This is a system of planets, in the center of which is a bright star, the source of energy, heat and light - the Sun.
According to one theory, the Sun was formed along with the solar system about 4.5 billion years ago as a result of the explosion of one or more supernovae. Initially, the solar system was a cloud of gas and dust particles, which, in motion and under the influence of their mass, formed a disk in which a new star, the Sun, and our entire solar system arose.
At the center of the solar system is the Sun, around which nine large planets revolve in orbits. Since the Sun is displaced from the center of the planetary orbits, then during the cycle of revolution around the Sun, the planets either approach or move away in their orbits.
There are two groups of planets:
Terrestrial planets: and . These planets are small in size with a rocky surface, they are closer than others to the Sun.
Giant planets: and . These are large planets, consisting mainly of gas, and they are characterized by the presence of rings consisting of ice dust and many rocky pieces.
But does not fall into any group, because, despite its location in the solar system, it is located too far from the Sun and has a very small diameter, only 2320 km, which is half the diameter of Mercury.
Planets of the solar system
Let's start a fascinating acquaintance with the planets of the solar system in order of their location from the Sun, and also consider their main satellites and some other space objects (comets, asteroids, meteorites) in the gigantic expanses of our planetary system.
Rings and moons of Jupiter: Europa, Io, Ganymede, Callisto and others...
The planet Jupiter is surrounded by a whole family of 16 satellites, and each of them has its own, unlike other features ...
Rings and moons of Saturn: Titan, Enceladus and more...
Not only the planet Saturn has characteristic rings, but also on other giant planets. Around Saturn, the rings are especially clearly visible, because they consist of billions of small particles that revolve around the planet, in addition to several rings, Saturn has 18 satellites, one of which is Titan, its diameter is 5000 km, which makes it the largest satellite of the solar system ...
Rings and moons of Uranus: Titania, Oberon and others...
The planet Uranus has 17 satellites and, like other giant planets, thin rings encircling the planet, which practically do not have the ability to reflect light, therefore they were discovered not so long ago in 1977 quite by accident ...
Rings and moons of Neptune: 
Triton, Nereid and others...
Initially, before the exploration of Neptune by the Voyager 2 spacecraft, it was known about two satellites of the planet - Triton and Nerida. An interesting fact is that the Triton satellite has a reverse direction of orbital motion, and strange volcanoes were also discovered on the satellite that spewed nitrogen gas like geysers, spreading a dark mass (from liquid to vapor) for many kilometers into the atmosphere. During its mission, Voyager 2 discovered six more satellites of the planet Neptune...
Our arrival and departure are mysterious,-
their goals are all the wise men of the earth
failed to comprehend.
Where is the beginning of this circle, where is the end,
where do we come from, where do we go
from here?
Omar Khayyam
The solar system is a complex of celestial bodies, united not only by the orderliness of movement, but also by the commonality of physical properties. At the center of the solar system is our day star - the Sun. Around it, together with their satellites, 9 large planets circulate: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.
Their physical characteristics are given in table. 10.1 and 10.2.
Mercury- the closest planet to the Sun and the smallest of the terrestrial planets. Its diameter is 0.383 of the Earth's diameter, and its mass is 0.056 of the Earth's mass. The period of rotation of Mercury around its axis is 58.65 Earth days. This is close to 2/3 of the period of the planet's revolution around the Sun (88 Earth days). This means that one day on Mercury lasts two Mercury years. Mercury always faces the Earth with the same hemisphere. In appearance, Mercury resembles the Moon with many of its craters, mountains and seas. Mercury has traces of a highly rarefied atmosphere, which includes hydrogen, helium, oxygen, as well as argon and neon. The surface temperature of the planet ranges from -180 °C to +430 °C. The planet has a weak magnetic field. Mercury has no satellites.
