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The globe rotates around its axis. Earth movements

Like all the planets of our huge solar system The Earth makes two main revolutions - around its axis and around the Sun. The time it takes for one rotation of the Earth around its axis is called a day, and the period during which it circles its orbit around the Sun is called a year. This movement is the key to life and physical laws on the planet on which we all exist. At the slightest failure (which has not happened yet), the work of all spheres of the Earth, ecosystems and living organisms will be disrupted.

Features of the planet's rotation

Both in the people and in science, the time of one rotation of the Earth around its axis is called a day. They consist of day and night, which last on average 24 hours. Our planet rotates counterclockwise, that is, from west to east. It is thanks to this that residents of the eastern regions are the first to greet the dawn, and the inhabitants of the western hemisphere are the last. An axis is a conventional line that passes through the south and north poles of the planet. Thus, these extreme points do not participate in the rotation process, while all other parts of the earth move.

Since the planet moves from west to east, we can observe how the entire celestial sphere as if passing us in the opposite direction, that is, from east to west. This applies to both the Sun and all the stars that we have. The exception is the Moon, since it is an earthly satellite that has an individual orbit.

The movement of our planet in numbers

It is the daily period that determines the speed around the axis. In 24 hours, this celestial body must complete a complete revolution, taking into account its own parameters and mass. We have already said that the axis permeates the Earth from north to south, and during this process the poles do not rotate around it. At this time, all other zones, including the circumpolar and equatorial ones, move at a certain pace. The speed of rotation of the Earth near the equator is maximum. It reaches 1670 km/h. Moreover, in this area, day and night have an equal number of hours throughout the year.

The Earth's rotation speed in Italy reaches an average of 1200 km/h with a seasonal change in the length of day and night. Thus, the closer we move to the poles, the slower the planet rotates there, gradually coming to zero.

What types of days are there and how are they calculated?

The time of one rotation of the Earth around its axis is called a day, and exactly 24 hours are placed in this interval. But it is worth remembering that there are such concepts as solar days and sidereal days, which have a small but significant difference.

First, let's look at all the features of the first type. Firstly, not every day lasts exactly 24 hours. At those moments when the planet approaches the Sun, its speed of rotation around its axis increases. During periods of distance from the main body of the system, the movement of planet Earth slows down. Therefore, in summer the days may pass a little faster, and in winter they last longer.

As for the sidereal day, its duration is 23 hours, 56 minutes and 4 seconds. This is the time during which our planet rotates around its axis relative to some distant star. That is, if the distant luminary turned out to be the Sun, then the entire rotation, consisting of 360 degrees, would be complete during this period. Well, in order for it to reach the end relative to the Sun itself, it is necessary to go one more degree, which takes just four minutes.

The second important rotation of the planet is around the Sun

The Earth circles the Sun in an elliptical orbit. That is, its circulation occurs not in a clear circle shape, but in an oval pattern. The speed of the Earth around the Sun is on average 107,000 km/h, but this unit is not constant. The average distance of our planet from the sun is 150 million kilometers. An accurate and unchangeable unit is the degree of inclination of the earth's axis relative to the orbit - 66 degrees and 33 seconds, regardless of the time of day or year. It is this inclination, coupled with the shape of the orbit, the variable speed of movement and circulation, that gives us the opportunity to feel seasonal climate changes, but not in all latitudes. If daily fluctuations in time and any changes are multiplied by zero near the poles, then seasonal features also freeze at the equator. Every day from year to year here passes the same way as the previous one, with the same weather, as well as the length of day and night.

The ecliptic and its annual cycle

The term “ecliptic” means a section of the celestial sphere that is within the boundaries of the Moon. Within the boundaries of this conventional circle, all the main movements of our planet occur, as well as the revolution of the Moon around it. It is worth noting that the latter has a significant influence on the climate, the hydrosphere, and the Moon can be the cause of eclipses, lithospheric metamorphoses and much more.

