> Solar system
solar system- planets in order, the Sun, structure, system model, satellites, space missions, asteroids, comets, dwarf planets, interesting facts.
solar system- a place in outer space in which the Sun, planets in order and many other space objects and celestial bodies are located. The solar system is the most precious place we live in, our home.
Our Universe is a huge place where we occupy a tiny corner. But for earthlings, the solar system seems to be the most immense territory, to the far corners of which we are just beginning to approach. And she still hides a ton of mysterious and enigmatic formations. So, despite centuries of study, we only opened the door to the unknown. So what is the solar system? Today we will look at this issue.
Discovery of the solar system
The actual one needs to look up to the sky and you will see our system. But few peoples and cultures understood exactly where we exist and what place we occupy in space. For a long time we thought that our planet is static, located in the center, and other objects rotate around it.
But still, in ancient times, supporters of heliocentrism appeared, whose ideas would inspire Nicolaus Copernicus to create a true model, where the sun was located in the center.
In the 17th century, Galileo, Kepler and Newton were able to prove that the planet Earth revolves around the star Sun. The discovery of gravity helped to understand that other planets follow the same laws of physics.
The revolutionary moment came with the appearance of the first telescope from Galileo Galilei. In 1610, he noticed Jupiter and its moons. This will be followed by the discovery of the rest of the planets.
In the 19th century, three important observations were made that helped to calculate the true nature of the system and its position in space. In 1839, Friedrich Bessel successfully identified the apparent shift in the stellar position. This showed that there is a huge distance between the Sun and the stars.
In 1859, G. Kirchhoff and R. Bunsen used a telescope to carry out spectral analysis of the Sun. It turned out that it consists of the same elements as the Earth. The parallax effect can be seen in the picture below.
As a result, Angelo Secchi was able to match the spectral signature of the Sun with the spectra of other stars. It turned out that they practically converge. Percival Lowell carefully studied the distant corners and orbital paths of the planets. He guessed that there is still an undisclosed object - Planet X. In 1930, in his observatory, Clyde Tombaugh notices Pluto.
In 1992, scientists pushed the boundaries of the system with the discovery of a trans-Neptunian object, 1992 QB1. From this point on, interest in the Kuiper belt begins. This is followed by the finding of Eris and other objects from the team of Michael Brown. All this will lead to the meeting of the IAU and the removal of Pluto from the status of the planet. Below you can study the composition of the solar system in detail by examining all the solar planets in order, the main star the Sun, the asteroid belt between Mars and Jupiter, the Kuiper belt and the Oort Cloud. The solar system also houses the largest planet (Jupiter) and the smallest (Mercury).
The structure and composition of the solar system
Comets are lumps of snow and mud filled with frozen gas, rocks and dust. The closer they come to the Sun, the more they heat up and throw out dust and gas, increasing their brightness.
Dwarf planets rotate around the star, but could not remove foreign objects from orbit. They are inferior in size to standard planets. The most famous representative is Pluto.
The Kuiper Belt is hiding beyond the orbit of Neptune, filled with bodies of ice and formed into a disk. The most famous representatives are Pluto and Eris. Hundreds of ice dwarfs live on its territory. Farthest away is the Oort Cloud. Together they act as a source of arriving comets.
The solar system is only a small part of the Milky Way. Beyond its border is a large-scale space filled with stars. At light speed, it will take 100,000 years to fly over the entire territory. Our galaxy is one of many in the universe.
In the center of the system is the main and only star - the Sun (main sequence G2). The first to follow are 4 terrestrial planets (inner), an asteroid belt, 4 gas giants, the Kuiper belt (30-50 AU) and the spherical Oort Cloud extending over 100,000 AU. to the interstellar medium.
The sun contains 99.86% of the entire systemic mass, and gravity surpasses all forces. Most of the planets are located near the ecliptic and rotate in a single direction (counterclockwise).
Roughly 99% of the planetary mass is represented by gas giants, with Jupiter and Saturn covering over 90%.