Venus It is the second-most distant planet from the Sun and the closest planet to Earth in the solar system. Visible as an "evening star"
Table 10.1 Physical characteristics of the planets of the solar system
| Planet | Weight, kg | Average density, g / cm 3 | Surface temperature, K | Gravity on the surface, (earth = 1) | Equatorial diameter, km |
| Mercury | 3.15 - 10 23 | 5,44 | 0,38 | ||
| Venus | 4,89 - 10 24 | 5.16 | 0,91 | 12 104 | |
| Earth | 5,98 - 10 24 | 5,52 | 1,00 | 12 756 | |
| Mars | 6,42 - 10 23 | 3,94 | 250-320 | 0,38 | |
| Jupiter | 1,89 - 10 27 | 1,88 | 173 (max) | 2,34 | 140 140 |
| Saturn | 5.68 - 10 26 | 0,71 | 0,93 | 115 600 | |
| Uranus | 8,68 - 10 25 | 1,47 | 90 (max) | 0,85 | 49 400 |
| Neptune | 1,03 - 10 25 | 1,70 | 72 (max) | 1.14 | 49 008 |
| Pluto | 1,40 - 10 24 | 1,30 | 63 (max) | 0,04 |
Table 10.2 Dynamic characteristics of the planets of the solar system
| Planet | Average distance from the Sun, million km | Period of revolution around the Sun, years (days) | Average speed of orbital movement, km/s | Period of rotation around the axis (days and hours) |
| Mercury | 57,91 | 0,24 (88) | 47,87 | 58.6 days |
| Venus | 108,21 | 0,62 (224,7) | 35,00 | 243.16 days |
| Earth | 149,60 | 1,00 (365,24) | 29,79 | 23 h 56 min. 4s |
| Mars | 227,94 | 1,88 (687,0) | 24,13 | 24 hours 37 minutes 23 s |
| Jupiter | 777,80 | 11,86 | 13,05 | 9 hours 50 minutes 30 s |
| Saturn | 1427,00 | 29.46 | 9,65 | 10 hours 14 minutes |
| Uranus | 2869,00 | 84,02 | 6,80 | 10 h 48 min. |
| Neptune | 4496,00 | 164,80 | 5.43 | 15 hours 48 minutes |
| Pluto | 5947,00 | 247,70 | 4,74 | 6.39 days |
in the western side of the sky just after sunset, or as a "morning star" - in the eastern side of the sky shortly before sunrise. Venus is the brightest luminary in the sky after the Sun and the Moon. Venus rotates on an axis not from west to east, as
Earth, and in the opposite direction - from east to west. Venus is enveloped in a dense atmosphere, almost entirely composed of carbon dioxide (97%) with an admixture of nitrogen, oxygen and water vapor. Atmospheric pressure - over 90 atm. The temperature near the surface of the planet reaches +470 °C. The surface of the planet is dry and rocky. It has vast plains, but there are also mountains. Their greatest height reaches 12 km. Apparently, there are many volcanoes. Venus has no natural satellites.
Mars is the fourth planet from the sun in the solar system. In the starry sky, it looks like a non-flickering red dot. Mars is half the size of the Earth in diameter and nine times the mass. The period of rotation of the planet around the axis is 24 hours 37 minutes. 23 p. The inclination of the axis of rotation of Mars to the plane of the orbit is almost the same as that of the Earth (about 25 °), so Mars has a season similar to Earth, although the length of the Martian year is close to 687 Earth days. The atmosphere of Mars is very rarefied and consists mainly of carbon dioxide with an admixture of nitrogen, argon, oxygen and water vapor. Atmospheric pressure at the surface of the planet is 160 times less than at sea level on Earth. Winds and even hurricanes often arise in the atmosphere of Mars, causing dust storms. The average annual temperature of the planet is -70 °С. Under these conditions, there can be no liquid water on Mars, and it exists only in the form of steam, snow or ice. Mars has a magnetic field 500 times weaker than Earth's magnetic field. In pictures taken during the flights of automatic interplanetary stations, the surface of the planet looks like a red, waterless, rock-strewn desert with rugged relief. There are craters on Mars, there are mountains, some of them are extinct volcanoes. The largest volcanic Mount Olympus in the entire solar system rises more than 20 km above the surface of the planet. Mars has two natural satellites - Phobos and Deimos.
