Basic concepts of the solar system and planets. Solar-terrestrial connections. Planet Earth, its main parameters and their significance for GO. The daily movement of the Earth around the axis and its consequences. The Earth's orbiting around the Sun and its geographic implications.
HE, formed on the planet, is constantly influenced by space and the interior of the Earth. Formation factors can be divided into cosmic and planetary. TO space factors include: the movement of galaxies, the radiation of stars and the Sun, the interaction of planets and satellites, the impact of small celestial bodies - asteroids, comets, meteor showers. TO planetary - orbital motion and axial rotation of the Earth, the shape and size of the planet, the internal structure of the Earth, geophysical fields.
SPACE FACTORS
Space (Universe) - the entire existing material world. It is eternal in time and infinite in space, it exists objectively, regardless of our consciousness. Matter in the Universe is concentrated in stars, planets, asteroids, satellites, comets and other celestial bodies; 98% of all visible mass is concentrated in stars.
In the universe, celestial bodies form systems of varying complexity. For example, the planet Earth with the satellite Moon forms a system. It is included in a larger system - the Solar, formed by the Sun and celestial bodies moving around it - planets, asteroids, satellites, comets. The solar system, in turn, is part of the galaxy. Galaxies form even more complex systems - galaxy clusters. The grandest star system with many galaxies - Metagalaxy - the part of the Universe accessible to humans (visible with the help of devices). According to modern concepts, it has a diameter of about 100 million light years, the age of the Universe is 15 billion years, it includes 10 22 stars.
Distances in the Universe are determined by the following quantities: astronomical unit, light year, parsec.
Astronomical unit is the average distance from the Earth to the Sun:
1 a.u. \u003d 149.6 million km.
A light year is the distance that light travels in a year:
1 St. year \u003d 9.46 x 10 12 km.
Parsec is the distance from which the average radius of the earth's orbit is seen at an angle of 1 '' (annual parallax):
1 pc \u003d 3.26 sv. year \u003d 206 265 AU - 3.08 x 10 13 km.
Stars in the Metagalaxy form galaxies (from the Greek galacticos - milky) are large stellar systems in which the stars are bound by gravity. The assumption that stars form galaxies was expressed by I. Kant in 1755.
Our Galaxy is called Milky Way -a grandiose cluster of stars visible in the night sky as a hazy, milky streak. The dimensions of the galaxy are constantly being refined; at the beginning of the 20th century, the following values \u200b\u200bwere adopted for it: the diameter of the galactic disk is 100 thousand sv. years, thickness - about - 1000 sv. years old. There are 150 billion stars in the Galaxy, more than 100 nebulae. The main chemical element in our Galaxy is hydrogen, ј is helium. The rest of the chemical elements are present in very small amounts. In addition to gas, there is dust in space. It forms dark nebulae. Interstellar dust consists mainly of two types of particles: carbon and silicate. The size of the dust particles ranges from one millionth to one ten-thousandth of a cm. Interstellar dust and gas are the material from which new stars are formed. In gas clouds, under the action of gravitational forces, clumps are formed - the embryos of future stars. The clot continues to shrink until the temperature and density in its center rise to such an extent that thermonuclear reactions begin. From this time on, the gas clot turns into a star. Interstellar dust takes an active part in this process - it contributes to a faster cooling of the gas, it absorbs the energy released during compression and re-radiates it in a different spectrum. The mass of the formed stars depends on the properties and amount of dust.
The distance from the solar system to the galactic center is 23-28 thousand sv. years old. The Sun is at the periphery of the Galaxy. For the Earth, this circumstance is very favorable: it is located in a relatively calm part of the Galaxy and for billions of years does not experience the influence of cosmic cataclysms.
The solar system revolves around the center of the Galaxy at a speed of 200-220 km / s, making one revolution every 180-200 million years. During its entire existence, the Earth has flown around the center of the Galaxy no more than 20 times. On Earth 200 million years - duration tectonic cycle. This is a very important stage in the life of the Earth, characterized by a certain sequence of tectonic events. The cycle begins by sinking the earth's crust. Accumulation of thick sediments, underwater volcanism. Further, tectonic activity intensifies, mountains appear, the outlines of continents change, which, in turn, causes climate change.
solar system consists of a central star - the Sun, nine planets, more than 60 satellites, more than 40,000 asteroids and about 1,000,000 comets. The radius of the solar system to the orbit of Pluto is 5.9 billion km.
The sun - the central star of the solar system. It is the closest star to Earth. The diameter of the Sun is 1.39 million km, and its mass is 1.989 x 10 30 kg. The sun is a yellow dwarf (class G), the age of the sun is estimated at 5-4.6 billion years. The sun rotates around its axis counterclockwise, in the same direction the planets move around the sun. The main substance that forms the sun is hydrogen (71% of the mass of the luminary), helium - 27%, carbon, nitrogen, oxygen, metals - 2%.
The sun emits two main streams of energy - electromagnetic (solar radiation) and corpuscular (solar wind) radiation. The thermal field of the surface of the planets of the solar system is created by solar radiation. Electromagnetic radiation propagates at the speed of light and reaches the surface of the Earth in 8.4 minutes. In the radiation spectrum, invisible ultraviolet radiation (about 7%), visible light radiation (47%), invisible infrared radiation (46%) are emitted. The fraction of the shortest waves and radio waves is less than 1% of the radiation.
A certain amount of solar radiation is suitable for the upper boundary of the atmosphere, this value is called solar constant.
Corpuscular radiation - the flow of charged particles (electrons and protons) coming from the Sun. Its speed is 1500-3000 km / s, it reaches the magnetosphere in a few days. The Earth's magnetic field delays corpuscular radiation and charged particles begin to move along magnetic lines of force.
At the peak of solar activity, the flow of charged particles increases. Approaching the magnetosphere, the flux increases its intensity, and magnetic storms begin on the Earth. At this time, tectonic movements are activated, volcanic eruptions begin. In the atmosphere, the number of atmospheric vortices - cyclones increases, thunderstorms intensify. The most striking and impressive appearance of the bombardment of the atmosphere by solar particles is auroras - a glow of the upper atmosphere caused by the ionization of gases.
