How is the apparent movement of the planets. Test. The apparent movement of the planets and the sun. The movement of the planets in the zodiac

O dust of the worlds! O swarm of sacred bees!
I examined, measured, weighed, counted,
Gave names, made maps, estimates
But the horror of the stars from knowledge did not die out.
M. Voloshin

Lesson 1/7

Topic: Apparent motion of the planets.

Target: To acquaint students with the composition of the solar system, the concepts of cosmic and celestial phenomena associated with the circulation of planets around the Sun and the visible movement of other cosmic bodies: the loop-like movement of the planets, configurations and their types, periods of revolution.

Tasks :
1. educational: systematization of concepts about celestial phenomena: the apparent movement and configurations of the planets, observed as a result of the mutual movement and location of the heavenly bodies relative to the earthly observer; a detailed consideration of the causes and characteristics of the cosmic phenomenon of the revolution of planets around the Sun and its consequences - celestial phenomena: the apparent movement of the inner and outer planets in the celestial sphere and their configurations (upper and lower conjunctions, elongations, oppositions, quadratures), atmospheric refraction.
2. nurturing: the formation of a scientific worldview in the course of acquaintance with the history of human knowledge and explanation of daily observed celestial phenomena; fight against religious prejudice.
3. Educational: the formation of skills to perform exercises on the application of the basic formulas of spherical astronomy in solving relevant calculation problems and apply a moving map of the starry sky, star atlases, reference books, the Astronomical calendar to determine the position and conditions of visibility of celestial bodies and the flow of celestial phenomena.

Know 1st level (standard) - a general description of the composition of the solar system (information about the bodies and characteristic patterns), types of configuration, the concept of synodic and sidereal circulation periods and their relationship. 2nd level- a general description of the composition of the solar system (information about the bodies and characteristic patterns), types of configuration, the concept of synodic and sidereal periods of revolution and their relationship, formulas expressing the relationship between sidereal and synodic periods of revolution and rotation of planets;
Be able to: 1st level (standard)- determine the type of configuration and make the simplest calculations of the periods of revolution, use astronomical calendars, reference books and a moving map of the starry sky to determine the conditions for the onset and flow of these celestial phenomena. 2nd level- determine the type of configuration, use astronomical calendars, reference books and a moving map of the starry sky to determine the conditions for the onset and flow of these celestial phenomena, solve problems related to calculating the position and visibility conditions of planets, taking into account formulas expressing the relationship between sidereal and synodic periods of their circulation and rotation .

Equipment: Table “Solar system”, slide film “Structure of the solar system”, transparencies: loop-like motion of the planet, configuration and phases of the inner planets, model of the planetary system, film “Visible movement of celestial bodies”, film “Planetary system”, “ Loop of Mars. Table - “The composition of the solar system”. PCZN. CD- "Red Shift 5.1" ( Excursions-2. Sun, Earth and Moon - Zigzags of the planets; the principle of finding a celestial object at a given point in time, Lectures- Wandering planets).

Interdisciplinary communication: mathematics (development of computational skills and geometric representations), students' initial idea of ​​the structure of the solar system obtained in natural history and history courses.

During the classes:

1.Repetition of the material (8-10min)

BUT) Questions:

• Calendar message.
• Solution of problem No. 4 (p. 29).
• Solution of problem No. 5 (p. 29).
• Solution of problem No. 7 (p. 29).
• Relationship between time and longitude. Universal and other types of time.

B) Rest:1. Crossword

2. Specify the causes of celestial phenomena, marking in front of each option of the question the correct number of the answer option, for example: A1; B2; B3, etc.