Jupiter- the largest planet in the solar system and the fifth in distance from the sun. It got its name in honor of the Roman god of the sky, the Thunderer Jupiter. The mass of the planet is almost 2.5 times the total mass of the other planets
and 318 times the mass of the Earth. The diameter of Jupiter is 11.2 times the diameter of the Earth. Jupiter is 5.2 times farther from the Sun than Earth and takes almost 12 years to complete one orbit. Jupiter rotates around its axis faster than any other planet in the solar system. In a telescope, the planet is seen compressed at the poles with a noticeable row of light and dark bands, which are arranged differently every year. Jupiter is surrounded by a thick hydrogen-helium atmosphere, in the upper layers of which the temperature is about -160 ° C. The peculiarity of this planet is the presence of the famous Great Red Spot - a huge oval-shaped and pink gas formation, larger than the size of the globe. Presumably, it is a grandiose rotating whirlwind. Jupiter has a powerful magnetic field, and is also a source of fairly strong radio emission. 16 moons revolve around Jupiter, the four largest of which were discovered in 1610 by Galileo. In addition to satellites, Jupiter is surrounded by a ring of small stones and dust. It always faces the Earth with an edge, so it is not visible from the Earth.
Saturn is the second largest planet in the solar system. With a mass of approximately 95 Earth masses and a volume of more than 758 Earth volumes, it has the lowest average density of any planet. Saturn's atmosphere contains hydrogen, methane and other gases. Near the top of the clouds, the temperature is about -170 °C. The planet has a magnetic field and is a source of radio emission. Saturn has 17 moons, the largest of which is Titan. One of the well-known and interesting celestial formations is the rings of Saturn.
Uranus- the seventh planet from the Sun in the solar system. This is the first of the planets discovered with a telescope. Uranus is one of the giant planets. In diameter, it is almost 4 times, and in mass - approximately 14.6 times larger than the Earth. The distance from Uranus to the Sun is almost 20 times greater than from the Earth to the Sun, and it makes a complete revolution around our star in 84 years. Uranus, like Venus, revolves around its
axis in the direction from east to west (and not from west to east, like the Earth and other planets). Uranus is highly compressed at the poles. Its atmosphere is half hydrogen. In addition, it contains methane, ammonia and helium. The temperature on the surface of the planet's cloud layer is about -215 °C. Uranus has nine narrow opaque gas and dust rings and 16 satellites.
Neptune- the eighth largest planet in the solar system by distance from the Sun. The diameter of Neptune is 3.81 times the diameter of the Earth, and the mass is 17.2 Earth masses. The planet is highly compressed and rotates rapidly around its axis. It appears to be composed of frozen water and other hydrogen compounds common in space. 20% of the mass falls on silicon and metal compounds. The planet receives 900 times less heat from the Sun than the Earth. The temperature on the surface of Neptune is -200-220 °С The planet is shrouded in a dense hydrogen-helium atmosphere with an admixture of methane and ammonia. Neptune has 8 satellites and rings of the same nature as Jupiter.
Pluto- the smallest among the planets of the solar system known to us and the most distant from the Sun. Pluto was discovered relatively recently. Pluto is 40 times farther from the Sun than the Earth, and receives 1600 times less heat and light from it than our planet. Pluto is a cold, dark and silent world whose surface is covered in methane ice. The temperature of the planet is record low: -230 °C. The rotation period of Pluto is 6.4 days, and the period of revolution is almost 248 years. In 1978, the American astronomer J. Christie discovered one satellite near Pluto, named Charon. It is removed from the planet at a distance of 17,000 km.
The solar system has a number of important features. Let's list the main ones.
1. The vast majority of the total mass of the solar system belongs to the Sun, i.e., the central body. The Sun accounts for 99.87% of the mass of the solar system, so that the force of its attraction almost completely controls the movement of the planets, which revolve around it in orbits close to elliptical
myself. Therefore, the Sun is almost exactly in the center of the planetary orbits.