Planetsare located from the Sun in the following sequence: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto. All planets have common properties and characteristics. Common properties include the following:
All planets are spherical;
All planets revolve around the Sun in the same direction counterclockwise for an observer looking from the North Pole of the World. This direction is called direct. Almost all satellites and asteroids move in the same direction;
Most planets rotate axially in the same direction - counterclockwise. The exception is Venus and Uranus, they rotate clockwise;
The orbits of most planets are close in shape to a circle, their eccentricity (the ratio of the distance between the center and focus of the ellipse to the length of the semi-major axis) is small, so the planets do not come close to each other, their gravitational effect is small (only Mercury and Pluto have very elongated orbits);
The orbits of all planets are approximately in the same plane of the ecliptic. Moreover, each next planet is about twice as far from the Sun as the previous one.
This pattern was established by two scientists: I. Titius (1729-1796) and I. Bode (1747-1826). According to the Titius-Bode rule, the distance from the Sun to the planet can be determined by the formula:
r \u003d 0.4 + 0.32 n,
where n \u003d 0 for Venus; n \u003d 1 for the Earth; n \u003d 2 for Mars; n \u003d 4 for Jupiter.
This sequence does not include Mercury, Neptune and Pluto; n \u003d 3 corresponds to the asteroid belt, there is no planet at this distance from the Sun. According to one of the hypotheses, it is assumed that the planet Phaethon once existed at this place, but the gravitational effect of Jupiter led to its disintegration.
The planets are conventionally divided into two large groups: terrestrial planets and giant planets.The first group includes Mercury, Venus, Earth, Mars. The second group is formed by Jupiter, Saturn, Uranus, Neptune. Pluto is closer in size and properties to the icy satellites of the giant planets.
Terrestrial planets are distinguished by their close proximity to the Sun, small size, high density of matter (the density of the Earth is 5.5 g / cm 3); their main components are silicates (silicon compounds) and iron, therefore, the terrestrial planets are solids. The planets slowly revolve around their axis (for Mercury, the period of rotation is 58.7 Earth days for Venus - 243, for Mars - a little more than a day). Due to the slow rotation, the polar contraction of the planets is small, i.e. they have a shape close to a ball. The terrestrial planets have a significant orbital speed (Mercury - 48 km / s, Venus - 35 km / s, Mars - 24 km / s). The planets have only three satellites: Earth has the Moon, Mars has Phobos and Deimos.
The giant planets are located at a great distance from the Sun, are large (the size of Jupiter is 142,800 km), but the density of the planets is low (Jupiter is 1.3 g / cm 3). The most common chemical elements on them are hydrogen and helium, therefore, giant planets are gas balls. All giant planets rotate at high speed around their axis, the period of axial rotation of the planets ranges from 10 hours - for Jupiter, up to 17 hours - for Uranus. Due to their rapid rotation, the planets have a large polar compression (Saturn has 1/10). The speed of orbital rotation of the planets is small (Jupiter makes a full revolution around the sun in 11.86 years, and Neptune in 165 years). All planets have rings and a large number of satellites.
In the solar system, 99.9% of the mass is contained in the sun, therefore the main force that controls the movement of bodies in the solar system is the attraction of the sun. Since the planets move around the Sun in the same plane in almost circular orbits, their mutual attraction is small, but it also causes deviations in the motion of the planets. Probably more interaction of the planets occurs when they come close to each other. A phenomenon called the "parade of planets" is known, when most of the planets line up on the same line (2002 - five planets "stood" on one line: Mercury, Venus, Mars, Jupiter, Saturn).
Asteroids (from the Greek astereideis - star-like) - small planets of the solar system They form a thin ring between the orbits of Mars and Jupiter (presumably formed after the destruction of the planet Phaeton or due to clots of the primary gas and dust cloud). Their average distance from the Sun is 2.8 - 3.6 AU. The first asteroid was named Ceres (1801), by 1880, about 200 asteroids were known, now the orbits are calculated for more than 40,000 asteroids. The largest asteroid Ceres has a diameter of 1000 km, the diameter of Pallas - 608, Vesta - 540, Hygia - 450 km. Almost all asteroids have an irregular shape, only the largest ones approach the ball.
Comets (from the Greek kometes - tailed) are small non-luminous bodies of the solar system that become visible only when they approach the sun. They move along strongly elongated ellipses. The number of comets is measured in millions. As they approach the Sun, their "head" and "tail" become sharply separated. The head consists of ice and dust particles. Sodium and carbon ions were found in the rarefied gas-dusty environment of the tail. One of the most famous comets is Halley's comet; every 76 years it appears in the Earth's field of view.
Meteora -the smallest solid bodies weighing several grams that invaded the planet's atmosphere. Small particles of matter, moving at a speed of 11-12 km / s, due to friction in the atmosphere heat up to 1000 0 С, which causes them to glow for several seconds. They burn up in the atmosphere before reaching the surface. Meteors are divided into single and meteor showers. The most famous meteor showers are: Perseids (fall in August), Draconids (October), Leonids (November). If the Earth crosses the orbit of a meteor shower, the particles “hit the planet”, “star rain” begins. The celestial bodies that have fallen to the surface of the planet are called meteorites. The largest meteor crater on Earth has a diameter of 1265 m and is located in Arizona near Diablo Canyon. The most common elements of meteorites are oxygen, iron, silicon, magnesium, nickel, etc.
Solar-terrestrial connections(GO responses to changes in solar activity). The solar-terrestrial relations should include:
Dynamic factor, i.e. a set of phenomena caused by the motion of the Earth around the Sun in its orbit and secular changes in the parameters of motion (first of all, the position of the Earth's axis in space);
The energy factor associated with the intake of solar radiation. At the level of the earth's surface, the variability of the energy factor is determined by known circumstances - the daily rhythm, the change of the season and the state of the atmosphere and the earth's surface;
The material flow of b- and c-particles, i.e. protons and electrons of the "solar wind", which is involved in the material balance of the upper atmosphere (exosphere and ionosphere).
