The Earth, like other planets, revolves around the Sun. This path of the Earth is called the orbit (lat. Orbita - track, road). Evidence of the orbital motion of the Earth are the phenomena of aberration of the light of stars and their parallactic displacement, which are inherent in a periodic character. The periodicity is equal to one year, which corresponds to the time of revolution of the Earth around the Sun.
The movement of the Sun along the ecliptic is a reflection of the movement of the Earth in its orbit. The ecliptic is a large circle of the celestial sphere, formed when its orbital plane intersects it. The plane of the ecliptic is inclined to the plane of the celestial equator and intersects with it at an angle of 23°27". vice versa.
Earth orbit- an ellipse close to a circle, in one of the focuses of which is the Sun. The distance from the Earth to the Sun varies throughout the year from 147 million km at perihelion (January 2) to 152 million km at aphelion (July 5). The length of the orbit is over 930 million km. The Earth (more precisely, the barycenter) moves along its orbit from west to east, coinciding with the direction of its axial rotation, with an average speed of about 29.8 km/s and travels all the way in 365 days. 6 h 9 min 9 s. This period of time is called a stellar (sidereal) year.
tropical year- the time interval between two successive passages of the Sun through the vernal equinox. It is 20 minutes shorter than the sidereal year and is equal to 365 days. 5 h 48 min 46 s, since the vernal equinox slowly shifts in the direction of the Earth's orbital motion (towards the apparent annual motion of the Sun) at an angle of 50 "per year and the equinox occurs before the Sun passes 360 ° along the ecliptic. This phenomenon was called precession of the equinoxes, and it is caused by precession. Precession- slow cone-shaped rotation of the earth's axis around a perpendicular to the plane of the orbit with a vertex at the center of the earth. The period of its complete rotation is about 26 thousand years. The precession is caused by the attraction of the Earth's equatorial bulge by the Sun and Moon and their tendency to turn the earth's axis into a perpendicular position to the plane of the orbit in order to align the planes of the celestial equator and the ecliptic. But the Earth, like any rotating body, counteracts these forces, which causes a cone-shaped rotation of its axis around the poles (like the axis of a rotating top). Due to the change in the position of the earth's axis and the axis of the world, the position in space of the earth's and celestial equator and, accordingly, the points of the spring and autumn equinoxes change.
Due to the prelude of the equinoxes, the beginning of all seasons of the year is gradually shifted to earlier dates. After 13 thousand years, the dates of the spring and autumn equinoxes will change places, the summer of the northern hemisphere will fall on December, January and February, and the winter will fall on June, July and August.
The consequence of precession is also the movement of the poles of the world among the stars. If now the nearby star to the North Pole of the World (P) is the Polar Star in the constellation Ursa Minor, then in 13 thousand years, the polar star Vega in the constellation Lyra will be in its place and become.
In the modern era, the axis of rotation of the Earth is inclined to the plane of the orbit at an angle of 66.5 ° and moves during the year in space parallel to itself. This leads to the change of seasons and the inequality of day and night - the most important consequences of the revolution of the Earth in its orbit around the Sun.
If the earth's axis were perpendicular to the plane of the orbit, then the light-separating plane and Terminator(a light-dividing line on the surface of the Earth) would pass through both poles and would divide all the parallels in half, the day would always be equal to the night, and the sun's rays at the equator at noon would always fall vertically. As you move away from the equator, the angle of their incidence would decrease and at the poles would become equal to zero. Under these conditions, the heating of the earth's surface during the year would decrease from the equator to the poles and there would be no change of seasons.
The inclination of the earth's axis to the plane of the orbit and the preservation of its orientation in space cause a different angle of incidence of the sun's rays and, accordingly, differences in the flow of heat to the earth's surface in different seasons of the year, as well as unequal lengths of day and night throughout the year at all latitudes, except for the equator, where day and night are always equal to 12 hours.