2. The orbits of all planets and most asteroids are close to circles and lie approximately in the plane of the ecliptic, i.e., in the plane of the earth's orbit. The orbits of Pluto (17°) and Mercury (7°) have the greatest inclination to the ecliptic (Earth's orbit) and the greatest elongation.
3. In terms of size, mass and general structure, large planets are divided into two groups: planets of the Earth type (or terrestrial planets) located inside the asteroid belt, and giant planets (outside it). Pluto occupies a special position, different from the planets of both groups.
Earth-type planets are much smaller than giants in mass and size. They have a higher average density of matter and relatively slow rotation.
The giant planets are tens and hundreds of times more massive than the terrestrial planets. They are surrounded by relatively dense extended atmospheres. Most of the giant planets are made up of hydrogen and helium; the proportion of all other elements in them is much less than that of the terrestrial planets.
4. All planets revolve around the Sun in one direction,
moreover, the direction of their axial rotation, as a rule, coincides
em with the direction of movement along the orbit. The exception is
only Venus and Uranus, which rotate in the opposite
side, and the axis of rotation of Uranus almost lies in the plane
orbits.
These features are associated with the conditions in which the formation of planets took place billions of years ago.
The age of the solar system was determined on the basis of laboratory isotopic analysis of terrestrial rocks, as well as meteorites and samples of lunar soil delivered to Earth by spacecraft. It turned out that the oldest of them have an age of about 4.5 billion years. The age of the Sun, obtained on the basis of the theory of stellar evolution, is estimated at about 5 billion years. Therefore, it is believed that all the planets
formed approximately at the same time - 4.5-5 billion years ago.
According to existing ideas, the substance from which the planets and their satellites arose originally formed a massive disk of cold gas and dust that surrounded the still young Sun. The planets were formed as a result of the growth of clumps that arose under the influence of gravitational forces in this rotating disk. Therefore, now all of them, while maintaining the movement of the disk, revolve around the Sun in the same direction. The density, temperature, and chemical composition of protoplanetary matter were very different in the outer, far from the Sun, and inner, close to it, parts of the disk. This led to a strong difference between the two groups of planets - inner and outer.
The two main reasons that determine the most important properties of each planet are its distance from the Sun and its mass. The greater the average distance of a planet from the Sun, the less energy it receives from it. For this reason, the temperature of the planets drops rapidly with increasing distance from the Sun. Recall that, unlike distant planets, the terrestrial planets located closer to the Sun contain a lot of refractory elements (silicon, iron, etc.). Apparently, this reflects the features of the chemical composition of the protoplanetary gas and dust disk, from the substance of which the planets were formed: the farther from the Sun, the more light gases were contained in the protoplanetary disk. The reason for this is that at greater distances from the Sun, at lower temperatures, molecules of light gases could freeze onto dust particles, while near the Sun, light gases heated up and left the protoplanetary disk.
The mass of a planet determines its ability to hold an atmosphere around it. Gas always tends to expand, and gaseous atmospheres are held around planets only by gravitational attraction to them. But from the atmosphere of any planet there is a continuous leakage of matter into interplanetary space. The reason for this is clear: thermal
movement of gas molecules. The speed of each molecule is constantly changing due to collisions with other molecules. If the speed accidentally exceeds the second cosmic one, then such a molecule can forever leave the rarefied outer layers of the planet's atmosphere. The smaller the mass of the planets, the weaker its gravitational attraction and the faster it loses its atmosphere, since it is easier for the fastest molecules to leave it. It is known from physics that the average speed of the thermal motion of molecules and atoms is proportional, where T is the absolute temperature of the gas, and m 0 is the mass of its molecules (or atoms). Therefore, at any temperature, the molecules of light gases, which have a higher average speed, leave the atmosphere most quickly. Therefore, over time, the mass of the atmosphere and its chemical composition must change. There are very few light gases (hydrogen and helium) left in the atmospheres of the terrestrial planets. Mercury, due to its small mass and high temperature, due to its proximity to the Sun, is almost completely devoid of an atmosphere. The atmosphere of Mars, due to the weakness of its gravitational field, is strongly discharged, and the Moon and satellites of the planets could not keep the gas shell near them at all. The exception is the massive and cold satellite of Saturn - Titan, which has an atmosphere containing a lot of rather heavy gas - nitrogen, and a small satellite of Jupiter - Io. The latter loses the atmosphere continuously, but it is constantly replenished by volcanic eruptions, which, together with the ejection of lava, emit many gases. Apparently, in the terrestrial planets (including the Earth), volcanic eruptions and gas emissions from the interior played a decisive role in the formation of atmospheres when the planets were still young.
