Our planet is in constant motion. Together with the Sun, it moves in space around the center of the Galaxy. And she, in turn, moves in the Universe. But the rotation of the Earth around the Sun and its own axis plays the greatest importance for all living things. Without this movement, conditions on the planet would be unsuitable for supporting life.
solar system
According to scientists, the Earth as a planet in the solar system was formed more than 4.5 billion years ago. During this time, the distance from the luminary practically did not change. The speed of the planet's movement and the gravitational force of the Sun balanced its orbit. It's not perfectly round, but it's stable. If the gravity of the star had been stronger or the speed of the Earth had noticeably decreased, then it would have fallen into the Sun. Otherwise, sooner or later it would fly into space, ceasing to be part of the system.
The distance from the Sun to the Earth makes it possible to maintain optimal temperature on its surface. The atmosphere also plays an important role in this. As the Earth rotates around the Sun, the seasons change. Nature has adapted to such cycles. But if our planet were at a greater distance, the temperature on it would become negative. If it were closer, all the water would evaporate, since the thermometer would exceed the boiling point.
The path of a planet around a star is called an orbit. The trajectory of this flight is not perfectly circular. It has an ellipse. The maximum difference is 5 million km. The closest point of the orbit to the Sun is at a distance of 147 km. It's called perihelion. Its land passes in January. In July, the planet is at its maximum distance from the star. The greatest distance is 152 million km. This point is called aphelion.
The rotation of the Earth around its axis and the Sun ensures a corresponding change in daily patterns and annual periods.
For humans, the movement of the planet around the center of the system is imperceptible. This is because the mass of the Earth is enormous. Nevertheless, every second we fly about 30 km in space. This seems unrealistic, but these are the calculations. On average, it is believed that the Earth is located at a distance of about 150 million km from the Sun. It makes one full revolution around the star in 365 days. The distance traveled per year is almost a billion kilometers.
The exact distance that our planet travels in a year, moving around the star, is 942 million km. Together with her we move through space in an elliptical orbit at a speed of 107,000 km/hour. The direction of rotation is from west to east, that is, counterclockwise.
The planet does not complete a full revolution in exactly 365 days, as is commonly believed. In this case, about six more hours pass. But for the convenience of chronology, this time is taken into account in total for 4 years. As a result, one additional day “accumulates”; it is added in February. This year is considered a leap year.
The speed of rotation of the Earth around the Sun is not constant. It has deviations from the average value. This is due to the elliptical orbit. The difference between the values is most pronounced at the perihelion and aphelion points and is 1 km/sec. These changes are invisible, since we and all the objects around us move in the same coordinate system.
Change of seasons
The Earth's rotation around the Sun and the tilt of the planet's axis make the seasons possible. This is less noticeable at the equator. But closer to the poles, the annual cyclicity is more pronounced. The northern and southern hemispheres of the planet are heated unevenly by the energy of the Sun.
Moving around the star, they pass four conventional orbital points. At the same time, alternately twice during the six-month cycle they find themselves further or closer to it (in December and June - the days of the solstices). Accordingly, in a place where the surface of the planet warms up better, the ambient temperature there is higher. The period in such a territory is usually called summer. In the other hemisphere it is noticeably colder at this time - it is winter there.
After three months of such movement with a periodicity of six months, the planetary axis is positioned in such a way that both hemispheres are in the same conditions for heating. At this time (in March and September - the days of the equinox) the temperature regimes are approximately equal. Then, depending on the hemisphere, autumn and spring begin.
Earth's axis
Our planet is a rotating ball. Its movement is carried out around a conventional axis and occurs according to the principle of a top. By resting its base on the plane in an untwisted state, it will maintain balance. When the rotation speed weakens, the top falls.
The earth has no support. The planet is affected by the gravitational forces of the Sun, Moon and other objects of the system and the Universe. Nevertheless, it maintains a constant position in space. The speed of its rotation, obtained during the formation of the core, is sufficient to maintain relative equilibrium.
The earth's axis does not pass perpendicularly through the globe of the planet. It is inclined at an angle of 66°33´. The rotation of the Earth around its axis and the Sun makes possible the change of seasons. The planet would “tumble” in space if it did not have a strict orientation. There would be no talk of any constancy of environmental conditions and life processes on its surface.