As for the ecliptic itself, this plane has its own celestial equator, which has certain astronomical coordinates. The inclination of all planets in the solar system is calculated relative to them. The position of the stars and galaxies that we see in the sky is calculated in a similar way (after all, their light falls on the ecliptic, therefore, all those viewed are part of it). This theory is the basis of astrology. According to this science, those constellations that pass through the ecliptic make up the Zodiac. The only unit that does not fall into this category is Ophiuchus. This constellation is visible in the sky, but it is not in the astrological tables.

Summing up

We have determined that the time of one revolution of the Earth around its axis is called a day. The latter are solar (24 hours) or sidereal (23 hours 56 minutes). The change of day and night occurs in all latitudes of the planet with the exception of the poles. There the earth's rotation speed is zero. The planet's revolution around the Sun occurs every year - 365 days. During this period, there is a change of seasons in all corners of the Earth, but not at the equator. This zone is the most stable, while it rotates around its axis with

The Earth's orbit is the trajectory of its rotation around the Sun, its shape is an ellipse, it is located on average at a distance of 150 million kilometers from the Sun (the maximum distance is called aphelion - 152 million km, the minimum - perihelion, 147 million km).

The Earth completes a full revolution around the Sun, 940 million km long, moving from west to east at an average speed of 108,000 km/h in 365 days, 6 hours, 9 minutes and 9 seconds, or one sidereal year.

The movement of the planet in its orbit around the Sun and the angle of inclination of the axis of rotation to the plane where they move celestial bodies, directly affect the change of seasons and the inequality of day and night.

Features of the Earth's rotation around the Sun

(Structure of the Solar System)

In ancient times, astronomers believed that the Earth was located at the center of the Universe and all celestial bodies revolved around it; this theory was called geocentric. It was debunked by the Polish astronomer Nicolaus Copernicus in 1534, who created a heliocentric model of the world, which proved that the Sun cannot revolve around the Earth, no matter how much Ptolemy, Aristotle and their followers wanted it.

The Earth revolves around the Sun along an elliptical path called an orbit, its length is about 940 million km and the planet travels this distance in 365 days 6 hours 9 minutes and 9 seconds. After four years, these six hours accumulate per day, they are added to the year as another day (February 29), such a year is a leap year.

(Perihelion and aphelion)

During the period of movement along a given trajectory, the distance from the Earth to the Sun can be maximum (this phenomenon occurs on July 3 and is called aphelion or apohelion) - 152 million. km or minimum - 147 million. km (occurs on January 3, called perihelion), but this is not, as one might mistakenly assume, a consequence of the change of seasons.

Change of seasons

Due to the inclination of the earth's axis to the plane of its orbit around the Sun at 66.5º, the earth's surface receives an unequal amount of heat and light, which causes the change of seasons and changes in the duration of day and night.

Note:

  • The angle of inclination of the earth's axis from the ecliptic axis = 23.44º degrees ( tilt of the Earth's rotation axis)
  • The angle of inclination of the earth's axis to the plane of its orbit around the Sun = 66.56º degrees ( determines the climatic changes of the seasons throughout the year)

Equatorial days and nights are always equally long, they last 12 hours.

Speed ​​of the Earth moving in orbit

Earth's revolution around the Sun: 365 days 6 hours 9 minutes and 9 seconds

Average speed of the Earth in its orbit around the Sun: 30 km/s or 108,000 km/h (it's 1/10000th the speed of light)

For comparison, the diameter of our planet is 12,700 km, with this speed it is possible to cover this distance in 7 minutes, and the distance from the Earth to the Moon (384 thousand km) in four hours. Moving away from the Sun during the aphelion period, the Earth's speed slows down to 29.3 km/s, and during the perihelion period it accelerates to 30.3 km/s.

Spring and autumn equinoxes

  • March 20- spring equinox
  • September 22- autumnal equinox
  • June 21 summer solstice
  • December 22- winter solstice

The places where the plane of the celestial equator intersects the plane of the ecliptic are designated by the vernal points ( March 20) and autumnal equinox ( September 22), days and nights are equally long, and the areas of the hemispheres facing the Sun are evenly illuminated and warmed, the Sun's rays fall on the equator line at an angle of 90º. The astronomical beginning of spring and autumn in the corresponding hemispheres is calculated using the dates of the spring and autumn equinoxes.