At present, solar activity is associated with the regular formation of spots, torches, flares, prominences in the Sun's atmosphere. In the middle of the 19th century. Swiss astronomer R. Wolff calculated a quantitative indicator of solar activity, known throughout the world as the Wolf number. The level of solar activity changes with a frequency of about 11 years. The main aspect of the Sun's influence on the Earth, the energy base of solar-terrestrial connections, is the flow of solar radiation, the energy of electromagnetic and corpuscular radiation. On the way to the Earth's surface, solar radiation overcomes several obstacles: the interplanetary medium, the neutral atmosphere, the ionosphere and the geomagnetic field. Simultaneously with the 11-year cycle, a secular, more precisely 80-90-year cycle of solar activity takes place. Inconsistently superimposing on each other, they make noticeable changes in the processes taking place in GO. In particular, a correlation has been established between the 11-year cycle of solar activity and earthquakes, fluctuations in the level of lakes, rivers, groundwater; the frequency of auroras, the intensity of thunderstorm activity, air temperature, atmospheric pressure; the yield of agricultural crops, the frequency of epidemic diseases, the mortality of the population, etc. The impact of solar activity on the general circulation in the troposphere is great. It was found that its intensity changes during the maxima of 11-year cycles, and with it the type of atmospheric circulation.
PLANETARY FACTORS
Planet Earth.Earth is the third planet from the Sun in the solar system and the largest planet in the terrestrial group. Together with the Moon, the earth forms a double planet.
The Earth revolves around the Sun in an orbit, the ellipticity of which is rather weakly expressed. The average orbital radius is 149.6 million km, at perihelion it decreases to 147, 117, and at aphelion it increases to 152, 083 million km. The orbital speed is 29.765 km / s, the orbital period is 365.24 average solar days. The planet rotates around an axis inclined to the orbital plane at an angle of 66 0 33/22 //, making a revolution in 23 hours 56 minutes. 4.1 sec.
The moon is located from the Earth at an average distance of 384 400 thousand km. The Earth and the Moon move jointly around the common center of the system in orbits, the radii of which are inversely proportional to the masses of these bodies.
The position of the Earth in space, physical fields, surface structure, shape and size of a celestial body have a significant impact on its interaction with the Cosmos, in which one of the components is the effect of the Cosmos on the Earth.
The distance from the Earth to the Sun and the cross-sectional area of \u200b\u200bour planet determine the most important energy parameter - the amount of solar radiation entering the upper boundary of the atmosphere. The Earth intercepts 0.5 x 10 -9 part of solar radiation, this amount of energy provides and maintains a thermodynamic environment characteristic of the earth's surface.
The density of the Earth's matter depends on the position of the Earth in the row of planets, and, taking into account its size, also the mass.
Average density of the Earth's matter \u003d 5.5 g / cm 3;
The volume of the Earth \u003d 1.08 x 10 12 km 3;
Earth mass \u003d 5.98 x 10 24 kg; (this mass is enough to hold the atmosphere);
Earth area \u003d 510 million km 2;
Average radius of the Earth \u003d 6371.032 km.
The earth has a gravitational, magnetic and thermal field. The potential gravitational field is due to the mass of the Earth. The maximum value of the gravitational potential in the vertical direction is observed at a depth of about 100 km from the Earth's surface.
The magnetic field includes several components, of which the dipole component is the most pronounced. The axis of the magnetic dipole deviates from the axis of rotation by an angle of about 11 0, and the field itself migrates to the west.
The thermal field is due to internal heat sources. An increase in temperature with depth is observed (the geothermal gradient in the upper part of the earth's crust is on average 3 0 С / 100 m), therefore, the heat flux is directed from the depths to the surface.
The atmosphere as a filter of electromagnetic radiation and the ocean as a condenser of moisture are of great importance for ensuring the constancy of the thermodynamic situation on the earth's surface. An essential astronomical factor of this constancy is the circular shape of our planet's orbit. The contraction of the orbit (its eccentricity is only 0.0167) is close to zero, so the amount of electromagnetic energy coming from the Sun changes insignificantly during the year, and does not affect the temperature of the earth's surface and its changes throughout the year.
The figure of the earth -a model concept, some idealization with the help of which they strive to describe the shape of the planet. Depending on the purpose of the description, they use different models of the shape of the planet - different figures. Let us arrange the known models in a row from the most general to more and more detailed, considering them as successive approximations to the true shape of the Earth.
1.First approximation - sphere... This is the roughest and most general model of the shape of our planet. The sphere does not have a pronounced single axis of symmetry - all its axes are equal, there are countless numbers of them, just like equators. However, the Earth, as already noted, has one axis of rotation and an equatorial plane - the plane of symmetry (as well as the plane of symmetry of the meridians). This discrepancy between the spherical model of the Earth and its real shape is noticeably manifested in the study of the horizontal structure of the GO, which is characterized by pronounced zonality and known symmetry about the equator (with elements of dissymmetry).
2.The second approximation - ellipsoid of revolution... The type of symmetry of the ellipsoid of revolution corresponds to the above features of the Earth's shape (pronounced axis, equatorial plane of symmetry, meridional planes). This model is used in higher geodesy to calculate coordinates, build cartographic grids, and other calculations.
Semi-major axis \u003d 6378.160 km;
Semi-minor axis \u003d 6356.777 km;
The difference between the semiaxes of the ellipsoid of revolution \u003d 21 km.
3.The third approximation - triaxial cardioidal ellipsoid of rotation. The northern polar radius is 30-100 m larger than the southern one.
4.Fourth approximation - geoid. Geoid is a level surface that coincides with the average level of MO and is the locus of points in space that have the same gravity potential. Theoretically, the surface of the geoid at each point is perpendicular to the direction of gravity (i.e., the plumb line) and is identified with the average position of the calm water surface in the oceans and open seas. Continued mentally also under the continents. The surface of the geoid is convex everywhere (which corresponds to the convexity of the oceanic surface). Despite the complexity of its surface, a geoid differs little from a spheroid. Deviations, with some exceptions, are no more than + - 100 m, i.e. the surface of the geoid rarely protrudes more than 100 m above the surface of the spheroid and rarely sinks below the surface of the spheroid by more than the same amount. The average deviation of the geoid from the most successfully selected earth ellipsoid does not exceed + - 50 m.
The earth makes many movements at the same time. In geography, it is customary to take into account and analyze three of them: orbital motion, daily rotation and motion of the Earth-Moon system.