22nd of June the earth's axis with its northern end is facing the sun. On this day - summer solstice- the sun's rays at noon fall vertically on the parallel of 23.5 ° N. sh. - this is the Northern Tropic (Greek tropikas - turning circle). All parallels north of the equator up to 66.5°N. sh. most of the day is illuminated - at these latitudes, the day is longer than the night. North of 66.5° N. sh. on the day of the summer solstice, the territory is completely illuminated by the Sun - there is a polar day. Parallel 66.5° N sh. is the boundary from which the polar day begins - this is the Arctic Circle. On the same day, at all parallels south of the equator to 66.5 ° S. sh. day is shorter than night. South of 66.5°S sh. the territory is not illuminated at all - there is a polar night. Parallel 66.5°S sh. - South polar circle. June 22 - the beginning of astronomical summer in the northern hemisphere and astronomical winter in the southern hemisphere.
December 22 the earth's axis with its southern end is facing the sun. On this day - winter solstice- the sun's rays at noon fall vertically on the parallel 23.5 ° S. sh. - Southern Tropic. On all parallels south of the equator up to 66.5 ° S. sh. the day is longer than the night. Starting from the Antarctic Circle, the polar day is established. On this day, on all parallels north of the equator up to 66.5 ° N. sh. day is shorter than night. Beyond the Arctic Circle is the polar night. December 22 - the beginning of astronomical summer in the southern hemisphere and astronomical winter in the northern hemisphere.
21 March- V day of spring equinox- And 23 September- V autumnal equinox- the terminator passes through both poles of the Earth and divides all the parallels in half. The northern and southern hemispheres are equally illuminated these days, day everywhere on Earth is equal to night. The sun is at its zenith above the equator at noon. On Earth, March 21 and September 23 are the beginning of astronomical spring and astronomical autumn in the respective hemispheres.
Seasonal rhythm in nature is associated with the change of seasons. It manifests itself in changes in temperature, air humidity and other meteorological indicators, in the regime of water bodies, in the life of plants, animals, etc.
Literature.
- Lyubushkina S.G. General geography: Proc. allowance for university students enrolled in special. "Geography" / S.G. Lyubushkina, K.V. pashkang, A.V. Chernov; Ed. A.V. Chernov. - M. : Education, 2004. - 288 p.
The mysterious and magical world of astronomy has attracted the attention of mankind since ancient times. People raised their heads up to the starry sky and asked eternal questions about why the stars change their position, why day and night come, why somewhere a blizzard howls, and somewhere in the desert plus 50 ...
The movement of the luminaries and calendars
Most of the planets in the solar system revolve around themselves. At the same time, they all make revolutions around the Sun. Some do it quickly and swiftly, others slowly and solemnly. Planet Earth is no exception, it is constantly moving in outer space. Even in ancient times, people, knowing the causes and mechanism of this movement, noticed a certain general pattern and began to draw up calendars. Even then, mankind was interested in the question of what is the speed of the Earth's revolution around the Sun.
The sun rises at sunrise
The movement of the Earth around its axis is the Earth's day. And the full passage of our planet in an ellipsoidal orbit around the star is a calendar year.
If you stand on the North Pole and draw an imaginary axis through the Earth to the South Pole, it turns out that our planet moves from west to east. Remember, even in the "Word of Igor's Campaign" it is said that "The sun rises at sunrise"? The east always meets the sun's rays before the west. That is why the new year in the Far East comes earlier than in Moscow.
At the same time, scientists determined that only two points on our planet are in a static position relative to the North and South Poles.
crazy speed
All other places on the planet are in perpetual motion. What is the speed of the Earth's revolution around the Sun? At the equator, it is the highest and reaches 1670 km per hour. Closer to the middle latitudes, for example, in Italy, the speed is already much lower - 1200 km per hour. And the closer to the poles, the smaller and smaller it is.
Equals 24 hours. That's what scientists say. We call it easier - a day.
How fast does the earth revolve around the sun?
350 times faster than a racing car
In addition to rotating around its axis, the Earth also makes an ellipsoidal movement around a star called the Sun. How fast does the earth revolve around the sun? Scientists have long calculated this indicator using complex formulas and calculations. The speed of the Earth around the Sun is 107 thousand kilometers per hour.
It's hard to even imagine these crazy, unrealistic numbers. For example, even the most racing car - 300 kilometers per hour - is 356 times less than the speed of the Earth in orbit.
It seems to us that this Sun rises and rises, that the Earth is motionless, and the luminary makes a circle in the sky. For a very long time, humanity thought just that, until scientists proved that everything happens the other way around. Today, even a schoolboy knows what is happening in the world: the planets smoothly and solemnly move around the Sun, and not vice versa. The Earth revolves around the Sun, and not at all in the way that ancient people previously believed.