There are also points of summer ( June 21) and winter ( December 22) solstice, the rays of the Sun become perpendicular not to the equator line, but to the Southern and Northern Tropics (the southern and northern parallels are 23.5º). On the day of the summer solstice, June 21, in the Northern Hemisphere, up to 66.5 parallels, the day is longer than the night, in Southern Hemisphere- the night is longer than the day, this date is the astronomical beginning of summer in northern latitudes and winter in southern latitudes.

On December 22 (winter solstice day) in the Southern Hemisphere up to the 66.5 parallel the day length is longer, in the Northern Hemisphere up to the same parallel it is shorter. The date of the winter solstice is the astronomical beginning of winter in the Northern Hemisphere and the beginning of summer in the Southern Hemisphere.

The Earth is constantly in motion, rotating around the Sun and around its own axis. This movement and the constant tilt of the Earth's axis (23.5°) determines many of the effects that we observe as normal phenomena: night and day (due to the rotation of the Earth on its axis), the change of seasons (due to the tilt of the Earth's axis), and different climate in different areas. Globes can be rotated and their axis is tilted like the Earth’s axis (23.5°), so with the help of a globe you can trace the movement of the Earth around its axis quite accurately, and with the help of the Earth-Sun system you can trace the movement of the Earth around the Sun.

Rotation of the Earth around its axis

The earth rotates on its own axis from west to east (counterclockwise when viewed from the side North Pole). It takes the Earth 23 hours, 56 minutes, and 4.09 seconds to complete one full revolution on its own axis. Day and night are caused by the rotation of the Earth. The angular velocity of the Earth's rotation around its axis, or the angle through which any point on the Earth's surface rotates, is the same. It is 15 degrees in one hour. But the linear speed of rotation anywhere at the equator is approximately 1,669 kilometers per hour (464 m/s), decreasing to zero at the poles. For example, the rotation speed at latitude 30° is 1445 km/h (400 m/s).
We do not notice the rotation of the Earth for the simple reason that in parallel and simultaneously with us all objects around us move at the same speed and there are no “relative” movements of objects around us. If, for example, a ship moves uniformly, without acceleration or braking, through the sea in calm weather without waves on the surface of the water, we will not feel at all how such a ship is moving if we are in a cabin without a porthole, since all objects inside the cabin will be move parallel with us and the ship.

Movement of the Earth around the Sun

While the Earth rotates on its own axis, it also rotates around the Sun from west to east counterclockwise when viewed from the north pole. It takes the Earth one sidereal year (about 365.2564 days) to complete one full revolution around the Sun. The path of the Earth around the Sun is called the Earth's orbit and this orbit is not perfectly round. The average distance from the Earth to the Sun is approximately 150 million kilometers, and this distance varies up to 5 million kilometers, forming a small oval orbit (ellipse). The point in the Earth's orbit closest to the Sun is called Perihelion. The earth passes this point in early January. The point of the Earth's orbit farthest from the Sun is called Aphelion. The earth passes this point in early July.
Since our Earth moves around the Sun along an elliptical path, the speed along the orbit changes. In July, the speed is minimal (29.27 km/sec) and after passing aphelion (upper red dot in the animation) it begins to accelerate, and in January the speed is maximum (30.27 km/sec) and begins to slow down after passing perihelion (lower red dot ).
While the Earth makes one revolution around the Sun, it covers a distance equal to 942 million kilometers in 365 days, 6 hours, 9 minutes and 9.5 seconds, that is, we rush along with the Earth around the Sun at an average speed of 30 km per second (or 107,460 km per hour), and at the same time the Earth rotates around its own axis once every 24 hours (365 times per year).
In fact, if we consider the movement of the Earth more scrupulously, it is much more complex, since the Earth is influenced by various factors: the rotation of the Moon around the Earth, the attraction of other planets and stars.