3. Work on issues.

1. The azimuth of the star is 45°, and the height is 60°. In which side of the sky did the light shine? [in the West]
2. Determine the constellation in which the star is located α=4 h 14 m, δ=16°28". [α- Taurus - Aldebaran]
3. When during the day the zenith distance of the Sun is 90 o? [sunrise, sunset]
4. How many days did he keep in 1918 in the Russian Federation in connection with the reform, calendar?
5. The planet is visible at a distance of 120 o from the Sun. Is this planet upper or lower? [top]
6. March 20, 1997 was the opposition of Mars. What constellation was Mars in? [Pisces - point γ]
7. Will the configuration of the constellations visible from Earth be preserved if an astronaut observes the starry sky from Mars? [Yes]

2. New material (15min)
1. The composition of the solar system:

1. Planets - Today, 8 large planets with satellites and rings are known: Mercury, Venus, Earth (with the Moon), Mars (with Phobos and Deimos), Jupiter (with a ring and at least 63 satellites), Saturn (with a powerful ring and at least 60 satellites) - these planets are visible to the naked eye; Uranus (discovered in 1781, with a ring and at least 27 satellites), Neptune (discovered in 1846, with a ring and at least 13 satellites).
2. dwarf planets- Pluto (discovered in 1930, with Charon and 2 more satellites = was a planet until 08/24/2006), Ceres (the first asteroid discovered in 1801), and Kuiper belt objects: Xena (Xena, object 2003UB313 - official name 136199 Eris (Eris )) and Sedna (object 90377), located beyond the orbit of Pluto and discovered in 2003.
3. Minor planets - asteroids= (the first Ceres was discovered in 1801 - transferred to the category of dwarf planets from 24.08.2006), located mainly in 4 belts: the main one - between the orbits of Mars and Jupiter, the Kuiper belt - beyond the orbit of Neptune, the Trojans: in the orbit of Jupiter and Neptune . Dimensions less than 800 km. Nearly 400,000 are now known.
4. Comets- small bodies up to 100 km in diameter, a conglomerate of dust and ice, moving in very elongated orbits. The Oort cloud (reservoir of comets) is located at the periphery of the solar system.
5. Meteor bodies- small bodies from grains of sand to stones several meters in diameter (formed from comets and crushing of asteroids). Small ones burn up when entering the earth's atmosphere, and those that reach the Earth are meteorites.
6. interplanetary dust- from comets and crushing of asteroids. Small ones are pushed to the periphery of the solar system by solar pressure, while larger ones are attracted by the planets and the Sun.
7. interplanetary gas- from the Sun and planets, very discharged. The "solar wind" - a stream of plasma (ionized gas from the Sun) propagates in it.
8. Electromagnetic radiation and gravitational fields- The solar system is permeated with the magnetic fields of the Sun and planets, gravitational fields and electromagnetic waves of various wavelengths generated by the planets and the Sun.

2. Loop-like motion of the planets

More than 2000 years before the NE, people noticed that some stars moved around the sky - they were later called "wandering" by the Greeks - planets. They included the Moon and the Sun. The current name of the planets is borrowed from the ancient Romans. It turned out that the planets wander in the zodiac constellations. But I could only explain N. Copernicus at the beginning of the 16th century by a visible display on the celestial sphere due to the movement of the Earth and planets with different speeds around the Sun. The trajectory of a celestial body is called its orbit. The velocities of the planets in their orbits decrease with the distance of the planets from the Sun. The planes of the orbits of all the planets of the solar system lie near the plane of the ecliptic, deviating from it: Mercury by 7 o, Venus by 3.5 o; others have even less slope. In relation to the orbit and the conditions of visibility from the Earth, the planets are divided into internal(Mercury, Venus) and external(Mars, Jupiter, Saturn, Uranus, Neptune). The outer planets are always turned to the Earth by the side illuminated by the Sun. The inner planets change their phases like the moon.

3. The configuration of the planets.

Configuration- the characteristic relative position of the planets relative to the Sun and the Earth. Bottom - connection(upper and lower - the planet is on the direct Sun-Earth) and elongation(western and eastern - the greatest angular distance of the planet from the Sun: Mercury-28 o, Venus-48 o - the best time for observing the planets). In inferior conjunction, Venus and Mercury periodically pass over the disk of the sun : Mercury in May and November 13 times in 100 years. The last ones took place on 05/07/2003 and 11/08/2006, and will be on 05/09/2016 and 11/11/2019. Venus in June and December they repeat after 8 and 105.5, or 8 and 121.5 years, the last was on 06/08/2004 and will be on 06/06/2012. Upper - quadrature(western and eastern - a quarter of a circle) and compound (confrontation- when the planet behind the Earth from the Sun is the best time to observe the outer planets, it is completely illuminated by the Sun).