On the solid surface of large planets (especially those without an atmosphere) and their satellites, numerous craters are observed - the result of meteorite bombardment. It also happens in our time. However, it was most intense billions of years ago. Bodies such as the Moon, Mercury, Jupiter's satellite Callisto and others, where there are a lot of craters and where they collapsed little, have retained most of
its surface as it was billions of years ago. On Venus, Mars and some satellites (partially on the Moon) there was a process of gradual disappearance of old craters. They could be filled with lava (on the Moon), destroyed under the influence of wind (as, for example, on Mars) or water (as on Earth). Therefore, the study of the surfaces of various planets and satellites makes it possible to learn about their distant history and evolutionary paths.
Strong magnetic fields have been found so far in three planets: Earth, Jupiter and Saturn. Apparently, they are associated with the existence of electric currents in the molten interiors of these planets. If the terrestrial planets Mercury, Venus, Earth and Mars have a relatively high density and consist of heavy elements, then the giant planets Jupiter, Saturn, Uranus and Neptune have a density slightly higher than that of water and consist of light elements hydrogen and helium. They have powerful extended atmospheres that pass into the liquid layer of the surface. For example, Jupiter consists mainly of hydrogen, 18% by mass is helium, there is an admixture of ammonia NH 3 and methane CH 4 (marsh gas). Although the giant planets are cold and lifeless, due to the huge distances between them and the large masses, it has numerous families of satellites. The Saturnian system bears an even more striking resemblance to the solar system as a whole, not only because this planet has 17 moons (more than the number of known planets), but also because it also has large rings - a miniature "asteroid belt". The rings are made up of small particles covered with ice that revolve around Saturn in a disk that is thinner in relation to its width than a sheet of paper. Uranus and Jupiter also have rings, although they are much fainter and therefore difficult to observe. Perhaps Neptune has them too.
In addition to the large planets and their satellites, the solar system includes thousands of small planets - asteroids, located mainly between the orbits of Mars and Jupiter, where they form the so-called asteroid belt. Besides,
in interplanetary space, solid ice bodies surrounded by a gaseous shell move along very elongated orbits - comets and many stones and particles of various sizes: meteors and meteorites (Fig. 10.6).
Asteroids. Most of the asteroids (more than five thousand bodies ranging in size from one kilometer to a thousand kilometers) move between the orbits of Mars and Jupiter. Their orbits, as a rule, do not differ too much from circles. Periodic brightness changes observed in some asteroids indicate that they have an irregular shape, uneven surface and rotate around their axes. The surfaces of asteroids, like those of planetary satellites, must bear traces of impacts from smaller bodies. Asteroids do not have atmospheres.
Comets- these strange celestial wanderers aroused superstitious fear in people more often than any other celestial
body. Most comets move in extremely elongated orbits and approach the Sun for only a short time with each revolution. At perihelion, at the closest approach to the Sun, their brightness increases very much. At this time, they are so active that they lose a significant proportion of their substance and an extended atmosphere (coma) of gas and small dust particles forms around their core. Under the pressure of solar radiation and particles ejected by the Sun, cometary gas and dust leave the head of the comet, giving rise to an extended tail, and even several tails, always of a complex structure. It is likely that comets contributed to the enrichment of the matter of the solar system with such light volatile components as carbon and water, without which life on Earth would be impossible.