Axial rotation of the Earth
The rotation of the Earth around the Sun (one revolution) occurs throughout the year. During the day it alternates between day and night. If you look at the Earth's North Pole from space, you can see how it rotates counterclockwise. It completes a full rotation in approximately 24 hours. This period is called a day.
The speed of rotation determines the speed of day and night. In one hour, the planet rotates approximately 15 degrees. The speed of rotation at different points on its surface is different. This is due to the fact that it has a spherical shape. At the equator, the linear speed is 1669 km/h, or 464 m/sec. Closer to the poles this figure decreases. At the thirtieth latitude, the linear speed will already be 1445 km/h (400 m/sec).
Due to its axial rotation, the planet has a somewhat compressed shape at the poles. This movement also “forces” moving objects (including air and water flows) to deviate from their original direction (Coriolis force). Another important consequence of this rotation is the ebb and flow of tides.
the change of night and day
A spherical object is only half illuminated by a single light source at a certain moment. In relation to our planet, in one part of it there will be daylight at this moment. The unlit part will be hidden from the Sun - it is night there. Axial rotation makes it possible to alternate these periods.
In addition to the light regime, the conditions for heating the surface of the planet with the energy of the luminary change. This cyclicality is important. The speed of change of light and thermal regimes is carried out relatively quickly. In 24 hours, the surface does not have time to either heat up excessively or cool down below the optimal level.
The rotation of the Earth around the Sun and its axis at a relatively constant speed is of decisive importance for the animal world. Without a constant orbit, the planet would not remain in the optimal heating zone. Without axial rotation, day and night would last for six months. Neither one nor the other would contribute to the origin and preservation of life.
Uneven rotation
Throughout its history, humanity has become accustomed to the fact that the change of day and night occurs constantly. This served as a kind of standard of time and a symbol of the uniformity of life processes. The period of rotation of the Earth around the Sun is influenced to a certain extent by the ellipse of the orbit and other planets in the system.
Another feature is the change in the length of the day. The Earth's axial rotation occurs unevenly. There are several main reasons. Seasonal variations associated with atmospheric dynamics and precipitation distribution are important. In addition, a tidal wave directed against the direction of the planet’s movement constantly slows it down. This figure is negligible (for 40 thousand years per 1 second). But over 1 billion years, under the influence of this, the length of the day increased by 7 hours (from 17 to 24).
The consequences of the Earth's rotation around the Sun and its axis are being studied. These studies are of great practical and scientific importance. They are used not only to accurately determine stellar coordinates, but also to identify patterns that can influence human life processes and natural phenomena in hydrometeorology and other areas.
The earth rotates around an inclined axis from west to east. Half of the globe is illuminated by the sun, it is day there at that time, the other half is in the shadow, there it is night. Due to the rotation of the Earth, the cycle of day and night occurs. The Earth makes one revolution around its axis in 24 hours - a day.
Due to rotation, moving currents (rivers, winds) are deflected in the northern hemisphere to the right, and in the southern hemisphere to the left.
Rotation of the Earth around the Sun
The Earth rotates around the sun in a circular orbit, completing a full revolution in 1 year. The earth's axis is not vertical, it is inclined at an angle of 66.5° to the orbit, this angle remains constant during the entire rotation. The main consequence of this rotation is the change of seasons.
Consider the rotation of the Earth around the Sun.
- December 22- winter solstice. The southern tropic is closest to the sun (the sun is at its zenith) at this moment - therefore, it is summer in the southern hemisphere, and winter in the northern hemisphere. Nights in the southern hemisphere are short; on December 22, in the southern polar circle, the day lasts 24 hours, night does not come. In the northern hemisphere, everything is the other way around; in the Arctic Circle, the night lasts 24 hours.
- 22nd of June- day of the summer solstice. The northern tropic is closest to the sun; it is summer in the northern hemisphere and winter in the southern hemisphere. In the southern polar circle, night lasts 24 hours, but in the northern circle there is no night at all.
- March 21, September 23- days of the spring and autumn equinoxes The equator is closest to the sun; day is equal to night in both hemispheres.
Since ancient times, people have been interested in why night gives way to day, winter in spring, and summer in autumn. Later, when answers to the first questions were found, scientists began to take a closer look at the Earth as an object, trying to find out at what speed the Earth rotates around the Sun and around its axis.
In contact with
Earth movement
All celestial bodies are in motion, the Earth is no exception. Moreover, it simultaneously undergoes axial movement and movement around the Sun.