4. Periods of planetary revolution.
During the development of the heliocentric system of the structure of the world N. Copernicus got formulas ( synodic period equations ) to calculate the periods of revolution of the planets and calculated them for the first time.
Sidereal (T - stellar)- the time interval during which the planet makes a complete revolution around the sun in its orbit relative to the stars.
synodic (S) - time interval between two successive identical planetary configurations .

The lower (inner) planets orbit faster than the Earth, and the upper (outer) planets slower. If the planet completes one revolution in a period T, then per day it will shift in orbit by 360 o/t, and the Earth on 360 o / T z. Then for the lower planet the difference in mean displacements is the observed daily displacement 360 o /S = 360 o /T - 360 o /T s or 1 / S \u003d 1 / T - 1 / T s (form. 12), and for the upper 1/S=1/T s - 1/T (for.13) internal external

Astronomical refraction- the phenomenon of refraction (curvature) of light rays when passing through the atmosphere, caused by the optical inhomogeneity of atmospheric air. Due to the decrease in the density of the atmosphere with height, the curved beam of light is bulging towards the zenith. Refraction changes the zenith distance (height) of the luminaries according to the law: r = a*tanz , where: z - zenith distance, a \u003d 60.25 "- the refraction constant for the earth's atmosphere (at t\u003d 0 o C, p= 760 mm. rt. Art.). At the zenith, refraction is minimal - it increases with inclination to the horizon up to 35 "and strongly depends on the physical characteristics of the atmosphere: composition, density, pressure, temperature. Due to refraction, the true height of celestial bodies is always less than their apparent height: refraction "raises" the images of stars above The shape and angular dimensions of the luminaries are distorted: at sunrise and sunset near the horizon, the disks of the Sun and the Moon are "flattened", since the lower edge of the disk rises by refraction more than the upper one. The refractive index of light is distorted depending on the wavelength: with a very clean atmosphere, a person can see a rare "green beam" at sunset or sunrise. Since the distances to the stars incomparably exceed their sizes, we can consider the stars as point sources of light, the rays of which propagate in space along parallel straight lines. The refraction of rays of starlight in atmospheric layers (streams) of different density causes flicker stars - uneven amplification and weakening of their brilliance, accompanied by changes in their color ("play of stars").

The Earth's atmosphere scatters sunlight on random microscopic inhomogeneities of air density, concentrations and rarefactions with dimensions of 10 -3 -10 -9 m. The intensity of light scattering is inversely proportional to the fourth power of the light wavelength (Rayleigh's law). Short waves scatter the most: violet, blue and blue rays, the weakest - orange and red. As a result, the earth's sky has a blue color during the day. It is never completely dark on Earth at night: the light of stars and the long-set Sun scattered in the atmosphere creates a negligible illumination of 0.0003 lux. Daylight hours - days always exceeds the time interval from sunrise to sunset. Scattering of the sun's rays in the earth's atmosphere twilight, a smooth transition from daylight - day to dark - night, and vice versa. Twilight is caused by the illumination of the upper layers of the atmosphere by the sun below the horizon. Their duration is determined by the position of the Sun on the ecliptic and the geographical latitude of the place. Distinguish civil twilight: the period of time from sunset (the upper edge of the solar disk) to its immersion by 6 o -7 o below the horizon; navigational twilight- until the moment the Sun sinks below the horizon by 12 o; astronomical twilight - until the angle is 18 o. At high (± 59.5 o ) latitudes of the Earth, White Nights- the phenomenon of a direct transition of evening twilight into morning twilight in the absence of darkness. Summarized in the table.