The universe is an incredibly vast place, so incredible that even the human imagination cannot grasp the full depth of the immensity of the universe. As for our solar system, by the standards of the Universe, it is only a tiny part of it. Whereas for us, mere mortal inhabitants of a small planet called Earth, the solar system is a very large place, and, despite all the great achievements of astronomy in recent years, much still remains unknown, we are just beginning to approach the borders of our native solar system.
History of exploration of the solar system
Since ancient times, people have looked at the stars, inquisitive minds have pondered their origin and nature. Soon it was noticed that some stars change their position in the starry sky, so the first planets were discovered. The word "planet" itself is translated from ancient Greek as "wanderer". The planets received the names of the gods of the ancient pantheon: Mars, Venus, and so on. Their movement and origin was explained by beautiful poetic myths that are present in all the peoples of antiquity.
At the same time, people of the past believed that the Earth is the center of the universe, planets, other stars, everything revolves around the Earth. Although, of course, already in ancient times there were scientists, such as, for example, Aristarchus of Samos (he is also called the Copernicus of antiquity), who believed that everything was somewhat different. But a real breakthrough in the study of the solar system occurred during the Renaissance and is associated with the names of the outstanding astronomers Nicolaus Copernicus, Giordano Bruno, Johannes Kepler. It was then that the idea was established that our Earth is not the center of the Universe, but only an insignificantly small part of it, that the Earth revolves around the Sun, and not vice versa.
Gradually, all today known planets of the solar system were discovered, as well as their numerous satellites, and much more.
Structure and composition of the solar system
The structure of the solar system can be divided into the following elements:
- The Sun, its center and main energy source, it is the powerful Sun that keeps the planets in their places and makes them rotate in their orbits.
- Terrestrial planets. Scientists astronomers divided the solar system into two sections: the inner solar system and the outer solar system. Four nearby rocky planets were included in the inner solar system: Venus, Earth and Mars.
- The asteroid belt that lies beyond Mars. It is believed that it was formed back in the distant times of the birth of our solar system and consists of various cosmic debris.
- The giant planets, they are also gas giants, which are located in the outer part of the solar system. These are Jupiter, Saturn, and Neptune. Unlike the terrestrial planets, which have a solid surface with a mantle and a core, gas giants are filled mainly with a hydrogen and helium mixture. With a more detailed study, the composition of the planets of the solar system may vary.
- Coiler belt and Aorta cloud. They are located beyond Neptune, and dwarf planets live there, the most famous of which are numerous. Since these areas are very far from us, modern science has very scarce information about them. In general, many features of the structure of the solar system are still poorly understood.
Diagram of the structure of the solar system
Here, the picture clearly shows a visual model of the structure of the solar system.
The origin of the solar system and its evolution
According to scientists, our solar system appeared 4.5 billion years ago as a result of a large gravitational collapse of a giant molecular cloud consisting of helium, hydrogen and a number of heavier chemical elements. Most of this cloud gathered in the center, due to the strong clustering, the temperature rose, and as a result, our Sun was formed.
Due to the high temperature, only solid bodies could exist near the newborn star, and thus the first solid planets appeared, among which is our native Earth. But the planets, which are gas giants, formed at a more distant distance from the Sun, the temperature there was not so high, as a result, large masses of ice formed the gigantic sizes of the planets there.
This picture shows how the evolution of the solar system took place in stages.
Exploring the solar system
The real boom associated with the study of outer space and the solar system began in the middle of the last century, especially with the space programs of the former Soviet Union and the United States: the launch of the first artificial satellites, the flight of the first cosmonauts, the famous landing of American astronauts on the moon (which some skeptics consider to be fake though) and so on. But the most effective method in studying the solar system, then and now, is to send special research probes.
The first artificial Soviet spacecraft, Sputnik 1 (pictured), was launched into orbit back in 1957, where it spent several months collecting data on the Earth's atmosphere and ionosphere. In 1959, the American satellite Explorer joined it, it was he who took the first space photographs of our planet. Then the Americans from NASA launched a number of research probes to other planets:
- Mariner flew to Venus in 1964.