To visualize the movement of the Earth, just look at the top, which simultaneously rotates around an axis and quickly moves along the floor. If this movement did not exist, the Earth would not be suitable for life. Thus, our planet, without rotation around its axis, would be constantly turned to the Sun with one side, on which the air temperature would reach +100 degrees, and all the water available in this area would turn into steam. On the other side, the temperature would be constantly below zero and the entire surface of this part would be covered with ice.
Rotation orbit
Rotation around the Sun follows a certain trajectory - an orbit that is established due to the attraction of the Sun and the speed of movement of our planet. If the gravity were several times stronger or the speed was much lower, then the Earth would fall into the Sun. What if the attraction disappeared or greatly decreased, then the planet, driven by its centrifugal force, flew tangentially into space. This would be similar to spinning an object tied to a rope above your head and then suddenly releasing it.
The Earth's trajectory is shaped like an ellipse rather than a perfect circle, and the distance to the star varies throughout the year. In January, the planet approaches the point closest to the star - it is called perihelion - and is 147 million km away from the star. And in July, the Earth moves 152 million km away from the sun, approaching a point called aphelion. The average distance is taken to be 150 million km.
The Earth moves in its orbit from west to east, which corresponds to the “counterclockwise” direction.
It takes the Earth 365 days 5 hours 48 minutes 46 seconds (1 astronomical year) to complete one revolution around the center of the Solar System. But for convenience, a calendar year is usually counted as 365 days, and the remaining time is “accumulated” and adds one day to each leap year.
The orbital distance is 942 million km. Based on calculations, the speed of the Earth is 30 km per second or 107,000 km/h. For people it remains invisible, since all people and objects move the same way in the coordinate system. And yet it is very big. For example, the highest speed of a racing car is 300 km/h, which is 365 times slower than the speed of the Earth rushing along its orbit.
However, the value of 30 km/s is not constant due to the fact that the orbit is an ellipse. The speed of our planet fluctuates somewhat throughout the journey. The greatest difference is achieved when passing the perihelion and aphelion points and is 1 km/s. That is, the accepted speed of 30 km/s is average.
Axial rotation
The earth's axis is a conventional line that can be drawn from the north to the south pole. It passes at an angle of 66°33 relative to the plane of our planet. One revolution occurs in 23 hours 56 minutes and 4 seconds, this time is designated by the sidereal day.
The main result of axial rotation is the change of day and night on the planet. In addition, due to this movement:
- The earth has a shape with oblate poles;
- bodies (river flows, wind) moving in a horizontal plane shift slightly (in the Southern Hemisphere - to the left, in the Northern Hemisphere - to the right).
The speed of axial movement in different areas differs significantly. The highest at the equator is 465 m/s or 1674 km/h, it is called linear. This is the speed, for example, in the capital of Ecuador. In areas north or south of the equator, the rotation speed decreases. For example, in Moscow it is almost 2 times lower. These speeds are called angular, their indicator becomes smaller as they approach the poles. At the poles themselves, the speed is zero, that is, the poles are the only parts of the planet that are without movement relative to the axis.
It is the location of the axis at a certain angle that determines the change of seasons. Being in this position, different areas of the planet receive unequal amounts of heat at different times. If our planet was located strictly vertically relative to the Sun, then there would be no seasons at all, since the northern latitudes illuminated by the luminary during the daytime received the same amount of heat and light as the southern latitudes.
The following factors influence axial rotation:
- seasonal changes (precipitation, atmospheric movement);
- tidal waves against the direction of axial movement.
These factors slow down the planet, as a result of which its speed decreases. The rate of this decrease is very small, only 1 second in 40,000 years; however, over 1 billion years, the day has lengthened from 17 to 24 hours.
The movement of the Earth continues to be studied to this day.. This data helps to compile more accurate star maps, as well as determine the connection of this movement with natural processes on our planet.
For billions of years, day after day, the Earth rotates around its axis. This makes sunrises and sunsets commonplace for life on our planet. The Earth has been doing this since it formed 4.6 billion years ago. And will continue to do this until it ceases to exist. This will probably happen when the Sun turns into a red giant and swallows our planet. But why Earth?
Why does the Earth rotate?
The Earth was formed from a disk of gas and dust that revolved around the newborn Sun. Thanks to this spatial disk, dust and rock particles fell together to form the Earth. As the Earth grew, space rocks continued to collide with the planet. And they had an effect on it that made our planet rotate. And since all the debris in the early Solar System orbited the Sun in roughly the same direction, the collisions that caused the Earth (and most other bodies in the Solar System) to spin spun it in that same direction.