III. Fixing the material 8 min)

1. View example #3(page 34).
2. Mars at opposition is visible in the constellation Libra. What constellation is the sun in at this time? (Aries)
3. What constellation is Mercury (Venus) in if the planet is now in upper (lower) conjunction with the Sun? (according to PKZN in the zodiac constellations of the location of the Sun)
4. July 21, 2001 Mercury is at its greatest western elongation. In what constellation at what time of day and how long can this planet be observed? (In the western elongation, the planet is observed in the evening, according to the PKZN Gemini-Taurus, 28 o / 15 o \u003d 1 hour 52 minutes).
5. What are the conditions for seeing the earth from the surface of the moon? Orbits of the satellite of Venus? From the surface of Mars? (Pay attention to the position of the Sun, which interferes with visibility)
6. CD- "Red Shift 5.1":
   = shows (if necessary) the principle of finding an object at a given time and an example for Mars of finding the previous and next opposition. (26.10.2006 and 5.12.2008)
   \u003d in which constellations, what is the phase, magnitude, elongation and angular diameter of the planets, the Sun, the Moon (we find best in the astronomical calendar)
   \u003d which planets are in conjunction with the Sun in October (for 2007 this is Mercury in the lower)
7. What is the length of a year on Mars if 780 d elapses between two oppositions? ( 1/S=1/T s - 1/T, hence T \u003d (T z. S) / (S- T z) \u003d (365.25. 780) / (780-365.25) \u003d 686.9 d)
8. It is most convenient to observe Mercury near its elongations. Why? How often do they repeat if the year on Mercury is 88 d? (not so interferes with the light of the Sun, 1/S=1/T - 1/T s, hence S=(88 . 365.25)/(365.25-88)=115.9 d)
9. Opposition Jupiter was observed on April 30, 1994 at 13.9 hours. When will the next opposition be? Will it be visible?

Solution: According to formula 13 we get S\u003d 1.092 years \u003d 1.092. 365.25=1 year + 34 days. Add to this date and get the confrontation June 2, 1995. According to the PKZN we find - the constellation Ophiuchus between 16 and 17 hours, that is, in the daytime - not visible.

Outcome:
1) What is a configuration? Her types. 2) What is the sidereal and synodic period? 3) The composition of the solar system. 4) Why are the positions of the planets not indicated on star maps? 5) In what constellations should we look for planets in the sky? 6) What planets can be observed against the background of the solar disk? 7) Pass the test, crossword puzzle, message, questionnaire (what they did - what was asked) on the first chapter "Introduction to Astronomy". 8) Grades

Homework:§7; questions and tasks page 35.
Assignments from the collection of Olympiad problems by V.G. Mute:
4.10. On Earth, the solar day is longer than the sidereal day, while on Venus it is the other way around. Why? (to solve it, you need to remember that the Earth rotates around its axis in the opposite direction from the direction in which it revolves around the Sun. Venus is the only planet in the solar system that rotates in the same direction in which it revolves around the Sun. The sun on Venus descends beyond the horizon before the stars, at the same time with which it ascended).
4.13. It is believed that Venus has either morning or evening visibility. Is it possible to observe Venus within one day and in the morning and in the evening? (Answer: "yes". The phenomenon of "double visibility" of Venus is observed in the case of a large difference between the declinations of the Sun and Venus. In this case, in the middle and northern latitudes, Venus rises a little earlier than the Sun, and sets a little later than the Sun).

last modified 14.10.2009

the movement of the planets relative to the stars, visible from the earth, in the direction from 3 to east, corresponding to the direction of their revolution around the sun.

• - a horse or hand tool for weed control between rows, consists of a hinged frame, on which the working bodies are strengthened, depending on the operation being performed ...

  Agricultural dictionary-reference book

• - Orbits of the terrestrial planets. Seasons on earth...

  Geographic atlas

• - the observed movement of the planets relative to the stars ...

  Astronomical dictionary

• - from west to east. - backward - from east to west. - stars proper - the movement of a star in the celestial sphere relative to the more distant stars surrounding it ...

  Astronomical dictionary

• - the movement of the planets relative to the stars from East to West, visible from the Earth, opposite to the direction of their circulation around the Sun. P. d. - a consequence of the movement of the planet and the Earth in their orbits. Wed Direct movement...

  Astronomical dictionary

• - planets - the movement of planets relative to stars from West to East, visible from the Earth, corresponding to the direction of their circulation around the Sun ...

  Astronomical dictionary

• - the movement of a planet, comet or other celestial body in orbit around the Sun or a satellite around its planet in the direction from west to east ...