So, we found out that the speed of rotation of the earth around its axis and the Sun are respectively 1670 km per hour (at the equator) and 107 thousand kilometers per hour, respectively. Wow, we're flying!
solar and sidereal year
A full circle, or rather, an elliptical oval, the planet Earth goes around the Sun in 356 days 5 hours 48 minutes 46 seconds. Astronomers call these numbers the "astrological year". Therefore, to the question "What is the frequency of the Earth's revolution around the Sun?" we answer simply and concisely: "Year". This indicator remains unchanged, but for some reason, every four years we have a leap year in which there is one more day.
It's just that astronomers have long agreed that the extra 5 and a half hours are not counted every year, but have chosen the number of the astronomical year, a multiple of days. Thus, the year is 365 days. But so that over time there is no failure, so that natural rhythms do not shift in time, every four years a single extra day appears in the calendar in February. These quarter days for 4 years are "gathered" into a full day - and we celebrate a leap year. Thus, answering the question of what is the frequency of the Earth's revolution around the Sun, feel free to say that one year.
In the scientific world, there are concepts of "solar year" and "stellar (sidereal) year". The difference between them is about 20 minutes and it occurs due to the fact that our planet orbits faster than the Sun returns to the place that astronomers have identified as the vernal equinox. We already know the speed of the Earth's revolution around the Sun, and the total period of the Earth's revolution around the Sun is 1 year.
Days and years on other planets
The nine planets of the solar system have their own "concepts" about speed, about what a day is and what an astronomical year is.
The planet Venus, for example, revolves around itself for 243 Earth days. Can you imagine how much you can do there in one day? And how long is the night!
But on Jupiter, the opposite is true. This planet spins around its axis at a gigantic speed and manages to complete a 360-degree rotation in 9.92 hours.
The speed of the passage of the Earth in orbit around the Sun is a year (365 days), but Mercury is only 58.6 Earth days. On Mars, the planet closest to Earth, a day lasts almost as long as on Earth - 24 and a half hours, but a year is almost twice as long - 687 days.
The revolution of the Earth around the Sun is 365 days. Now let's multiply this figure by 247.7 and get one year on the planet Pluto. We have a millennium, and on the most distant planet in the solar system - only four years.
Here are such paradoxical values and figures frightening in their scale.
Mysterious ellipse
To understand why the seasons periodically change on planet Earth, why it is hot in summer and cold in winter in our middle lane, it is important not only to answer the question of how fast the Earth rotates around the Sun, and in what way. You also need to understand how she does it.
And she does this not in a circle, but in an ellipse. If we draw around the Sun, we will see that it is closest to the luminary in January, and farthest - in July. The closest point of the Earth's position in orbit is called perihelion, and the farthest point is called aphelion.
Since the earth's axis is not in a strictly vertical position, but is deviated by about 23.4 degrees, and with respect to the ellipsoidal orbit, the angle of inclination increases to 66.3 degrees, it turns out that in different positions the Earth exposes different sides to the Sun.
Due to the tilt of the orbit, the Earth turns to the star in different hemispheres, hence the change in weather. When winter rages in the Northern Hemisphere, hot summers bloom in the Southern Hemisphere. Six months will pass - and the situation will change exactly the opposite.
Spin, earthly luminary!
Does the sun revolve around something? Of course! There are no absolutely motionless objects in space. All the planets, all their satellites, all comets and asteroids spin like clockwork. Of course, different celestial bodies have different speeds of rotation, and the angle of inclination of the axis, but still they are always in motion. And the Sun, which is a star, is no exception.
The solar system is not an independent closed space. It enters a huge one called the Milky Way. It, in turn, includes as many as 200 billion more stars. The sun moves in a circle around the center of this galaxy. The speed of rotation of the Sun around its axis and the Milky Way galaxy, scientists also calculated using long-term observations and mathematical formulas.
Today there is such data. The Sun completes its full cycle of circular motion around the Milky Way in 226 million years. In astronomical science, this figure is called the "galactic year". Moreover, if we imagine the surface of the galaxy as flat, then our luminary makes small fluctuations up and down, ending up alternately in the Northern and Southern hemispheres of the Milky Way. The frequency of such fluctuations is 30-35 million years.