Orbital motion of the Earth.Around the Sun, the Earth moves in an elliptical orbit (length 934 million km) at a speed of 30 km / s. At aphelion (the farthest point from the star) the distance to the Sun is 152 x 10 6 km and falls on July 5, and six months later, at perihelion (January), it decreases and is 147 x 10 6 km. The Earth makes a complete revolution around the Sun during the year \u003d 365 days. 6 hours 9 minutes 9 sec.
Geographic consequences of the annual movement of the earth:
1. The Earth's axis is inclined with respect to the orbital plane and forms an angle with it equal to 66 0 33 /. In the process of movement, the axis moves translationally, so 4 characteristic points appear in the orbit:
March 21 and September 23 - days of equinoxes - the inclination of the earth's axis is neutral in relation to the Sun, and the areas of the planet facing it are uniformly illuminated from pole to pole. At all latitudes during these periods, the duration of the day and night is 12 hours.
June 21 and December 22 - days of summer and winter solstices - the plane of the equator is tilted relative to the sun's ray at an angle of 23 0 27 /, the Sun at this moment is at its zenith over one of the tropics.
(2) The tilt of the earth's axis to the orbital plane is associated with the presence of such characteristic parallels as the tropics and polar circles. The polar circle is a parallel, the latitude of which is equal to the angle of inclination of the earth's axis to the plane of the orbit (66 0 33 /). The tropic is a parallel, the latitude of which complements the tilt angle of the earth's axis to a straight line (23 0 27 /). The polar circles are the boundaries of the distribution of the polar day and polar night. The tropics are the boundaries of the zenith position of the sun at noon. In the tropics, the sun is at its zenith once, in the space between them - twice a year.
2.Changing seasons. Winter, spring, summer, autumn - joint venture; summer, autumn, winter and spring - UP. The uneven distribution of the year between the seasons is characteristic (spring contains 92.8 days, summer - 93.6, autumn - 89.8, winter - 89.0), which is explained by the division of the Earth's elliptical orbit by the lines of solstices and equinoxes into unequal parts, for the passage of which different times are required.
3. Formation of lighting belts, which are distinguished by the height of the Sun above the horizon and the duration of illumination. IN hot belt, located between the tropics, the Sun is at its zenith at noon twice a year. On the lines of the tropics, the Sun is at its zenith only once a year: in the Northern Tropic (Tropic of Cancer), the Sun is at its zenith at noon - June 22, in the Southern Tropic (Tropic of Capricorn) - on December 22.
Between the tropics and the polar circles stand out two moderate belts. In them, the Sun never stands at its zenith, the length of the day and the height of the Sun above the horizon vary greatly throughout the year.
Between the polar circles and the poles are located two cold zones, there are polar days and nights here. Consequently, there are days in a year when the Sun does not appear at all over the horizon or does not sink below the horizon.
4. The change of seasons determines the annual rhythm in GO. In a hot zone, the annual rhythm depends mainly on changes in moisture, in a moderate zone - on temperature, in a cold zone - on lighting conditions.
The daily rotation of the Earth around the axis and its consequences.The earth rotates from west to east counterclockwise, completing a full revolution per day. The axis of rotation is deflected by 23 0 27 / from the perpendicular to the plane of the ecliptic. Average angular velocity of rotation, i.e. the angle by which the point on the earth's surface is displaced is the same for all latitudes and is 15 0 in 1 hour. Linear velocity, i.e. the path traversed by a point per unit of time depends on the latitude of the place. The geographic poles do not rotate, where the speed is zero. At the equator, each point passes the longest path and has the highest speed - 455 m / s. The speed is different on one meridian, the same on one parallel.
The geographic consequences of the Earth's diurnal rotation are:
1. Change of day and night, i.e. change during the day in the position of the Sun relative to the horizon plane of a given point. This change is associated with the diurnal rhythm of solar radiation, the intensity of which depends on the angle of inclination of the earth's axis, the rhythms of heating and cooling of the local air circulation, and the vital activity of living organisms.
2.Different at the same moment local time on different meridians (difference 4 minutes for each degree of longitude).
3.Existence coriolis forces(deflecting action of the Earth's rotation). The Coriolis force is always perpendicular to movement, directed to the right in the northern hemisphere and to the left in the southern. Its value depends on the speed and mass of the moving body, as well as on the latitude of the place:
where m is body weight; x is the linear velocity of the body; w is the angular velocity of the Earth's rotation (it is important only in the secular aspect, for short periods of time the angular velocity is assumed to be constant); c - latitude of the place.
At the equator, the Coriolis force is zero, and its magnitude increases towards the poles. The Coriolis force promotes the formation of atmospheric vortices, affects the deflection of sea currents. Thanks to it, the right banks of the rivers in the joint venture and the left banks in the SP are washed away.
4. Compression of the terrestrial spheroid, which is explained by the simultaneous action on any point of the planet of two forces: gravity (directed towards the center) and centrifugal (perpendicular to the axis of rotation), which give the force of gravity. Gravity is the vector difference between gravity and centrifugal force. The centrifugal force rises from zero at the poles to its maximum value at the equator. In accordance with the decrease in centrifugal force from the equator to the pole, the force of gravity increases in the same direction and reaches a maximum at the pole (equal to the force of gravity).
Our planet Earth is inimitable and unique, in spite of the fact that the planets are open and a number of other stars. Like other planets in the solar system, Earth formed from interstellar dust and gases... Its geological age - 4.5-5 billion years. Since the beginning of the geological stage, the Earth's surface has been divided into continental ledges and ocean trenches... A special granite-metamorphic layer was formed in the earth's crust. When gases were released from the mantle, the primary atmosphere and hydrosphere were formed.
Natural conditions on Earth turned out to be so favorable that with empty billion years since the formation of the planet on it life appeared.The emergence of life is due not only to the characteristics of the Earth as a planet, but also its optimal distance from the Sun ( about 150 million km)... For planets closer to the Sun, the flow of solar heat and light is too great and heats their surfaces above the boiling point of water. Planets farther away from Earth receive too little solar heat and are too cold. For planets whose mass is much less than that of the Earth, the gravitational force is so small that it does not provide the ability to maintain a sufficiently powerful and dense atmosphere.