- Mariner 4 arrived at Mars in 1965 and then successfully passed Mercury in 1974.
- In 1973, the Pioneer 10 probe was sent to Jupiter, and scientific study of the outer planets began.
- In 1974, the first probe was sent to Saturn.
- In the 80s of the last century, the Voyager spacecraft, which were the first to fly around the gas giants and their satellites, became a real breakthrough.
Active exploration of outer space continues in our time, so quite recently, in September of this 2017, the Casini spacecraft, launched in 1997, died in the atmosphere of Saturn. During his twenty-year research mission, he made many interesting observations on the atmosphere of Saturn, its satellites and, of course, the famous rings. The last hours and minutes of Casini's life were broadcast live by NASA.
The structure of the solar system, video
And in conclusion, an interesting documentary about our solar system.
solar system- these are 8 planets and more than 63 of their satellites, which are being discovered more and more often, several dozen comets and a large number of asteroids. All cosmic bodies move along their clear directed trajectories around the Sun, which is 1000 times heavier than all the bodies in the solar system combined. The center of the solar system is the Sun - a star around which planets revolve in orbits. They do not emit heat and do not glow, but only reflect the light of the sun. There are currently 8 officially recognized planets in the solar system. Briefly, in order of distance from the sun, we list them all. And now some definitions.
Planet- this is a celestial body that must satisfy four conditions:
1. the body must revolve around a star (for example, around the Sun);
2. the body must have sufficient gravity to have a spherical or close to it shape;
3. the body should not have other large bodies near its orbit;
4. the body should not be a star
Planet satellites. The solar system also includes the Moon and the natural satellites of other planets, which all of them have, except for Mercury and Venus. More than 60 satellites are known. Most of the satellites of the outer planets were discovered when they received photographs taken by robotic spacecraft. Jupiter's smallest moon, Leda, is only 10 km across.
is a star, without which life on Earth could not exist. It gives us energy and warmth. According to the classification of stars, the Sun is a yellow dwarf. The age is about 5 billion years. It has a diameter at the equator equal to 1,392,000 km, 109 times larger than the earth. The rotation period at the equator is 25.4 days and 34 days at the poles. The mass of the Sun is 2x10 to the 27th power of tons, approximately 332950 times the mass of the Earth. The temperature inside the core is about 15 million degrees Celsius. The surface temperature is about 5500 degrees Celsius. According to the chemical composition, the Sun consists of 75% hydrogen, and of the other 25% of the elements, most of all helium. Now let's figure out in order how many planets revolve around the sun, in the solar system and the characteristics of the planets.
The four inner planets (nearest to the Sun) - Mercury, Venus, Earth and Mars - have a solid surface. They are smaller than four giant planets. Mercury moves faster than other planets, being burned by the sun's rays during the day and freezing at night.
Period of revolution around the Sun: 87.97 days. Diameter at the equator: 4878 km.
Rotation period (turn around the axis): 58 days.
Surface temperature: 350 during the day and -170 at night.
Atmosphere: very rarefied, helium.
How many satellites: 0.
The main satellites of the planet: 0.
More like the Earth in size and brightness. Observation of it is difficult because of the clouds enveloping it. The surface is a hot rocky desert. 
Period of revolution around the Sun: 224.7 days.
Diameter at the equator: 12104 km.
Rotation period (turn around the axis): 243 days.
Surface temperature: 480 degrees (average).
Atmosphere: dense, mostly carbon dioxide.
How many satellites: 0.
The main satellites of the planet: 0.
Apparently, the Earth was formed from a gas and dust cloud, like other planets. Particles of gas and dust, colliding, gradually "raised" the planet. The temperature on the surface reached 5000 degrees Celsius. Then the Earth cooled down and became covered with a hard stone crust. But the temperature in the depths is still quite high - 4500 degrees. Rocks in the bowels are molten and pour out to the surface during volcanic eruptions. Only on earth there is water. That's why life exists here. It is located relatively close to the Sun to receive the necessary heat and light, but far enough away so as not to burn out.