  Scientific and technical encyclopedic dictionary

• - the movement of the planets relative to the stars, visible from the Earth, in the direction from East to 3., opposite to the direction of their revolution around the Sun. P.d.p. is a consequence of the movement of the planet and the Earth in their orbits ...

  Natural science. encyclopedic Dictionary

• - a hand or horse plow-type tool for loosening the soil and cutting weeds in row-spacing row crops ...
• - the movement of the planets relative to the stars from east to west, as seen from the earth, i.e., in the direction opposite to the direction of rotation of the planets around the sun ...

  Great Soviet Encyclopedia

• - the movement of the planets relative to the stars, visible from the Earth, occurring from W to E, that is, in the direction of their actual revolution around the Sun ...

  Great Soviet Encyclopedia

• - REVERSAL motion of the PLANETS - the apparent movement of the planets in the direction from east to west, opposite to the direction of their circulation around the Sun ...
• - planets - the movement of the planets relative to the stars from west to east, visible from the Earth, corresponding to the direction of their revolution around the Sun ...

  Big encyclopedic dictionary

• - PLANET a, m. planette f. plow Hand or horse tool for loosening the soil and cutting weeds in row-spacing row crops. BAS-1. Planets. American cultivator. TE 1939 11 763...

  Historical Dictionary of Gallicisms of the Russian Language

• - PLANET, planet, husband. . Hand or horse-drawn implement for clearing weeds between rows...

  Explanatory Dictionary of Ushakov

• - plan...

  Russian spelling dictionary

"DIRECT MOTION OF THE PLANETS" in books

What is the main difference between the planets of the terrestrial group and the rest of the planets of the solar system?

author Kondrashov Anatoly Pavlovich

What is the main difference between the planets of the terrestrial group and the rest of the planets of the solar system? The planets of the solar system are divided into two types: terrestrial planets (Mercury, Venus, Earth and Mars) and gaseous planets (Jupiter, Saturn, Uranus and Neptune). terrestrial planets

06. Direct and reverse rotation of planets

From the book Astronomy and Cosmology author Danina Tatiana

06. Direct and reverse rotation of the planets Thanks to astronomical observations, we know that most of the planets in our solar system rotate in the forward direction - that is, counterclockwise. And this direction of rotation is the same as the direction of rotation

planetary motion

From the book The Big Book of Secret Knowledge. Numerology. Graphology. Palmistry. Astrology. divination the author Schwartz Theodore

§ 1. Movement of the planets and astrology

From the book Critical Study of the Chronology of the Ancient World. Antiquity. Volume 1 author Postnikov Mikhail Mikhailovich

§ 1. Movement of the planets and astrology Planets Five planets are visible in the sky with the naked eye: Mercury, Venus, Mars, Jupiter, Saturn. Observations show that 1. All planets are located near the ecliptic.2. Their positions among the stars are constantly changing (the planets are said to

1.4 MOTION OF THE PLANETS

From the book Volume 4. Planetology, part I. Sun and Moon author Vronsky Sergey Alekseevich

1.4 MOTION OF THE PLANETS From the point of view of an earthly observer, all the planets, except for the Sun and the Moon, periodically slow down their course, stop and begin the reverse movement, which is called retrograde. This phenomenon is explained by the difference in the periods of revolution of the planets around

4.3.5. planetary motion

From the book Volume 1. Introduction to Astrology author Vronsky Sergey Alekseevich

4.3.5. Movement of the planets From the point of view of an earthly observer, the planets, except for the Sun and the Moon, have different (visible from the Earth) directions of movement. Sometimes you can observe the so-called loop-like motion of the planet, which is explained by the difference in the periods of rotation of the planets around

23. Movement. Movement as a way of existence of matter. Formation, change, development. Basic forms of movement

From the book Cheat Sheets on Philosophy author Nyukhtilin Victor

23. Movement. Movement as a way of existence of matter. Formation, change, development. The main forms of movement Movement in philosophy is any change in general. This concept includes: 1. Processes and results of interactions of any kind (mechanical, quantum,

Principles of action of matter; the attraction of bodies and the motion of the planets explained from these principles

From the book American Enlightenment. Selected works in two volumes. Volume 1 author Franklin Benjamin

Principles of action of matter; the attraction of bodies and the motion of planets, explained from these principles ON THE PRINCIPLES OF THE ACTION OF MATTERSection I. On the Essential Properties and Differences of Things1. We have no knowledge of substances, or of anything that exists, or of any thing separate from action.