During the existence of the planet, its nature has changed significantly. Tectonic activity periodically intensified, the size and shape of land and oceans changed, space bodies fell to the surface of the planet, ice sheets appeared and disappeared repeatedly. However, these changes, although they influenced the development of organic life, did not significantly disturb it.
The uniqueness of the Earth is associated with the presence of a geographical envelope that arose as a result of the interaction of the lithosphere, hydrosphere, atmosphere and living organisms.
In the observed part of outer space, another celestial body similar to the Earth has not yet been discovered.
The Earth, like other planets in the solar system, has spherical shape. The ancient Greeks were the first to speak about sphericity ( Pythagoras ). Aristotle observing lunar eclipses, he noted that the shadow cast by the Earth on the Moon always has a rounded shape, which prompted the scientist to think about the sphericity of the Earth. Over time, this idea was substantiated not only by observations, but also by accurate calculations.
In the end 17th century Newton suggested the polar compression of the Earth due to its axial rotation. Measurements of the lengths of meridian segments near the poles and the equator, carried out in the middle XVIII centuryproved the "oblateness" of the planet at the poles. It was determined that the equatorial radius of the Earth is 21 km longer than its polar radius. Thus, of the geometric bodies, the figure of the Earth most resembles ellipsoid of revolution , not a ball.
Circular voyages, an increase in the distance of the visible horizon with height, etc. are often cited as proof of the sphericity of the Earth. Strictly speaking, this is only evidence of the Earth's convexity, and not its sphericity. 
The scientific proof of the sphericity are images of the Earth from space, geodetic measurements on the Earth's surface and lunar eclipses.
As a result of the changes carried out in various ways, the main parameters of the Earth were determined:
average radius - 6371 km;
equatorial radius - 6378 km;
polar radius - 6357 km;
circumference of the equator - 40,076 km;
surface area - 510 million km 2;
weight - 5976 ∙ 10 21 kg.
Land- the third planet from the Sun (after Mercury and Venus) and the fifth in size among other planets of the Solar system (Mercury is about 3 times smaller than Earth, and Jupiter is 11 times larger). The Earth's orbit is elliptical. The maximum distance between the Earth and the Sun is 152 million km, minimum - 147 million km
blog. site, with full or partial copying of the material, a link to the source is required.
The planets of the solar system
According to the official position of the International Astronomical Union (IAS), the organization that assigns names to astronomical objects, there are only 8 planets.
Pluto was excluded from the category of planets in 2006. since in the Kuiper belt there are objects that are larger / or equal in size to Pluto. Therefore, even if it is taken for a full-fledged celestial body, then it is necessary to add Eris to this category, which has almost the same size with Pluto.
As defined by MAC, there are 8 known planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
All planets are divided into two categories depending on their physical characteristics: the terrestrial group and the gas giants.
Schematic representation of the location of the planets
Terrestrial planets
Mercury
The smallest planet in the solar system has a radius of only 2,440 km. The period of revolution around the Sun, for ease of understanding, equated to the Earth's year, is 88 days, while Mercury manages to complete a revolution around its own axis only one and a half times. Thus, his day lasts approximately 59 Earth days. For a long time it was believed that this planet was all the time turned to the Sun by the same side, since the periods of its visibility from the Earth were repeated with a frequency approximately equal to four Mercury days. This misconception was dispelled with the advent of the possibility of using radar research and conducting constant observations using space stations. The orbit of Mercury is one of the most unstable, changing not only the speed of movement and its distance from the Sun, but also the position itself. Anyone interested can observe this effect.
Mercury in color, image from MESSENGER spacecraft
The proximity to the Sun has caused Mercury to experience the largest temperature fluctuations among the planets of our system. The average daytime temperature is about 350 degrees Celsius, and the nighttime temperature is -170 ° C. Sodium, oxygen, helium, potassium, hydrogen and argon were found in the atmosphere. There is a theory that he was previously a satellite of Venus, but so far this remains unproven. He has no satellites of his own.
Venus
The second planet from the Sun, the atmosphere of which is almost entirely carbon dioxide. It is often called the Morning Star and the Evening Star, because it is the first of the stars that becomes visible after sunset, just as before dawn it continues to be visible even when all other stars have disappeared from sight. The percentage of carbon dioxide in the atmosphere is 96%, nitrogen in it is relatively small - almost 4%, and water vapor and oxygen are present in very small quantities.
Venus in the UV spectrum
This atmosphere creates a greenhouse effect, the surface temperature is therefore even higher than that of Mercury and reaches 475 ° C. It is considered the most leisurely, the Venusian day lasts 243 Earth days, which is almost equal to a year on Venus - 225 Earth days. Many call it the sister of the Earth because of its mass and radius, the values \u200b\u200bof which are very close to those of the Earth. The radius of Venus is 6052 km (0.85% of the Earth). There are no satellites, like Mercury.
The third planet from the Sun and the only one in our system where there is liquid water on the surface, without which life on the planet could not have developed. At least life is as we know it. The radius of the Earth is 6371 km and, unlike other celestial bodies of our system, more than 70% of its surface is covered with water. The rest of the space is occupied by continents. Another feature of the Earth is the tectonic plates hidden under the planet's mantle. At the same time, they are able to move, albeit at a very low speed, which over time causes a change in the landscape. The speed of the planet moving along it is 29-30 km / sec.
Our planet from space
One revolution on its axis takes almost 24 hours, and the full orbital passage lasts 365 days, which is much longer in comparison with the nearest neighboring planets. The Earth's day and year are also taken as a standard, but this was done only for the convenience of perception of time intervals on the other planets. The Earth has one natural satellite - the Moon.
Mars
The fourth planet from the Sun, known for its tenuous atmosphere. Since 1960, Mars has been actively explored by scientists from several countries, including the USSR and the USA. Not all exploration programs have been successful, but water found in some areas suggests that primitive life on Mars exists, or has existed in the past.
The brightness of this planet allows you to see it from Earth without any instruments. Moreover, once every 15-17 years, during the Opposition, it becomes the brightest object in the sky, eclipsing even Jupiter and Venus.