Scientists believe that the Sun during the existence of the Galaxy managed to make 30 complete revolutions around the Milky Way. Thus, the Sun has lived only 30 galactic years so far. At least that's what scientists say.
Most scientists believe that life on Earth began 252 million years ago. Thus, it can be argued that the first living organisms on Earth appeared when the Sun made its 29th revolution around the Milky Way, that is, in the 29th year of its galactic life.
Body and gases move at different speeds
We learned a lot of interesting facts. We already know the rate of rotation of the Earth around the Sun, we found out what the astronomical and galactic year is, how fast the Earth and the Sun move in their orbits, and now we will determine how fast the Sun rotates around the axis.
The fact that the Sun rotates was noticed by ancient researchers. Similar spots periodically appeared on it, then disappeared, which made it possible to conclude that it rotates around its axis. But at what speed? Scientists, having the most modern methods of research, argued about this for a very long time.
After all, our luminary has a very complex composition. His body is solid. Inside is a solid core, around which is located a hot liquid mantle. Above it is a hard bark. In addition to all this, the surface of the Sun is shrouded in hot gas, which is constantly burning. It is a heavy gas that consists mainly of hydrogen.
So, the body of the Sun itself rotates slowly, and this burning gas - quickly.
25 days and 22 years
The outer shell of the Sun makes a complete rotation around its axis in 27 and a half days. Astronomers have been able to determine this by observing sunspots. But this is an average. For example, sunspots at the equator rotate faster and rotate around their axis in 25 days. At the poles, sunspots move at a rate of 31 to 36 days.
The body of the star itself rotates around its axis in 22.14 years. In general, in a hundred years of earthly life, the Sun will turn around its axis only four and a half times.
Why do scientists study the speed of rotation of our star so accurately?
Because it gives answers to many questions of evolution. After all, the star Sun is the source of life for all life on Earth. It is because of the flares on the Sun, according to many researchers, life appeared on Earth (252 million years ago). And it was because of the behavior of the Sun that dinosaurs and other reptiles died in ancient times.
Shine brightly on us, Sun!
People are constantly wondering if the Sun will exhaust its energy, will it go out? Of course, it will go out - there is nothing eternal in the world. And for such massive stars there is a time of birth, activity and decay. But so far the Sun is in the middle of the evolutionary cycle and it has enough energy. By the way, at the very beginning this star was less bright. Astronomers have determined that in the earliest stages of development, the brightness of the Sun was 70 percent lower than it is now.
The place where the sun goes down
Sunrise and sunset is a truly majestic picture. In all its beauty, it unfolds in open space - outside the city, in the field and especially on the sea. The part of the horizon where the sun rises and sets turns crimson…
This amazing planet got its name in honor of the god revered by the Romans, who patronizes trade. The god Mercury was swift. The name of the planet was not chosen by chance, because it moves faster than other planets across the sky. Mercury belongs ...
The Earth revolves around the Sun at an average speed of 29.76 km/sec. It travels all the way in orbit in 365 days 6 hours 9 minutes 9.6 seconds.
The most important consequence of the revolution of the Earth around the Sun with an almost unchanged position of its axis in space is the change of seasons.
The beginning of astronomical summer in the northern hemisphere - June 22 - summer solstice. In the southern hemisphere, astronomical winter begins at this time. On the summer solstice, the Earth is at aphelion. The axis of the Earth is inclined with its northern end to the Sun, and at noon the sun's rays fall vertically at a latitude of 23 ° 27 "N - on the northern tropic, on June 22, the Sun occupies the highest position in the year in the sky of all latitudes of the northern hemisphere. Latitudes north of 66 °33" s. sh. (from the Arctic Circle) are completely on the illuminated half of the Earth (Fig. 14, a), and the Sun does not set beyond the horizon here.
At all latitudes between the Arctic Circle and the Equator, the day is longer than the night. The illumination of the northern hemisphere on the day of the summer solstice is the greatest of the year. In the southern hemisphere on the day of the summer solstice, the Sun is especially low above the horizon. To the south of 66 ° 33 "S (from the southern polar circle) the polar night reigns, corresponding in duration to the polar day of the same latitudes of the northern hemisphere. At all latitudes between the southern polar circle and the equator, the day is shorter than the night. Illumination of the southern hemisphere per day summer solstice is the smallest of the year.
