watch the movement of the stars. To make these observations more convenient, imagine a semicircle that passes through the zenith (a point directly above your head) and the celestial pole. This semicircle will intersect with the horizon at the point of the north (under the North Star) and at the opposite point of the south. Astronomers call this line the celestial meridian. It divides the sky into eastern and western halves. Watching the movement of stars in the southern part of the sky, we will notice that the stars located to the left of the celestial meridian (that is, in the eastern part of the sky) rise above the horizon. After passing through the celestial meridian and hitting the western part of the sky, they begin to descend towards the horizon.

This means that when they passed through the celestial meridian, at that moment they reached their greatest height above the horizon. Astronomers refer to the passage of a star through its highest position above the horizon as the star's superior culmination.

If you turn your face to the north and watch the movement of the stars in the northern part of the sky, you will notice that the stars passing through the celestial meridian below the North Star, at that moment, are at their lowest position above the horizon. Moving from left to right, they, having passed the celestial meridian, begin to rise. When a star passes through its lowest possible position above the horizon, astronomers say the star is at its lowest climax.

Thus, if a star passes through the line of the celestial meridian between the celestial pole (or approximately the North Star) and the point of the south, then this will be the upper climax of the star.

During the day the sun moves across the sky. It rises, rises higher and higher, then begins to descend and sets. It is easy to see that the stars also move across the sky.

Choose a place for observation from where the sky is clearly visible, and notice from it, over what objects visible on the horizon (houses or trees), the Sun is visible in the morning, at noon and in the evening. Come to this place after sunset, notice the brightest stars in the same sides of the sky and mark the time of observation on the clock. If you come to the same place in an hour or two, then make sure that all the stars you noticed have moved from left to right. So, the star, which was in the direction of the morning Sun, rose in the sky, and the star, which was in the direction of the evening Sun, sank.

Do all stars move across the sky? It turns out that everything, and moreover, at the same time. We can say that the whole sky with the stars on it, as it were, rotates around us every day.

That side of the sky, where the Sun is visible at noon, is called the south, the opposite - the north. Observe in the northern side of the sky, first above the stars close to the horizon, and then above the higher ones. You will see that the higher the stars are from the horizon, the less noticeable their movement is. In the sky you can also find such a star, the movement of which is almost imperceptible throughout the night, and the closer other stars are to this star, the less noticeable their movement is. This star was called the Polaris, we already know how to find it by the stars of Ursa Major.

When we look at the North Star, more precisely, at a fixed point next to it - at the north pole of the world, the direction of our gaze coincides with the direction of the axis of the starry sky. The very axis of rotation of the starry sky is called the axis of the world.

The rotation of the sky around the Earth is an apparent phenomenon. The reason for this is the rotation of the earth. Just as a person whirling around a room imagines that the whole room is spinning around him, so it seems to us, who are on the rotating Earth, that the sky is rotating. In ancient times, observing the daily rotation of the sky, people made a deeply erroneous conclusion that the stars, the Sun and the planets revolve around the Earth every day. In fact, as established in the XVI century. Copernicus, the apparent rotation of the starry sky is only a reflection of the daily rotation of the Earth around its axis. However, the stars do move. Not so long ago, astronomers found that all the stars of our Galaxy move at different speeds around its center (the Galaxy is described in the article “3 Stars and the Depths of the Universe”).

The imaginary axis around which the globe rotates intersects the surface of the Earth at two points. These points are the North and South geographic poles. If we continue the direction of the earth's axis, it will pass near the North Star. That is why the North Star seems to us almost motionless.

In the southern starry sky, which is only partially visible in our northern hemisphere due to the spherical shape of the Earth, there is a second fixed point in the sky - the south pole of the world. The stars of the southern hemisphere revolve around this point.

Let us get acquainted in more detail with the apparent diurnal motion of stars. Turn your face to the south side of the horizon and watch the movement of the stars. To make observations more convenient, imagine a semicircle that passes through the zenith (a point directly above your head) and the celestial pole. This semicircle (celestial meridian) will intersect with the horizon at the point of the north (under the North Star) and at the opposite point of the south. It divides the sky into eastern and western halves. Watching the movement of stars in the southern part of the sky, we will notice that the stars located to the left of the celestial meridian (that is, in the eastern part of the sky) rise above the horizon. After passing through the celestial meridian and hitting the western part of the sky, they begin to descend towards the horizon. This means that when the stars pass through the celestial meridian, they reach their greatest height above the horizon. Astronomers refer to the passage of a star through its highest position above the horizon as the star's superior culmination.

If you turn your face to the north and watch the movements of the stars in the northern part of the sky, you will notice that the stars passing through the celestial meridian below the North Star, at that moment, are at their lowest position above the horizon. moving on

from left to right, they, having passed the celestial meridian, begin to rise. When a star passes through its lowest possible position above the horizon, astronomers say the star is at its lowest climax.