The radius is almost half that of the Earth and is 3390 km, but the year is much longer - 687 days. He has 2 satellites - Phobos and Deimos .
An illustrative model of the solar system
Attention! Animation works only in browsers that support the -webkit standard (Google Chrome, Opera or Safari).
The sun
The sun is a star, which is a hot ball of incandescent gases at the center of our solar system. Its influence extends far beyond the orbits of Neptune and Pluto. Without the Sun and its intense energy and heat, there would be no life on Earth. There are billions of stars, like our Sun, scattered throughout the Milky Way galaxy.
Mercury
Scorched by the Sun, Mercury is only slightly larger than Earth's satellite Moon. Like the Moon, Mercury is practically devoid of an atmosphere and cannot smooth out the traces of impact from falling meteorites, therefore, like the Moon, it is covered with craters. The daytime side of Mercury gets very hot on the Sun, while on the night side the temperature drops hundreds of degrees below zero. There is ice in the craters of Mercury, which are located at the poles. Mercury makes one revolution around the Sun every 88 days.
Venus
Venus is a world of monstrous heat (even more than on Mercury) and volcanic activity. Similar in structure and size to Earth, Venus is covered in a thick and toxic atmosphere that creates a strong greenhouse effect. This scorched world is hot enough to melt lead. Radar images through the mighty atmosphere have revealed volcanoes and warped mountains. Venus rotates in the opposite direction from the rotation of most planets.
Earth is an ocean planet. Our home, with its abundance of water and life, makes it unique in our solar system. Other planets, including several moons, also have ice deposits, atmosphere, seasons and even weather, but only on Earth did all these components come together in such a way that life became possible.
Mars
Although details of the surface of Mars are difficult to see from Earth, telescope observations show that Mars has seasons and white spots at the poles. For decades, people believed that the bright and dark areas on Mars were patches of vegetation and that Mars might be a suitable place for life, and that water exists in the polar caps. When the spacecraft Mariner 4 flew off Mars in 1965, many of the scientists were shocked to see photographs of the gloomy planet covered in craters. Mars turned out to be a dead planet. Later missions, however, revealed that Mars holds many mysteries that still remain to be solved.
Jupiter
Jupiter is the most massive planet in our solar system, with four large moons and many small moons. Jupiter forms a kind of miniature solar system. To turn into a full-fledged star, Jupiter had to become 80 times more massive.
Saturn
Saturn is the farthest of the five planets known before the invention of the telescope. Like Jupiter, Saturn is composed primarily of hydrogen and helium. Its volume is 755 times that of the Earth. Winds in its atmosphere reach speeds of 500 meters per second. These fast winds, combined with the heat rising from the planet's interior, are causing the yellow and golden streaks we see in the atmosphere.
Uranus
The first planet found with a telescope, Uranus was discovered in 1781 by astronomer William Herschel. The seventh planet is so far from the Sun that one revolution around the Sun takes 84 years.
Neptune
The distant Neptune revolves almost 4.5 billion kilometers from the Sun. It takes 165 years for one revolution around the Sun. It is invisible to the naked eye due to its great distance from Earth. It is interesting that its unusual elliptical orbit intersects with the orbit of the dwarf planet Pluto, which is why Pluto is inside the orbit of Neptune for about 20 years out of 248 during which it makes one revolution around the Sun.
Pluto
Tiny, cold and incredibly distant, Pluto was discovered in 1930 and has long been considered the ninth planet. But after the discoveries of Pluto-like worlds that were even further away, Pluto was transferred to the category of dwarf planets in 2006.
Planets are giants
There are four gas giants located beyond the orbit of Mars: Jupiter, Saturn, Uranus, Neptune. They are found in the outer solar system. They are distinguished by their massiveness and gas composition.
Planets of the solar system, not scaled
Jupiter
The fifth from the Sun and the largest planet in our system. Its radius is 69912 km, it is 19 times larger than the Earth and only 10 times smaller than the Sun. The year on Jupiter is not the longest in the solar system, it lasts 4333 Earth days (less than 12 years). His own day has a duration of about 10 Earth hours. The exact composition of the planet's surface has not yet been determined, but it is known that krypton, argon and xenon are present on Jupiter in much larger quantities than on the Sun.
It is believed that one of the four gas giants is actually a failed star. This theory is supported by the largest number of satellites, of which Jupiter has many - as many as 67. To imagine their behavior in the planet's orbit, a sufficiently accurate and precise model of the solar system is needed. The largest of them are Callisto, Ganymede, Io and Europa. At the same time, Ganymede is the largest satellite of the planets in the entire solar system, its radius is 2634 km, which is 8% larger than the size of Mercury, the smallest planet in our system. Io differs in that it is one of three satellites with an atmosphere.
Saturn
The second largest planet and the sixth in the solar system. Compared to other planets, the composition of chemical elements is most similar to the Sun. The surface radius is 57350 km, the year is 10 759 days (almost 30 Earth years). The day here lasts a little longer than on Jupiter - 10.5 Earth hours. By the number of satellites, it is not much behind its neighbor - 62 versus 67. The largest satellite of Saturn is Titan, just like Io, which has an atmosphere. Slightly smaller in size, but no less famous from this - Enceladus, Rhea, Dione, Tethys, Iapetus and Mimas. It is these satellites that are the objects for the most frequent observation, and therefore we can say that they are the most studied in comparison with the rest.
For a long time, the rings on Saturn were considered a unique phenomenon inherent only to him. It has only recently been found that rings are present in all gas giants, but in others they are not so clearly visible. Their origin has not yet been established, although there are several hypotheses about how they came about. In addition, more recently it was discovered that Rhea, one of the satellites of the sixth planet, also possesses a kind of rings.
A planet is a body revolving around a star, shining with light reflected from it and having a size larger than that of asteroids, this definition corresponded to our previous ideas. But a number of discoveries in the 1990s. made it insolvent. Beyond the orbit of Neptune, in the Kuiper Belt, astronomers have found hundreds of very large icy bodies. Planets were found near some stars whose orbits were different from others in the solar system. Brown dwarfs and planetary bodies have also been discovered drifting alone through the dark interstellar space.