Period of revolution around the Sun: 365.3 days. Diameter at the equator: 12756 km.
The period of rotation of the planet (rotation around the axis): 23 hours 56 minutes.
Surface temperature: 22 degrees (average).
Atmosphere: mostly nitrogen and oxygen.
Number of satellites: 1.
The main satellites of the planet: the Moon.
Due to the similarity with the Earth, it was believed that life exists here. But the spacecraft that landed on the surface of Mars found no signs of life. This is the fourth planet in order. 
Period of revolution around the Sun: 687 days.
Diameter of the planet at the equator: 6794 km.
Rotation period (rotation around the axis): 24 hours 37 minutes.
Surface temperature: -23 degrees (average).
Atmosphere of the planet: rarefied, mostly carbon dioxide.
How many satellites: 2.
Main moons in order: Phobos, Deimos.
Jupiter, Saturn, Uranus and Neptune are made up of hydrogen and other gases. Jupiter is more than 10 times larger than Earth in diameter, 300 times in mass and 1300 times in volume. It is more than twice as massive as all the planets in the solar system combined. How much planet Jupiter does it take to become a star? It is necessary to increase its mass by 75 times!
The period of revolution around the Sun: 11 years 314 days. Diameter of the planet at the equator: 143884 km.
Rotation period (turn around the axis): 9 hours 55 minutes.
Surface temperature of the planet: -150 degrees (average).
Number of satellites: 16 (+ rings).
The main satellites of the planets in order: Io, Europa, Ganymede, Callisto.
This is the number 2 largest of the planets in the solar system. Saturn draws attention to itself thanks to a system of rings formed from ice, rocks and dust that orbit the planet. There are three main rings with an outer diameter of 270,000 km, but their thickness is about 30 meters. 
The period of revolution around the Sun: 29 years 168 days.
Diameter of the planet at the equator: 120536 km.
Rotation period (turn around the axis): 10 hours 14 minutes.
Surface temperature: -180 degrees (average).
Atmosphere: mostly hydrogen and helium.
Number of satellites: 18 (+ rings).
Main satellites: Titan.
Unique planet in the solar system. Its peculiarity is that it revolves around the Sun not like everyone else, but "lying on its side." Uranus also has rings, although they are harder to see. In 1986, Voyager 2 flew 64,000 km and had six hours of photography, which it successfully completed.
Orbital period: 84 years 4 days. Diameter at the equator: 51118 km.
The period of rotation of the planet (rotation around the axis): 17 hours 14 minutes.
Surface temperature: -214 degrees (average).
Atmosphere: mostly hydrogen and helium.
How many satellites: 15 (+ rings).
Main satellites: Titania, Oberon.
At the moment, Neptune is considered the last planet in the solar system. Its discovery took place by the method of mathematical calculations, and then they saw it through a telescope. In 1989, Voyager 2 flew by. He took amazing photographs of the blue surface of Neptune and its largest moon, Triton. 
The period of revolution around the Sun: 164 years 292 days.
Diameter at the equator: 50538 km.
Rotation period (turn around the axis): 16 hours 7 minutes.
Surface temperature: -220 degrees (average).
Atmosphere: mostly hydrogen and helium.
Number of satellites: 8.
Main moons: Triton.
On August 24, 2006, Pluto lost planetary status. The International Astronomical Union has decided which celestial body should be considered a planet. Pluto does not meet the requirements of the new formulation and loses its "planetary status", at the same time, Pluto passes into a new quality and becomes the prototype of a separate class of dwarf planets.
How did the planets appear? Approximately 5-6 billion years ago, one of the gas and dust clouds of our large Galaxy (the Milky Way), which has the shape of a disk, began to shrink towards the center, gradually forming the current Sun. Further, according to one of the theories, under the influence of powerful forces of attraction, a large number of dust and gas particles rotating around the Sun began to stick together into balls - forming future planets. According to another theory, the gas and dust cloud immediately broke up into separate clusters of particles, which compressed and condensed, forming the current planets. Now 8 planets revolve around the sun constantly.