Continuously moving in orbit, on September 23, the Earth takes a position in which the light-separating line passes through the geographical poles, and day is equal to night on the whole Earth. This autumnal equinox. Both hemispheres (northern and southern) are equally illuminated on this day. September 23 - the beginning of astronomical autumn in the northern hemisphere and the beginning of astronomical spring - in the southern.
December 22, at winter solstice The Earth is at perihelion. The southern hemisphere faces the Sun, and astronomical summer begins there, while astronomical winter sets in in the northern hemisphere. The sun's rays at noon fall sheer on the southern tropic (23°27" S). The area near the south pole, bounded by the southern polar circle (66°33" S), is illuminated by the non-setting Sun; over the corresponding area in the northern hemisphere, the Sun does not rise. The illumination of the southern hemisphere is the greatest in the year, the northern hemisphere is the smallest. Like June 22, day equals night only at the equator.
On March 21, on the day of the vernal equinox, the Sun illuminates the Earth in the same way as on September 23: it stands at its zenith above the equator, and at all latitudes day is equal to night. In the northern hemisphere comes astronomical spring, in the southern - autumn.
The earth moves in orbit at different speeds. During the period when it is closest to the Sun (at perihelion), its speed is greatest. The lowest speed is during the passage of the Earth through aphelion. It follows that of all the seasons in the northern hemisphere, the longest is summer, and the shortest is winter, in the southern hemisphere it is vice versa. The differences in the length of the seasons are small. At present, spring in the northern hemisphere lasts 92.8 days, summer - 93.6, autumn - 89.8, winter - 89.0.
The fifth largest planet in the solar system - the Earth, formed 4.54 billion years ago from protoplanetary dust and gas, has the shape of a not quite regular ball and rotates not only around the Sun in an orbit in the form of a weakly expressed ellipse with an average speed of approximately 100 thousand km / hour, but also around its own axis. The rotation occurs when viewed from the North Pole, in the direction from west to east, or in other words counterclockwise. Precisely because the Earth revolves around the Sun and at the same time around its own axis, absolutely in all parts of this planet there is a periodic change of day and night, as well as a sequential change of the four seasons.
The average distance from the Sun to the Earth is approximately 150 million km, and the difference between the smallest and largest distance is approximately 4.8 million km, while the Earth's orbit changes its eccentricity very slightly, and the cycle is 94 thousand years. An important factor affecting the Earth's climate is the distance between it and the Sun. There are suggestions that the ice age on Earth began precisely at the time when it was at the maximum possible distance from the Sun.
Extra day on the calendar
The Earth makes one revolution around its own axis in about 23 hours and 56 minutes, and one revolution around the Sun takes 365 days and 6 hours. This period difference gradually accumulates and once every 4 years an extra day appears in our calendar (February 29), and such a year is called a leap year. Also, this process is influenced by the Moon located in the immediate vicinity, under the influence of the gravitational field of which the rotation of the Earth gradually slows down, and this, in turn, lengthens the day by about one thousandth every 100 years.
Significant climate change is coming
The change of seasons occurs due to the inclination of the Earth's axis of rotation to the orbit of the Sun. This angle is now 66° 33'. The attraction of other satellites and planets does not change the angle of inclination of the earth's axis, but makes the earth move in a circular cone - this process is called precession. At the moment, the position of the Earth's axis is such that the North Pole is opposite the North Star. Over the next 12 thousand years, the earth's axis will shift due to the impact of precession, and will be opposite the star Vega, which is only half the way (the full cycle of precession is 25,800 years), and will cause very significant climatic changes on absolutely the entire surface of the Earth.
Fluctuations Causing Earth's Climate Change
Twice a month at the moment of passing over the equator and twice a year when the Sun is in the same position, the attraction of the precession decreases and becomes equal to zero, after which it increases again, i.e., the rates of precession are oscillatory. These fluctuations are called nutation, they reach their maximum value on average once every 18.6 years and, in terms of their influence on climate, take second place after the change of seasons.
Briefly in the rotation of the Earth around the Sun.