Among the constellations visible in our country, there are those that, moving around the pole of the world, never go beyond the horizon. This is not difficult to verify by observations: in the winter months, the constellation Ursa Major at the time of its lowest position during the day is visible above the horizon.

But not only the Big Dipper turns out to be a non-setting constellation for the inhabitants of the USSR. The stars of Ursa Minor, Cassiopeia, Draco, Cepheus, which are close to the north celestial pole, also never set, for example, beyond the Moscow horizon. These are non-setting stars.

Along with the stars that never set, there are those that never rise over our country. These include many stars in the southern hemisphere of the sky.

The sky, like the globe, is mentally divided into two hemispheres by an imaginary circle, all points of which are at the same distance from the poles of the world. This circle is called the celestial equator. It crosses the horizon line at points east and west.

All stars during the day describe paths parallel to the celestial equator. The hemisphere of the sky in which the North Star is located is called the northern hemisphere, and the other hemisphere is called the southern.

View of the starry sky in different places on Earth

The sky looks different in different parts of the world. It turns out that the view of the starry sky depends on which parallel the observer is on, in other words, what is the geographical latitude of the place of observation. The angular elevation of the pole of the world (or, approximately, the North Star) above the horizon is always equal to the geographical latitude of the place.

If you travel from Moscow to the North Pole, as you go you will notice that the North Star (or the pole of the world) is getting higher and higher above the horizon. Therefore, more and more stars are not setting.

Finally, you have arrived at the North Pole. Here, the arrangement of stars is not at all the same as in the Moscow sky.

The geographic latitude of the North Pole of the globe is 90°. This means that the pole of the world (and the North Star) will be directly above your head - at the zenith. It is not difficult to imagine that the celestial equator here, at the North Pole, will coincide with the horizon line. Thanks to this, at the North Pole you will see an unusual picture of the movement of stars: always moving along paths parallel to the celestial equator, the stars move parallel to the horizon. Here, all the stars of the northern hemisphere of the sky will be non-setting, and the southern - non-rising.

If you now mentally transport yourself from the North Pole to the earth's equator, you will see a completely different picture.

As you move south, the latitude of the place and, consequently, the height of the celestial pole (and the North Star) will begin to decrease, i.e., the North Star will approach the horizon.

When you find yourself on the earth's equator, the geographical latitude of any point of which is equal to zero, you will see the following picture: the north pole of the world will be at the north point, and the celestial equator will become perpendicular to the horizon. At the point of the south will be the south pole of the world, located in the constellation Octant.

All stars at the Earth's equator describe paths perpendicular to the horizon during the day. If there were no Sun, because of which it is impossible to see stars during the day, then during the day at the earth's equator it would be possible to observe all the stars of both hemispheres of the sky.

At different times of the year, different constellations can be observed in the evenings. Why is this happening?

To understand this, make some observations. Shortly after sunset, spot a star in the western sky, low on the horizon, and note its position relative to the horizon. If, about a week later, at the same hour of the day, you try to find this star, you will notice that it has now become closer to the horizon and is almost hidden in the rays of the evening dawn. This happened because the Sun approached this star. And in a few weeks, the star will completely disappear in the sun's rays and it will not be possible to observe it in the evenings. When another 2-3 weeks pass, the same star will become visible in the morning, shortly before sunrise, in the eastern part of the sky. Now the Sun, continuing its movement from west to east, will be east of this star.

Such observations show that the Sun not only moves along with all the stars, rising in the east and setting in the west during the day, but also slowly moves among the stars in the opposite direction (i.e., from west to east), moving from constellation to constellation.

Of course, you will not be able to observe the constellation in which the Sun is currently located, since it rises with the Sun and moves across the sky during the day, that is, when the stars are not visible. The sun with its rays extinguishes the stars not only of the constellation where it is located, but also of all others. Therefore, they cannot be observed.

The path along which the Sun moves among the stars throughout the year is called the ecliptic. It passes through twelve so-called zodiac constellations, each of which the Sun visits for approximately one month each year. The zodiac constellations are called as follows: Pisces (March), Aries (April), Taurus (May), Gemini (June), Cancer (July), Leo (August), Virgo (September), Libra (October), Scorpio (November),

Constellations visible at mid-latitudes in the southern half of the sky in spring.

Sagittarius (December), Capricorn (January), Aquarius (February). In parentheses are the months when the Sun is in these constellations.

The annual motion of the Sun among the stars is apparent. In fact, the observer himself moves along with the Earth around the Sun. If during the year in the evenings we observe the stars, we will find a gradual change in the starry sky and get acquainted with all the constellations that are visible at different times of the year.

Imagine that you are spinning, as you did in childhood. And on the button of your shirt sits a microscopic little man. What will he see and feel?

It will seem to him that the whole furnishings of the room are spinning around him: chairs, a table, a TV set, paintings on the walls, and the relative position of all these objects will remain unchanged ....

And only two points - one point above, on the ceiling, and the other point below, on the floor, will remain motionless.

And if a beloved cat suddenly goes somewhere on his own business, then its location in relation to the home environment will change.

And the most amazing. It will seem to a microscopic man that it is he who is motionless, and everything revolves around him, because people cannot always feel their own movement. For example, it happens that we look out the window of the car and do not know whether it was the neighboring train that has gone, or our train has slowly and smoothly moved off. Another example is when we are sitting in an airplane, we do not feel that we are flying at a speed of a hundred meters per second.

Why all this?

And to the fact that what has been said can be repeated verbatim, if we accept that we are microscopic little men living on the Earth rotating around its axis. The furnishings of the room are, as it were, the stars, the cat is the Moon, two fixed points are the poles of the world.

We live on the Earth rotating around its axis, and it seems to us that the whole sky revolves around us, making a complete revolution in about a day. Therefore, such a rotation is called the daily movement of the sky.

The daily movement is visible to the naked eye: after a couple of hours, the rotation of the sky is literally striking.

And here is a photograph of the sky, taken by a fixed camera, exposure one hour. Almost all the stars turned out in the form of lines, because their position in the sky changed during the time of photographing.

The only star that has remained motionless and looks like a dot in the photograph is the North Star. This is far from the brightest star, which is remarkable in that it is very close to the North Pole of the world - to that point in the sky that remains motionless during the daily movement of the sky.

The diametrically opposite point of the sky, the South Pole of the World, also remains motionless. The South Pole of the world is not visible to us, the inhabitants of the northern hemisphere of the Earth, it is always below the horizon. And in the southern hemisphere of the Earth, on the contrary, only one South Pole of the world is visible.

About distances in the sky.

You can’t put a ruler to the sky, you can’t measure distances in meters or centimeters. You can only measure angles between any two directions.

For example, the angles between any two stars, or the angle between the centers of the disks of the Sun and the Moon, etc.

In particular, the poles of the world are diametrically opposed points, so the angle between them is 180°.

Points that are 90° away from both the North and South Pole of the World make up the celestial equator. Similarly, the points of the earth's equator are equally distant from the poles of the earth.

The celestial equator divides the sky into two halves. That half of the sky, which contains the North celestial pole, is called the northern hemisphere of the sky, and the other, containing the South celestial pole, is called the southern hemisphere. And here, too, a complete analogy with the Earth.

About constellations and star charts.

And now remember - you rotated, and the furnishings in the room did not change their relative position.

In the same way, the stars retain their relative positions during the daily rotation of the sky, forming characteristic patterns. Such drawings are colloquially called constellations.

For example, in the upper right part of the photo, the constellation Orion is visible near the horizon.

The violent fantasy of people saw a group of bright stars from the constellation Orion of man. In Greek mythology, Orion was a famous hunter who could defeat any game.

In the past, the starry sky was depicted in the form of drawings with pictures, like the one that depicts Orion - the hunter and Taurus - the game.

Nowadays, they use maps of the starry sky, which differ from photographs or from drawings of the sky in that

The maps have coordinate lines, i.e. Objects are plotted on the map according to their celestial coordinates. Similarly, geographic maps also have coordinate lines (parallels and meridians), and objects are plotted on the map according to their coordinates - geographic latitude and longitude.

Celestial objects are depicted using symbols, so visually the view of the starry sky and the map are noticeably different (just like the view of some area from the window of an airplane is visually different from the map of the same area).

Stars are shown as black circles on the map. The larger the circle, the brighter the star.

A characteristic detail in the constellation of Orion is three stars located side by side on the same straight line.

If you look to the left along this straight line, you can see the brightest star in the sky - Sirius, otherwise it is called α (alpha) Canis Major, - Canis Major in Latin. Both in the figure and on the map, Sirius is depicted in the lower left corner.

The bold blue line is part of the celestial equator. The weaker blue lines parallel and perpendicular to the celestial equator are the coordinate lines.

The dotted lines are the boundaries of the constellations. A constellation is not a group of stars at all, as many people think.

A constellation is an area of ​​the sky within certain boundaries established by international agreement. There are 88 constellations in the sky. And that's it. - There is no more room in heaven!

And now remember: the microscopic man saw that the cat, which went about its business, moves in relation to the objects of the home environment.

Similarly, the Moon revolves around the Earth and therefore moves quite quickly across the sky relative to the stars. You can see for yourself. - A day later, the moon will be visible against the background of other stars.

And in general, all the celestial bodies of the solar system move across the sky, changing their position among the stars.