5.3. The movement of the planets in the zodiac

author

5.3. The movement of the planets in the zodiac Before we talk about how, using a horoscope, you can unambiguously (or almost unambiguously) encrypt the date of an event, let us recall some well-known information from astronomy. Observing the night sky from Earth,

5.11. Points of the approximate location of the planets on the Egyptian zodiac ("best points") and taking into account the order of the planets

From the book New Chronology of Egypt - I [with illustrations] author Nosovsky Gleb Vladimirovich

5.11. Points of the approximate location of the planets on the Egyptian zodiac (“best points”) and taking into account the order of the planets In addition to the boundaries of longitude, for each planet we will also determine the approximate position of this planet in the sky each time. That is, that position in the real sky,

What is the main difference between the planets of the terrestrial group and the rest of the planets of the solar system?

From the book The Newest Book of Facts. Volume 1 [Astronomy and astrophysics. Geography and other earth sciences. Biology and Medicine] author Kondrashov Anatoly Pavlovich

What is the main difference between the planets of the terrestrial group and the rest of the planets of the solar system? The planets of the solar system are divided into two types: terrestrial planets (Mercury, Venus, Earth and Mars) and gaseous planets (Jupiter, Saturn, Uranus and Neptune). terrestrial planets

Retrograde motion of the planets

From the book Great Soviet Encyclopedia (PO) of the author TSB

Direct motion of the planets

From the book Great Soviet Encyclopedia (PR) of the author TSB

Movement Three Turn of the torso and cloud-like movement of the arms

From the book of Taijiquan. The Art of Harmony and the Method of Life Extension by Wang Ling

Movement Three Turning the torso and cloud-like movement of the arms 1. Gradually turn the torso to the left towards the direction of the south with a slight deviation to the east. Slowly bend the left leg at the knee and transfer the center of gravity to it, gradually raise the heel

The planets are divided according to their apparent movements at the bottom of the group: lower (Mercury, Venus) and upper (all the rest except the Earth).

The movements in the constellations of the lower and upper planets are different. Mercury and Venus are always in the sky, either in the same constellation as the Sun, or in a neighboring one. At the same time, they can be located both east and west of the Sun, but no further than 18-28 ° (Mercury) and 45-48 ° (Venus). The greatest angular distance of a planet from the Sun to the east is called its greatest eastern elongation, to the west - its greatest western elongation. At eastern elongation, the planet is visible in the west, in the rays of the evening dawn, shortly after sunset, and sets some time after it.

Then, moving backwards (i.e. from east to west, at first slowly, and then faster, the planet begins to approach the Sun, hides in its rays and ceases to be sawed. At this time, the lower connection of the planet with the Sun occurs; the planet passes between the Earth and the Sun. The ecliptic longitudes of the Sun and the planet are equal. Some time after the inferior conjunction, the planet becomes visible again, but now in the east, in the rays of the dawn, shortly before sunrise. At this time, it continues to move backward, gradually moving away from the Sun "Having slowed down the rate of retrogression and reached the greatest western elongation, the planet stops and changes its direction of motion to a direct one. Now it moves from west to east, at first slowly, then faster. Its distance from the Sun decreases, and finally it hides in the morning rays Sun At this time, the planet passes behind the Sun, the ecliptic longitudes of both luminaries are again equal - it comes from the top This is the conjunction of the planet with the Sun, after which, after some time, it is again visible in the west in the rays of the evening dawn. Continuing to move in a straight line, it gradually slows down its speed.

Having reached the maximum eastern distance, the planet stops, changes the direction of its movement to the reverse, and everything repeats from the beginning. Thus, the lower planets make, as it were, “oscillations” around the Sun, like a pendulum around its middle position.