Our planet is in constant motion. Together with the Sun, it moves in space around the center of the Galaxy. And that, in turn, moves in the universe. But the most important thing for all living things is the rotation of the Earth around the Sun and its own axis. Without this movement, the conditions on the planet would be unsuitable for sustaining life.
solar system
Earth as a planet of the solar system, according to scientists, was formed more than 4.5 billion years ago. During this time, the distance from the sun practically did not change. The speed of the planet and the gravitational pull of the sun balance its orbit. It is not perfectly round, but stable. If the force of attraction of the star were stronger or the speed of the Earth decreased noticeably, then it would fall on 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 the optimum 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 further away, then 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 round. 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 provides, respectively, a change in daily regimes and annual periods.
For a person, 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 through space about 30 km. It seems unrealistic, but such 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 complete revolution around the star in 365 days. The distance traveled in a year is almost a billion kilometers.
The exact distance that our planet travels in a year, moving around the sun, is 942 million km. Together with her, we move in space in an elliptical orbit at a speed of 107,000 km / h. The direction of rotation is from west to east, that is, counterclockwise.
The planet does not complete a complete revolution in exactly 365 days, as is commonly believed. It still takes about six hours. But for the convenience of chronology, this time is taken into account in total for 4 years. As a result, one additional day “runs in”, it is added in February. Such a year is considered a leap year.
The speed of rotation of the Earth around the Sun is not constant. It has deviations from the mean. This is due to the elliptical orbit. The difference between the values is most pronounced at the points of perihelion and aphelion and is 1 km/sec. These changes are imperceptible, since we and all the objects around us move in the same coordinate system.
change of seasons
The rotation of the Earth around the Sun and the tilt of the planet's axis make it possible for the seasons to change. It 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 by the energy of the Sun unevenly.
Moving around the star, they pass four conditional points of the orbit. At the same time, twice in turn during the semi-annual cycle, they turn out to be 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 is higher there. The period in such a territory is usually called summer. In the other hemisphere at this time it is noticeably colder - it is winter there.
After three months of such movement, with a frequency of six months, the planetary axis is located 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 come.
earth axis
Our planet is a spinning ball. Its movement is carried out around a conditional axis and occurs according to the principle of a top. Leaning with the base in the plane in the untwisted state, it will maintain balance. When the speed of rotation weakens, the top falls.
The earth has no stop. The forces of attraction of the Sun, the Moon and other objects of the system and the Universe act on the planet. Nevertheless, it maintains a constant position in space. The speed of its rotation, obtained during the formation of the nucleus, is sufficient to maintain relative equilibrium.
The earth's axis passes through the planet's ball is not perpendicular. It is inclined at an angle of 66°33´. The rotation of the Earth on its axis and the Sun makes it possible to change the seasons of the year. The planet would "tumble" in space if it did not have a strict orientation. There would be no question 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 during 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 about 24 hours. This period is called a day.
The speed of rotation determines the speed of the change 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 / s. Closer to the poles, this figure decreases. At the thirtieth latitude, the linear speed will already be 1445 km / h (400 m / s).
Due to axial rotation, the planet has a slightly compressed shape from the poles. Also, this movement "forces" moving objects (including air and water flows) to deviate from the original direction (Coriolis force). Another important consequence of this rotation is the ebbs and flows.
the change of night and day
A spherical object with the only light source at a certain moment is only half illuminated. In relation to our planet in one part of it at this moment there will be a day. The unlit part will be hidden from the Sun - there is night. Axial rotation makes it possible to change 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 cycle 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 overheat or cool below the optimum.
The rotation of the Earth around the Sun and its axis with a relatively constant speed is of decisive importance for the animal world. Without the constancy of the orbit, the planet would not have stayed in the zone of optimal heating. 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
Mankind 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 to a certain extent is influenced by the ellipse of the orbit and other planets of the system.
Another feature is the change in the length of the day. The axial rotation of the Earth is uneven. There are several main reasons. Seasonal fluctuations associated with the dynamics of the atmosphere and the distribution of precipitation are important. In addition, the tidal wave, directed against the motion of the planet, constantly slows it down. This figure is negligible (for 40 thousand years for 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 affect human life processes and natural phenomena in hydrometeorology and other fields.