In August 2006, the International Astronomical Union (IAU) concluded that the planet is an object that revolves around a star and is so large that it took a spheroidal shape and "has no neighbors comparable in mass near its orbit." This definition removed Pluto from the list of planets, changing our attitude towards the structure of both the Solar and other planetary systems formed by accretion in rotating disks. Small particles stick together, forming large formations, the mutual attraction of which makes them unite again and again. As a result, several massive bodies (planets) and many small bodies (asteroids and comets) are formed, representing the remnants of the substance from which the planets were formed. Thus, the term "planet" designates a specific class of celestial bodies.
What is the solar system? What is the solar system made of? The sun and all bodies revolving around it form a SOLAR SYSTEM. The solar system includes nine major planets: MERCURY, VENUS, EARTH, MARS - these are terrestrial planets; JUPITER, SATURN, URANUS, NEPTUNE are the giant planets; AND PLUTO. Also in the solar system are Satellites of these planets and SMALL PLANETS, they are also called asteroids, and COMETS.
In ancient times, people noticed in the night sky a pale luminous strip stretching across the entire sky. She reminded them of spilled milk. According to legend, this is the merit of Hera, who descended to Earth. The luminous strip was called the Milky Way Then, much later, thanks to Galileo's observations, it became known that the Milky Way is a set of distant and therefore dim stars. They merge into one dim glow. Then the hypothesis arose that the Sun, all visible stars, including the stars of the Milky Way, belong to one huge system. This system was called the Galaxy (spelled with a capital letter). The name was given precisely in honor of the Milky Way: the word "Galaxy" comes from the ancient Greek concept meaning "milkweed road". Galaxy The name of our Galaxy is also trivial - the Milky Way
But it's not always easy to judge the building you are inside. So it is with our Galaxy: there were very long disputes about its size, mass, structure of the arrangement of stars. Only relatively recently, in the twentieth century, all kinds of research have allowed man to judge all this. The fact that our galaxy is not alone helped us a lot; our universe is usually defined as the totality of everything that exists physically. It is a set of space and time, all forms of matter, physical laws and constants that govern them. However, the term Universe can be interpreted differently as space, the world or nature.
Why does the Earth rotate? Everyone knows that our planet rotates around its axis, it, in turn, revolves around the sun, and the sun, along with the planets, revolves around the center of our galaxy. Now think about why? Where is the force that makes this whole carousel spin? It has now been established that the speed of rotation of the earth around its axis is gradually decreasing. It would seem that this is the answer to the question. Previously, the earth was "untwisted" and now it rotates by inertia. But calculations show that with such an approach, it would have stopped long ago. The same question arises about the sun, why does it rotate, and even carries all the planets with it? The latest space exploration has led to conclusions about the presence of massive black holes in the centers of galaxies. There is a huge black hole at the center of our galaxy. Judging by the fact that all the stars in the galaxy revolve around its center, it can be assumed that the culprit of the rotation is a massive black hole. But the question remains unanswered again, why does the black hole rotate? The most interesting thing is, where do they all get the energy for this rotation? After all, the law of conservation of energy has not been canceled, and the expenditure of this energy must be simply colossal.
What is the Moon? The Earth and the Moon in Comparison. The satellite of the Earth, the Moon, makes one revolution around the Earth in the same time during which it makes one revolution around its axis. Therefore, we always see only one side of the moon. The reverse side of our satellite was only seen for the first time in 1959, when the automated space station circled the moon and photographed it. The moon ball is about four times smaller than the Earth. But the earth is much denser and heavier than the moon.
The South Pole is the point at which the imaginary axis of the Earth's rotation intersects its surface in the Southern Hemisphere. Earth's Southern Hemisphere The South Pole is located within the Polar Plateau of Antarctica at an altitude of 2800 meters. The thickness of the ice in the area of \u200b\u200bthe South Pole is 2840 meters. The average annual air temperature is 48.9 ° C (maximum 14.7 ° C, minimum 74.3 ° C). Polar Plateau Antarctica meters Amundsen-Scott Station (South Pole)
The North Pole is the point at which the Earth's imaginary axis of rotation intersects its surface in the Northern Hemisphere. The North Pole is located in the central part of the Arctic Ocean, where the depth does not exceed 4000 m. Powerful multiyear pack ice drifts around the North Pole all year round. The average temperature in winter is about 40 ° С, in summer it is mostly about 0 ° С. In September 2007, a record low ice level was recorded at the North Pole. According to the specialists of the National Data Center for Snow and Ice Research, in 2008 the Arctic ice of the pole may completely melt. Nevertheless, the world has already met the year 2009, but the ice remained in place.
Equator - a line of section of the earth's surface by a plane passing through the center of the earth, perpendicular to the axis of its rotation. Equator length km. On the equator line, day is always equal to night. The equator divides the globe into the Northern and Southern Hemispheres. The equator serves as the starting point for calculating the geographic latitude (latitude of the equator - 0 degrees). Latin Aequator - equalizer
1 of 21
Presentation on the topic:
Slide No. 1
Slide Description:
Slide No. 2
Slide Description:
Most people now take it for granted that the sun is at the center of the solar system, but the heliocentric concept did not appear immediately. In the II century A.D. Claudius Ptolemy proposed a model with the Earth in the center (geocentric). According to his model, the Earth and other planets are stationary, while the sun revolves around them in an elliptical orbit. Ptolemy's system has been considered faithful by astronomers and religion for several hundred years. Only in the 17th century, Nicolaus Copernicus developed a model for the structure of the solar system, in which the sun was in the center instead of the earth. The new model was rejected by the church but gradually gained acceptance because it provided a better explanation for the observed phenomena. Oddly enough, Copernicus's initial measurements were no more accurate than Ptolemy's, only they made much more sense.
Slide No. 3
Slide Description:
Slide No. 4
Slide Description:
Slide No. 5
Slide Description:
SOLAR SYSTEM The solar system is a group of celestial bodies, including the Earth, orbiting and gravitationally associated with a star called the Sun. The Sun's suite includes nine planets, about 50 satellites, more than 1000 comets observed, and thousands of smaller bodies known as asteroids and meteorites).