Gas and dust disk
A reasonable question arises: why did the gas-dust disk itself rotate? The Sun and the Solar System were formed at the moment when a cloud of dust and gas began to become denser under the influence of its own weight. Most of the gas came together to become the Sun, and the remaining material created the planetary disk surrounding it. Before it took shape, gas molecules and dust particles moved within its boundaries evenly in all directions. But at some point, randomly, some molecules of gas and dust combined their energy in one direction. This established the direction of rotation of the disk. As the gas cloud began to compress, its rotation accelerated. The same process occurs when skaters begin to spin faster if they press their arms closer to their body.
There are not many factors in space that can cause planets to rotate. Therefore, once they begin to rotate, this process does not stop. The rotating young solar system has high angular momentum. This characteristic describes the tendency of an object to continue spinning. It can be assumed that all exoplanets probably also begin to rotate in the same direction around their stars when their planetary system is formed.
And we are spinning in reverse!
It is interesting that in the solar system some planets have a direction of rotation opposite to their movement around the Sun. Venus rotates in the opposite direction relative to the Earth. And the axis of rotation of Uranus is tilted by 90 degrees. Scientists do not fully understand the processes that caused these planets to acquire such rotation directions. But they have some guesses. Venus may have received this rotation as a result of a collision with another cosmic body at an early stage of its formation. Or perhaps Venus began to rotate in the same way as the other planets. But over time, the Sun's gravity began to slow down its rotation due to its dense clouds. Which, combined with friction between the planet's core and its mantle, caused the planet to spin in the other direction.
In the case of Uranus, scientists suggested that the planet collided with a huge rocky debris. Or perhaps with several different objects that changed its axis of rotation.
Despite such anomalies, it is clear that all objects in space rotate in one direction or another.
Everything is spinning
Asteroids rotate. The stars are spinning. According to NASA, galaxies also rotate. It takes the solar system 230 million years to complete one revolution around the center of the Milky Way. Some of the fastest spinning objects in the Universe are dense, round objects called pulsars. They are the remnants of massive stars. Some city-sized pulsars can rotate around their axis hundreds of times per second. The fastest and most famous of them, discovered in 2006 and called Terzan 5ad, rotates 716 times per second.
Black holes can do this even faster. One of them, called GRS 1915+105, is believed to be capable of spinning between 920 and 1,150 times per second.
However, the laws of physics are inexorable. All rotations eventually slow down. When, it rotated around its axis at a rate of one revolution every four days. Today, our star takes about 25 days to complete one revolution. Scientists believe that the reason for this is that the Sun's magnetic field interacts with the solar wind. This is what slows down its rotation.
The Earth's rotation is also slowing down. The Moon's gravity affects the Earth in such a way that it slowly slows down its rotation. Scientists have calculated that the Earth's rotation has slowed down by a total of about 6 hours over the past 2,740 years. This amounts to just 1.78 milliseconds over the course of a century.
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When I was little I learned that The earth rotates. My grandfather once told me about sundials and what their principle is. It's so common to watch sunrise and sunset Sun, but what will happen if The earth will stop?
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 on 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 by thousandths of a second per year. Most of the planets in our system have the same direction of rotation, the only exceptions being 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 didn't notice whirlpool water in the bathroom. This phenomenon, despite its commonality, is quite a mystery for the scientific world. Indeed, in Northern Hemisphere the whirlpool is directed counterclock-wise, and in the opposite - everything is the other way around. Most scientists consider this a show 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 they blow counterclockwise, in the south - vice versa;
- the left rail of the railway wears out the most in Southern Hemisphere, whereas in the opposite - right;
- by the rivers in Northern Hemisphere pronounced right steep bank, in Yuzhny it’s the other way around.
What if she stops
It's interesting to imagine what would happen if our planet stops rotating. For an ordinary person, this would be equivalent to driving cars at 2000 km/h and then sudden braking. I think there is no need to explain the consequences of such an event, but this will not be the worst thing. If you are at this moment equator, the human body will continue to “fly” at a speed of almost 500 meters per second, but those who are lucky enough to be closer to poles, you will be able to survive, but not for long. The wind will become so strong that the force of its action will be comparable to the force nuclear bomb explosion, and wind friction will cause fires all over the planet.
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