The positions of the planets relative to the Sun described above are called planetary configurations.

7.2. Explanation of the configurations and apparent movements of the planets

During their movement in orbits, the planets can occupy various positions relative to the Sun and the Earth. Suppose that at some moment (Fig. 24) the Earth T occupies a certain position in its orbit relative to the Sun C. The lower or upper planet can be at this moment at any point in its orbit.

If the lower planet V is located in one of the four points V 1, V 2, V 3 or V 4 indicated on the drawing, then it is visible from the Earth in the lower (V 1) or upper (V 3) conjunction with the Sun, in the greatest western (V 2) or at greatest eastern (V 4) elongation. If the upper planet M is located at points M 1, M 2, M 3 or M 4 of its orbit, then it is visible from the Earth in opposition (M 1), in conjunction (M 3), in the western (M 2) or eastern ( M 4) quadrature.

The essence of explaining the forward and backward movements of the planets is to compare the orbital linear velocities of the planet and the Earth.

When the upper planet (Fig. 25) is near the conjunction (M 3), then its speed is directed in the direction opposite to the Earth's speed (T 3). From the Earth, the planet will appear to move in direct motion, i.e. in the direction of its actual movement, from right to left. In this case, its speed will seem increased. When the upper planet is near opposition (M 1), then its speed and the speed of the Earth are directed in the same direction. But the linear velocity of the Earth is greater than the linear velocity of the upper planet, and therefore, from the Earth, the planet will appear to be moving in the opposite direction, i.e. backwards, from left to right.

Similar reasoning explains why the lower planets (Mercury and Venus) near the lower conjunction (V 1) move backwards among the stars, and near the upper conjunction (V 3) - in direct motion (Fig. 26).

Since ancient times, people have observed in the sky such phenomena as the apparent rotation of the starry sky, the change in the phases of the moon, the rising and setting of heavenly bodies, the apparent movement of the Sun across the sky during the day, solar eclipses, the change in the height of the Sun above the horizon during the year, lunar eclipses.

It was clear that all these phenomena are connected, first of all, with the movement of celestial bodies, the nature of which people tried to describe with the help of simple visual observations, the correct understanding and explanation of which took shape over the centuries. After the recognition of the revolutionary heliocentric system of the world of Copernicus, after Kepler formulated the three laws of motion of celestial bodies and destroyed centuries-old naive ideas about the simple circular motion of the planets around the Earth, proved by calculations and observations that the orbits of the motion of celestial bodies can only be elliptical, it finally became clear that the apparent motion of the planets consists of:

1) movement of the observer on the surface of the Earth;

2) rotation of the Earth around the Sun;

3) proper motions of celestial bodies.

The complex apparent motion of the planets in the celestial sphere is due to the revolution of the planets of the solar system around the sun. The very word "planet" in translation from ancient Greek means "wandering" or "tramp".

The trajectory of a celestial body is called its orbit. The velocities of the planets in their orbits decrease with the distance of the planets from the Sun. The nature of the movement of the planet depends on which group it belongs to.

Therefore, in relation to the orbit and the conditions of visibility from the Earth, the planets are divided into internal(Mercury, Venus) and external(Mars, Jupiter, Saturn, Uranus, Neptune, Pluto), or, respectively, in relation to the Earth's orbit, to the lower and upper ones.

The outer planets are always turned to the Earth by the side illuminated by the Sun. The inner planets change their phases like the moon. The greatest angular distance of a planet from the Sun is called elongation . The greatest elongation for Mercury is 28°, for Venus it is 48°. The planes of the orbits of all the planets of the solar system (except Pluto) lie near the plane of the ecliptic, deviating from it: Mercury by 7º, Venus by 3.5º; others have even less slope.

At eastern elongation, the inner planet is visible in the west, in the rays of the evening dawn, shortly after sunset. With western elongation, the inner planet is visible in the east, in the rays of dawn, shortly before sunrise. The outer planets can be at any angular distance from the Sun.

The phase angle of Mercury and Venus varies from 0° to 180°, so Mercury and Venus change phases in the same way as the Moon. Near inferior conjunction, both planets have the largest angular dimensions, but look like narrow crescents. At the phase angle ψ = 90°, half of the disk of the planets is illuminated, phase Φ = 0.5. In superior conjunction, the lower planets are fully illuminated, but are poorly visible from the Earth, as they are behind the Sun.

So, when observing from the Earth, the movement of the planets around the Sun is also superimposed on the movement of the Earth in its orbit, the planets move across the sky from east to west (direct movement), then from west to east (reverse movement). The moment of change of direction is called standing . If you put this path on the map, you get the loop . The size of the loop is the smaller, the greater the distance between the planet and the Earth. The planets describe loops, and not just move back and forth in a single line, solely due to the fact that the planes of their orbits do not coincide with the plane of the ecliptic. Such a complex loop-like character was first noticed and described using the example of the apparent motion of Venus (Figure 1).

Figure 1 - "Venus Loop".

It is a known fact that the movement of certain planets can be observed from the Earth only at a strictly defined time of the year, this is due to their position over time in the starry sky.

The characteristic mutual arrangements of the planets relative to the Sun and the Earth are called planetary configurations. The configurations of the inner and outer planets are different: for the lower planets these are conjunctions and elongations (the largest angular deviation of the planet's orbit from the orbit of the Sun), for the upper planets these are quadratures, conjunctions and oppositions.

Let's talk more specifically about each of the types of configurations: configurations in which the inner planet, the Earth and the Sun line up in one line are called conjunctions (Fig. 2).

Rice. 2. Planet configurations:
Earth in superior conjunction with Mercury
in inferior conjunction with Venus and in opposition to Mars

If A is the Earth, B is the inner planet, C is the Sun, the celestial phenomenon is called bottom connection. In the "ideal" inferior conjunction, Mercury or Venus transits across the disk of the Sun.

If A is the Earth, B is the Sun, C is Mercury or Venus, the phenomenon is called top connection. In the "ideal" case, the planet is covered by the Sun, which, of course, cannot be observed due to the incomparable difference in the brightness of the luminaries.

For the Earth-Moon-Sun system, a new moon occurs in the lower conjunction, and a full moon occurs in the upper conjunction.

The limiting angle between the Earth, the Sun and the inner planet is called greatest removal or elongation and is equal to: for Mercury - from 17њ30 "to 27њ45"; for Venus - up to 48º. The inner planets can only be observed near the Sun and only in the mornings or evenings, before sunrise or just after sunset. The visibility of Mercury does not exceed an hour, the visibility of Venus is 4 hours (Fig. 3).

Rice. 3. Elongation of planets

The configuration in which the Sun, Earth and outer planet line up is called (Fig. 2):

1) if A is the Sun, B is the Earth, C is an external planet - opposition;

2) if A is the Earth, B is the Sun, C is an external planet - by the conjunction of the planet with the Sun.

The configuration in which the Earth, the Sun and the planet (Moon) form a right-angled triangle in space is called quadrature: eastern when the planet is 90º east of the Sun and western when the planet is 90º west of the Sun.

The motion of the inner planets on the celestial sphere is reduced to their periodic separation from the Sun along the ecliptic either to the east or to the west by the angular distance of elongation.

The motion of the outer planets on the celestial sphere is of a more complex loop-like nature. The speed of the visible movement of the planet is uneven, since its value is determined by the vector sum of the own velocities of the Earth and the outer planet. The shape and size of the planet's loop depends on the speed of the planet relative to the Earth and the inclination of the planet's orbit to the ecliptic.

Now we introduce the concept of specific physical quantities that characterize the motion of the planets and allow us to make some calculations: The sidereal (stellar) period of revolution of a planet is the time interval T, during which the planet makes one complete revolution around the Sun in relation to the stars.

The synodic period of a planet's revolution is the time interval S between two successive configurations of the same name.

For the lower (inner) planets:

For the upper (outer) planets:

The duration of the mean solar day s for the planets of the solar system depends on the sidereal period of their rotation around its axis t, the direction of rotation and the sidereal period of revolution around the Sun T.

For planets that have a direct direction of rotation around their axis (the same in which they move around the Sun):

For planets with the opposite direction of rotation (Venus, Uranus).