Slide No. 6
Slide Description:
Sun The sun is the central celestial body of the solar system. This star is a hot ball - I myself am close to the Earth. Its diameter is 109 times that of the Earth. It is located at a distance of 150 million km from the Earth. The temperature inside it reaches 15 million degrees. The mass of the Sun is 750 times greater than the mass of all planets moving around it combined.
Slide No. 7
Slide Description:
Jupiter Jupiter is the fifth planet from the Sun, the largest planet in the solar system. Jupiter has 16 satellites, as well as a ring about 6 thousand km wide, almost closely adjacent to the planet. Jupiter does not have a solid surface, scientists suggest that it is liquid or even gaseous. Due to the great distance from the Sun, the temperature on the surface of this planet is -130 degrees.
Slide No. 8
Slide Description:
Mercury Mercury is the closest planet to the Sun. The surface of Mercury, covered with a basaltic-type substance, is rather dark, very similar to the surface of the Moon. Along with craters (usually shallower than on the Moon) there are hills and valleys. The height of the mountains can reach 4 km. Above the surface of Mercury there are traces of a very rarefied atmosphere, containing, in addition to helium, also hydrogen, carbon dioxide, carbon, oxygen and noble gases (argon, neon). The proximity of the Sun causes the planet's surface to heat up to +400 degrees.
Slide No. 9
Slide Description:
Saturn Saturn, the sixth planet from the Sun, the second largest planet after Jupiter in the solar system; belongs to the giant planets, consists mainly of gases. Almost 100% of its mass consists of hydrogen and helium gas. The surface temperature is approaching -170 degrees. The planet does not have a clear solid surface, optical observations are hampered by the opacity of the atmosphere. Saturn has a record number of satellites, now about 30 are known. It is believed that the rings are formed by various particles, potassium, blocks of various sizes covered with ice, snow, frost.
Slide No. 10
Slide Description:
Venus Venus, the second planet from the Sun, is Earth's twin in the solar system. These two planets have approximately the same diameter, mass, density and soil composition. On the surface of Venus, craters, faults and other signs of intense tectonic processes taking place on it were found. Venus is the only planet in the solar system whose proper rotation is opposite to the direction of its revolution around the sun. Venus has no satellites. In the sky, it shines brighter than all the stars and is clearly visible to the naked eye. Surface temperature +5000, because an atmosphere composed mainly of CO2
Slide No. 11
Slide Description:
Uranus Uranus, the seventh planet from the Sun, belongs to the giant planets. For many centuries, Earth's astronomers have known only five "wandering stars" - planets. 1781 was marked by the discovery of another planet, called Uranus, which became the first to be discovered with a telescope. Uranus has 18 satellites. Uranus' atmosphere is mainly composed of hydrogen, helium and methane.
Slide No. 12
Slide Description:
Earth is the third planet from the Sun. Earth is the only planet in the solar system with an oxygen-rich atmosphere. Thanks to its unique natural conditions in the Universe, it has become a place where organic life arose and developed. According to modern concepts, the Earth was formed about 4.6–4.7 billion years ago from a protoplanetary cloud captured by the gravity of the Sun. The formation of the first, the most ancient of the studied rocks took 100-200 million years. ____
Slide No. 13
Slide Description:
On the basis of seismic studies, the Earth is conditionally divided into three regions: crust, mantle and core (in the center). The outer layer (crust) has an average thickness of about 35 km. The Earth's mantle, which is also called the silicate shell, extends to a depth of about 35 to 2885 km. It is separated from the bark by a sharp border. Another boundary between the mantle and the outer core discovered by seismic methods is located at a depth of 2775 km. Finally, at depths over 5120 km, there is a solid inner core, which accounts for 1.7% of the Earth's mass.
Slide No. 14
Slide Description:
The rotation of the Earth around its own axis occurs in 23 hours 56 minutes 4.1 s. The linear velocity of the Earth's surface at the equator is about 465 m / s. The axis of rotation is tilted to the plane of the ecliptic at an angle of 66 ° 33 "22" "This tilt and the annual rotation of the Earth around the Sun determine the change of seasons, which is extremely important for the Earth's climate, and its own rotation - the change of day and night.
Slide Description:
Neptune Neptune is the eighth planet from the Sun. It has a magnetic field. Astronomers believe that below the atmosphere, at a depth of about 10,000 km, Neptune is an "ocean" made up of water, methane and ammonia. There are 8 satellites moving around Neptune. The largest of them is Triton. This planet is named after the ancient Roman god of the sea. The location of Neptune was calculated by scientists, and only then it was discovered with a telescope in 1864.
Slide No. 17
Slide Description:
Mars Mars is the fourth planet from the Sun. A qualitatively new level of Mars research began in 1965, when spacecraft began to be used for these purposes, which first flew around the planet and then (since 1971) and descended to its surface. The mantle of Mars is enriched in sulphurous iron, noticeable amounts of which have also been found in the studied surface rocks. The planet got its name in honor of the ancient Roman god of war. The seasons are changing on the planet. Has two satellites.
Slide No. 18
Slide Description:
Pluto Pluto is the ninth largest planet from the Sun in the Solar System. In 1930, Clyde Tombaug discovered Pluto close to one of the regions predicted by theoretical calculations. Pluto's mass, however, is so small that the discovery was made by accident as a consequence of intensive exploration of the part of the sky to which the predictions had drawn attention. Pluto is about 40 times farther from the Sun than Earth. Pluto spends almost 250 Earth years for one revolution around the Sun. Since its opening, it has not yet managed to complete a single full turn.
Slide No. 19
Slide Description:
The most, the most, the most ... Mercury is the planet closest to the sun Pluto is the planet farthest from the sun Venus has the highest surface temperature Life exists only on Earth On Venus a day is longer than a year Jupiter is the largest planet Saturn has the largest number of moons Pluto is the smallest planet Jupiter is the coldest The planet Saturn has the most unusual and colorful appearance.
Slide No. 20
Slide Description:
Test questions What is the largest planet? What is the smallest planet? The planet closest to the sun? The planet on which life exists? The planet that was first discovered with a telescope? Which planet was named after the god of war? Which planet has the brightest rings? A celestial body emitting light and warmth? What planet was named after the goddess of war and beauty? A planet that was discovered "at the tip of a feather"
Slide No. 21
Slide Description: