Why does the planet earth rotate. Why is the planet earth spinning

Hello dear readers! Today I would like to touch on the topic of the Earth and, and I thought that a post on how the Earth rotates will be useful to you 🙂 After all, day and night, and also the seasons, depend on it. Let's get to know everyone better.

Our planet rotates on its axis and around the sun. When it makes one revolution around its axis, one day passes, and when it circles the Sun, one year. More on this below:

Earth axis.

Earth's axis (axis of rotation of the Earth) - this is a straight line around which the daily rotation of the Earth occurs; this line passes through the center and intersects the surface of the Earth.

The tilt of the Earth's axis of rotation.

The axis of rotation of the Earth is inclined to the plane at an angle of 66°33´; thanks to this happens . When the Sun is over the Tropic of the North (23°27´ N), summer begins in the Northern Hemisphere, and the Earth is at its furthest distance from the Sun.

When the Sun rises over the Tropic of the South (23°27´ S), summer begins in the Southern Hemisphere.

In the Northern Hemisphere, winter begins at this time. The attraction of the Moon, the Sun and other planets does not change the angle of the earth's axis, but leads to the fact that it moves along a circular cone. This movement is called precession.

The North Pole is pointing towards the North Star. The earth's axis over the next 12,000 years, as a result of precession, will pass approximately halfway, and will be directed to the star Vega.

About 25,800 years constitutes a complete cycle of precession and significantly influences the climate cycle.

Twice a year, when the Sun is directly over the equator, and twice a month, when the Moon is in a similar position, the attraction due to precession decreases to zero and there is a periodic increase and decrease in the rate of precession.

Such oscillatory movements of the earth's axis are known as nutation, which peaks every 18.6 years. In terms of its impact on climate, this periodicity ranks second after change of seasons.

Rotation of the Earth around its axis.

Earth's daily rotation the movement of the Earth counterclockwise, or from west to east, as viewed from the North Pole of the world. The rotation of the Earth determines the length of the day and causes day and night to change.

The Earth makes one revolution around its axis in 23 hours 56 minutes and 4.09 seconds. During the period of one revolution around the Sun, the Earth makes approximately 365 ¼ revolutions, which is one year or 365 ¼ days.

Every four years, another day is added to the calendar, because for each such turn, except for a whole day, another quarter of a day is spent. The rotation of the Earth gradually slows down the gravitational pull of the Moon, and prolongs the day by about 1/1000 of every century.

Judging by the geological data, the rate of rotation of the Earth could change, but not more than 5%.

Around the Sun, the Earth rotates in an elliptical orbit, close to circular, at a speed of about 107,000 km / h in the direction from west to east. The average distance to the Sun is 149,598 thousand km, and the difference between the smallest and the largest distance is 4.8 million km.

The eccentricity (deviation from the circle) of the earth's orbit changes slightly over a cycle of 94 thousand years. It is believed that the formation of a complex climatic cycle is facilitated by changes in the distance to the Sun, and the advance and retreat of glaciers during ice ages are associated with its individual stages.

Everything in our vast universe is very complex and precise. And our Earth is just a point in it, but this is our home, which we learned a little more about from a post about how the Earth rotates. See you in new posts about the study of the Earth and the Universe🙂

As a child, I learned that The earth is spinning. My grandfather once told me about a sundial and what its principle is. It's so habitual to watch sunrise and sunset sun, but what happens if The earth will stop?

In which direction does the earth rotate

It all depends on how you look at it. Relatively South Pole, the globe will rotate in the direction clockwise, and quite the opposite for north pole. It is logical that the rotation occurs in the direction of the east - after all, the Sun appears from the east and disappears in the west. Scientists have found that the planet is gradually slows down thousandths of a second per year. Most of the planets in our system have the same direction of rotation, the only exceptions are Uranus And Venus. If you look at the Earth from space, you can notice two types of movement: around its axis, and around the star - the Sun.

Few people noticed whirlpool water in the bathroom. This phenomenon, despite its routine, is a rather big mystery for the scientific world. Indeed, in northern hemisphere whirlpool directed counterclock-wise, and vice versa. Most scientists consider it a manifestation of power Coriolis(inertia caused by rotation Earth). Some other manifestations of this force can be cited in favor of this theory:

• V northern hemisphere winds of the central part cyclone blow counterclockwise, in the south - vice versa;
• the left rail of the railway wears out the most in southern hemisphere, while in the opposite - right;

• by the rivers northern hemisphere pronounced right steep bank, in the South - on the contrary.

What if she stops

It is interesting to guess what will happen if our planet stop spinning. For an ordinary person, this would be equivalent to driving cars at a speed of 2000 km/h and then hard braking. I think it is not necessary to explain the consequences of such an event, but it will not be the worst. If you are at this moment equator, the human body will continue to “fly” at a speed of almost 500 meters per second, however, those who are lucky enough to be closer to poles will survive, but not for long. The wind will become so strong that in terms of the strength of its action it will be comparable to the force nuclear bomb explosion, and the friction of the winds will cause fires all over the world.

The theory of the world as a geocentric system was repeatedly criticized and questioned in the old days. It is known that Galileo Galilei worked on the proof of this theory. It is to him that the phrase that went down in history belongs: “And yet it spins!”. But still, it was not he who managed to prove this, as many people think, but Nicolaus Copernicus, who in 1543 wrote a treatise on the movement of celestial bodies around the Sun. Surprisingly, despite all this evidence, about the circular motion of the Earth around a huge star, there are still open questions in theory about the reasons that prompt it to this movement.

Reasons for the move

The Middle Ages are over, when people considered our planet to be motionless, and no one disputes its movements. But the reasons why the Earth is heading on a path around the Sun are not known for certain. Three theories have been put forward:

• inert rotation;
• magnetic fields;
• exposure to solar radiation.

There are others, but they do not stand up to scrutiny. It is also interesting that the question: “In which direction does the Earth rotate around a huge celestial body?” Is also not correct enough. The answer to it has been received, but it is accurate only with respect to the generally accepted guideline.

The sun is a huge star around which life is concentrated in our planetary system. All these planets move around the Sun in their orbits. The earth moves in the third orbit. Studying the question: “In which direction does the Earth rotate in its orbit?”, Scientists have made many discoveries. They realized that the orbit itself is not ideal, so our green planet is located from the Sun at different points at different distances from each other. Therefore, an average value was calculated: 149,600,000 km.

The Earth is closest to the Sun on January 3rd and farther away on July 4th. The following concepts are associated with these phenomena: the smallest and largest temporary day in the year, in relation to the night. Studying the same question: “In which direction does the Earth rotate in its solar orbit?”, Scientists made one more conclusion: the process of circular motion occurs both in orbit and around its own invisible rod (axis). Having made the discoveries of these two rotations, scientists asked questions not only about the causes of such phenomena, but also about the shape of the orbit, as well as the speed of rotation.

How did scientists determine in which direction the Earth rotates around the Sun in the planetary system?

The orbital picture of the planet Earth was described by a German astronomer and mathematician In his fundamental work New Astronomy, he calls the orbit elliptical.

All objects on the Earth's surface rotate with it, using conventional descriptions of the planetary picture of the solar system. It can be said that, observing from the north from space, to the question: “In which direction does the Earth rotate around the central luminary?”, The answer will be: “From west to east.”

Comparing with the movements of the hands in the clock - this is against its course. This point of view was accepted with regard to the North Star. The same will be seen by a person who is on the surface of the Earth from the side of the Northern Hemisphere. Having imagined himself on a ball moving around a fixed star, he will see his rotation from right to left. This is equivalent to going against the clock or from west to east.

earth axis

All this also applies to the answer to the question: “In which direction does the Earth rotate around its axis?” - in the opposite direction of the clock. But if you imagine yourself as an observer in the Southern Hemisphere, the picture will look different - on the contrary. But, realizing that in space there are no concepts of west and east, scientists pushed off from the earth's axis and the North Star, to which the axis is directed. This determined the generally accepted answer to the question: "In which direction does the Earth rotate around its axis and around the center of the solar system?". Accordingly, the Sun is shown in the morning from the horizon from the east, and is hidden from our eyes in the west. It is interesting that many people compare the earth's revolutions around its own invisible axial rod with the rotation of a top. But at the same time, the earth's axis is not visible and is somewhat tilted, and not vertical. All this is reflected in the shape of the globe and the elliptical orbit.

Sidereal and solar days

In addition to answering the question: “In which direction does the Earth rotate clockwise or counterclockwise?” Scientists calculated the time of revolution around its invisible axis. It is 24 hours. Interestingly, this is only an approximate number. In fact, a complete revolution is 4 minutes less (23 hours 56 minutes 4.1 seconds). This is the so-called star day. We consider a day on a solar day: 24 hours, since the Earth needs an additional 4 minutes every day in its planetary orbit to return to its place.

“And yet she turns!” - this famous phrase of the great Italian astronomer G. Galileo most likely belongs to the realm of legends (it is unlikely that the Holy Inquisition would have allowed him such a formal renunciation), but it has forever remained in the memory of mankind as a kind of monument of how much work it took to understand that ours rotates , and not only around the Sun, but also around its axis. But proving the rotation of the Earth was only the beginning, it was still necessary to explain why this happens!

To find an explanation for this, we will have to travel back to those distant times when the solar system in general and the Earth in particular were born from a huge gas and dust cloud. This cloud itself also rotated - without this, nothing would have happened, and it would have floated in space, remaining only a cloud and nothing more. But the rotation made it shrink, and the particles that make it up collided with each other and "clumped together." At first these were small particles, then large ones were formed from them, continuing to collide with each other, then the same thing happened with fairly large bodies - planetesimals ... but no matter how large the colliding bodies were, the impulses of their movement did not disappear! The new formation continued to rotate by inertia, having received an additional impulse from the collision of bodies merged with each other.

Collision with large objects could also affect the rotation of already "ready" (or almost "ready") planets. For example, Venus rotates differently than all other planets - in the opposite direction, and Uranus generally rotates, "lying on its side", i.e. its axis of rotation differs only slightly from the plane of the orbit. Scientists suggest that this is due to a collision with large objects that took place during the "youth" of the solar system, when there were an order of magnitude more planets, and many of them moved in emergency orbits (i.e., in such orbits that made collisions inevitable ). In this regard, we were “lucky”: the Earth also survived a collision with a very large planet, approximately the size of Mars (astronomers even gave it a name - Theia), but this did not affect its rotation, in any case, it did not affect how it happened with Venus or Uranus.

However, it would be wrong to say that the collision with Theia did not affect the rotation of the Earth at all. We received as a memory of this big collision our only natural satellite - the Moon, and now it really affects the rotation of the Earth! The fact is that one celestial body with its gravity is quite capable of slowing down the rotation of another, so the Moon slows down the rotation of the Earth. True, we are talking about fractions of a second per year - but after all, over centuries and millennia, fractions of seconds add up to seconds, seconds to minutes, and minutes to hours! The English astronomer R. Stephenson analyzed the astronomical observations of the sages of Babylon, Egypt and other civilizations of the Ancient World, starting from 700 BC. It turned out that if we were transported by a time machine to 700 BC. at the same time of day, we would have to set the clock back to 7 o'clock! An impressive deviation ... and in the days when dinosaurs lived, the day was 21 hours. Why, if there were no Moon, the Earth day would last only six hours!

However, the speed of rotation of the planets is affected not only by the gravity of other bodies, but also by the density of its matter. The closer the planet is to the Sun, the higher its density, which is why the small Mercury rotates around its axis much more slowly than the giant Jupiter.

Children ask a lot of questions that confuse even well-educated and literate parents. Why does the Sun shine, why is the sky blue, why does the Earth rotate on its axis? Why do planets rotate at all? The question is childish and naive. But not every adult can intelligibly answer. Revolve and all, so it should be. Not really. The process is longer, more interesting, more unexpected than many believe.

Why do the planets rotate around their axis - how did this happen?

It began at a time when the star of our nebula, the Sun, was "young". The solar system and planets did not exist - the system began to form from protomatter (protoplanetary cloud). The protomatter looks like a dusty disk, the cloud, together with other cold solid bodies, carried away the newly formed Sun from the galaxy.

Most of the protoplanetary cloud went to the formation of the Sun. The remaining around the space "garbage" moved chaotically. Periodically, solid particles collided, some collapsed and turned into dust, others combined and formed a cosmic body. It happened randomly and randomly.

Large bodies accumulated more and more mass due to the combination with dust and gas. Scientists call this process accretion. As the mass of the newly formed cosmic body increased, accretion proceeded more actively.

During this period, the body did not have a perfectly round or oval shape. It was like a lump of plasticine in the fingers of a child. It was difficult to call it a planet, they began to be called planetesimals - small planets. Due to their asymmetrical, angular shape, planetesimals are unstable. Under the influence of the solar wind, radiation and other bodies moving just as chaotically, the future Earth spun and moved back and forth like a broken top. She did not have a precisely established orbit, an axis of rotation.

But one day - after hundreds of millions of years of chaotic throwing - the Earth got out of its unstable rotation and began to slowly rotate around its own axis. Solar energy made the planet rotate faster, dust and small bodies continued to flow from the protoplanetary cloud. "Pushed" by the solar wind, collecting small particles, cosmic dust, gases, the Earth acquired an almost perfectly round shape, a constant axis and rotation speed.

After several thousand million years, the protomatter from the dusty disk ended - the planets of the solar system had already formed and acquired a round shape. But the rotation did not stop, the energy of the Sun was enough, as it is enough now to feed the rotation. Shapeless planetozimals floating around the Sun did not themselves rotate around the axis, they were “pushed” - and this happened a billion years ago.

That is why the planets rotate in - and the Earth, including.

The earth rotates around its own axis, and each of us, together with the planet, at a speed of 1500 km / h.

The axis of rotation of our planet is tilted by 66°34′ relative to the axis of its orbit - and we do not fall!

Rotation is carried out from west to east - in the opposite direction in comparison with the movement of the Sun and Moon in the sky.

This is one of the theories why the planets rotate on their own axis, but it seems to be viable and logical.

You can find more interesting and impressive facts about the planets and space in general on the website of the popular science online magazine