The Earth is constantly in motion, rotating around its own axis and around the Sun. This determines the origin of various phenomena on its surface: the change of seasons, the alternation of day and night. Favorable conditions for life on Earth are due to this movement and the favorable location of the planet relative to the Sun (approximately 150 million kilometers away). If the planet were closer, water would evaporate from its surface. If further, all living things would freeze. The atmosphere also plays an important role, protecting against harmful cosmic rays.

Let us dwell in more detail on two such constant invisible companions of life as the movement of the Earth around an imaginary line (axis) and the Sun.

The speed of rotation of the Earth around its axis

Earth is the third planet from the Sun. Along with all the others, it revolves around the Sun, and also has its own rotation around its axis. The giant planets are considered the fastest in the solar system.:

  • Jupiter.
  • Saturn.

They complete the day in 10 hours.

The Earth rotates around its axis in 23 hours 56 minutes. Plus an additional 4 minutes are required for the Sun to return to its original position. The speed of rotation on the surface depends on the point at which the movement is observed.

If we talk about the equator, then the rotation of the Earth reaches 1670 kilometers per hour or 465 meters per second. Calculations are carried out taking into account the fact that in the equator region the circumference of the planet reaches over 40,000 kilometers. If the planet suddenly stops moving, then people and objects will take off at the same speed and fly forward.

Closer to the 30th latitude, the Earth's rotation around its axis decreases to 1,440 kilometers per hour, gradually dropping to 0 kilometers per hour at the poles (the rule works both towards the South and North Poles). This movement remains invisible to people due to the enormous mass of the planet.

In this video you will learn why we do not feel the rotation of the earth.

Significance for humanity

Differences in movement speed have their own practical significance . Countries prefer to build spaceports closer to the equator. Due to the speed of the planet's rotation, less fuel is required to enter orbit, or more payload can be lifted. Moreover, at launch the rocket already has a speed of 1,675 kilometers per hour, so it is easier for it to accelerate to the orbital speed of 28,000 kilometers per hour.

The Moon, through its influence, constantly stabilizes the tilt of the planet’s axis. Because of this, the rotation speed of the planet gradually decreases. Twice a year, in November and April, the length of the day increases by 0.001 seconds.

Time to complete a revolution around the Sun

The Earth's rotation speed around the Sun is about 107,000 kilometers per hour. The planet makes a full revolution in 365 days, 5 hours 48 minutes and 46 seconds, covering about a billion kilometers during this time. Every year an extra five hours accumulate, which astronomers add up and add 366 days every four years - such a year is called a leap year.

If you count it, it turns out that every second the Earth flies about 30 kilometers in outer space. Even the speed of the world's fastest racing car is only about 300 kilometers per hour - this is 350 times less than the speed of the planet in orbit. A person cannot adequately imagine such enormous speeds.

When rotating, a force is generated that could throw a person or object from the surface of the Earth like an object untwisted on a rope. But this is unlikely to happen in the foreseeable future, since this force is almost completely suppressed by gravity and amounts to only 0.03% of it.

Like rotation around an axis, this movement gradually slows down by amounts imperceptible to ordinary people. Also, the axis in the direction of travel gradually deviates throughout the year, so that the regions in which:

  • winter/summer;
  • autumn/spring.

Once upon a time, people believed that the Earth was a stationary body around which the Sun and all other objects revolved. Many years of observations and improvement of technology have made it possible to gradually understand the issue, and now almost all the inhabitants of the planet know at what speed the Earth rotates, and that it itself has to work a lot, exposing its sides to a huge star in order to ensure day/night and winter/summer.

Video

From this video you will learn how and at what speed the Earth rotates around the Sun.

Like other planets of the solar system, it makes 2 main movements: around its own axis and around the Sun. Since ancient times, it was on these two regular movements that time calculations and the ability to compile calendars were based.

A day is the time of rotation around its own axis. A year is a revolution around the Sun. The division into months is also in direct connection with astronomical phenomena - their duration is related to the phases of the Moon.

Rotation of the Earth around its own axis

Our planet rotates around its own axis from west to east, that is, counterclockwise (when viewed from the North Pole.) An axis is a virtual straight line intersecting globe in the area of ​​Northern and South Pole, i.e. the poles have a fixed position and do not participate in rotational movement, while all other location points are on earth's surface rotate, and the rotation speed is not identical and depends on their position relative to the equator - the closer to the equator, the higher the rotation speed.

For example, in the Italian region the rotation speed is approximately 1200 km/h. The consequences of the Earth's rotation around its axis are the change of day and night and the apparent movement of the celestial sphere.

Indeed, it seems that the stars and other celestial bodies of the night sky are moving in the opposite direction to our movement with the planet (that is, from east to west).

It seems like the stars are all around North Star, which is located on an imaginary line - a continuation of the earth’s axis in a northerly direction. The movement of stars is not proof that the Earth rotates around its axis, because this movement could be a consequence of the rotation of the celestial sphere, if we assume that the planet occupies a fixed, motionless position in space.

Foucault pendulum

Irrefutable proof that the Earth rotates on its own axis was presented in 1851 by Foucault, who conducted the famous experiment with a pendulum.

Let's imagine that, being at the North Pole, we set a pendulum into oscillatory motion. The external force acting on the pendulum is gravity, but it does not affect the change in the direction of oscillations. If we prepare a virtual pendulum that leaves marks on the surface, we can make sure that after some time the marks will move in a clockwise direction.

This rotation can be associated with two factors: either with the rotation of the plane on which the pendulum makes oscillatory movements, or with the rotation of the entire surface.

The first hypothesis can be rejected, taking into account that there are no forces on the pendulum that can change the plane of oscillatory movements. It follows that it is the Earth that rotates, and it makes movements around its own axis. This experiment was carried out in Paris by Foucault, he used a huge pendulum in the form of a bronze sphere weighing about 30 kg, suspended from a 67-meter cable. The starting point of the oscillatory movements was recorded on the surface of the floor of the Pantheon.

So, it is the Earth that rotates, and not the celestial sphere. People observing the sky from our planet record the movement of both the Sun and planets, i.e. All objects in the Universe move.

Time criterion – day

A day is the period of time during which the Earth makes a complete revolution around its own axis. There are two definitions of the concept “day”. “Solar day” is the period of time of the Earth’s rotation during which starting point is taken . Another concept - “sidereal day” - implies a different starting point - any star. The length of the two types of days is not identical. The length of a sidereal day is 23 hours 56 minutes 4 seconds, while the length of a solar day is 24 hours.

The different durations are due to the fact that the Earth, rotating around its own axis, also performs an orbital rotation around the Sun.

In principle, the length of a solar day (although it is taken as 24 hours) is not a constant value. This is due to the fact that the Earth's orbital movement occurs at a variable speed. When the Earth is closer to the Sun, its orbital speed is higher; as it moves away from the sun, the speed decreases. In this regard, such a concept as “average solar day” was introduced, namely its duration is 24 hours.

Orbiting the Sun at a speed of 107,000 km/h

The speed of the Earth's revolution around the Sun is the second main movement of our planet. The Earth moves in an elliptical orbit, i.e. the orbit has the shape of an ellipse. When it is in close proximity to the Earth and falls into its shadow, eclipses occur. The average distance between the Earth and the Sun is approximately 150 million kilometers. Astronomy uses a unit to measure distances within the solar system; it is called the “astronomical unit” (AU).

The speed at which the Earth moves in orbit is approximately 107,000 km/h.
The angle formed by the earth's axis and the plane of the ellipse is approximately 66°33', this is a constant value.

If you observe the Sun from Earth, you get the impression that it is the Sun that moves across the sky throughout the year, passing through the stars and stars that make up the Zodiac. In fact, the Sun also passes through the constellation Ophiuchus, but it does not belong to the Zodiac circle.