The system is unofficially divided into several sections. The inner one includes 4 terrestrial planets and an asteroid belt. Next comes the external system with 4 giants. The zone with trans-Neptune objects (TNO) is distinguished separately. That is, you can easily find the outer line, since it is marked by the large planets of the solar system.
Many planets are considered mini-systems, as they have a group of satellites. Gas giants also have rings - small bands of small particles orbiting the planet. Usually large moons arrive in the gravity block. On the lower layout, you can see a comparison of the sizes of the Sun and the planets of the system.
The sun is 98% hydrogen and helium. Terrestrial planets are endowed with silicate rock, nickel and iron. Giants are composed of gases and ices (water, ammonia, hydrogen sulphide and carbon dioxide).
The bodies of the solar system distant from the star have low temperature indicators. From here, ice giants (Neptune and Uranus) are distinguished, as well as small objects beyond their orbits. Their gases and ices are volatile substances that can condense at a distance of 5 AU. from the sun.
The origin and evolutionary process of the solar system
Our system appeared 4.568 billion years ago as a result of the gravitational collapse of a large-scale molecular cloud, represented by hydrogen, helium and a small amount of heavier elements. This mass collapsed, which led to a rapid rotation.
Most of the mass gathered in the center. The temperature rose. The nebula shrank, increasing acceleration. This resulted in a flattening into a protoplanetary disk with a red-hot protostar.
Due to the high boiling level near the star, only metals and silicates can exist in solid form. As a result, 4 terrestrial planets appeared: Mercury, Venus, Earth and Mars. Metals were scarce, so they were unable to increase their size.
But the giants appeared further, where the material was cool and allowed volatile ice compounds to remain solid. There was much more ice, so the planets dramatically increased their scale, attracting huge amounts of hydrogen and helium into the atmosphere. The remnants could not become planets and settled in the Kuiper belt or moved to the Oort Cloud.
For 50 million years of development, the pressure and density of hydrogen in the protostar launched nuclear fusion. Thus the Sun was born. The wind created the heliosphere and threw gas and dust into space.
The system remains in its usual state for now. But the Sun develops and after 5 billion years completely transforms hydrogen into helium. The core will collapse, releasing a huge energy reserve. The star will enlarge 260 times and become a red giant.
This will lead to the death of Mercury and Venus. Our planet will lose its life because it gets hot. As a result, the outer stellar layers will burst into space, leaving behind a white dwarf, the size of our planet. A planetary nebula will form.
Inner solar system
This is the line with the first 4 planets from the star. They all have similar parameters. It is a rocky type represented by silicates and metals. Closer than giants. They are inferior in density and size, and are also devoid of huge lunar families and rings.
Silicates form the crust and mantle, while metals are part of the cores. All, except for Mercury, have an atmospheric layer that allows the formation of weather conditions. Impact craters and tectonic activity are visible on the surface.
Closest to the star is Mercury... It is also the tiniest planet. The magnetic field reaches only 1% of the earth's, and the thin atmosphere causes the planet to be half-hot (430 ° C) and freeze (-187 ° C).
Venus converges in size to the Earth and has a dense atmospheric layer. But the atmosphere is extremely toxic and works like a greenhouse. It consists of 96% carbon dioxide, along with nitrogen and other impurities. Dense clouds are created from sulfuric acid. There are many canyons on the surface, the deepest of which reaches 6400 km.
Earth best studied because this is our home. It has a rocky surface, covered with mountains and depressions. In the center is a heavy metal core. Water vapor is present in the atmosphere, which smoothes the temperature regime. The moon revolves nearby.
Due to the appearance Mars received the nickname Red Planet. The color is created by oxidation of ferrous materials on the top layer. It is endowed with the largest mountain in the system (Olympus), rising to 21,229 m, as well as the deepest canyon - the Mariner Valley (4000 km). Most of the surface is ancient. There are ice caps at the poles. A thin atmospheric layer hints at water deposits. The core is solid, and there are two satellites next to the planet: Phobos and Deimos.
Outer solar system
Gas giants are located here - large-scale planets with lunar families and rings. Despite their size, only Jupiter and Saturn can be seen without telescopes.
The largest planet in the solar system - Jupiter with a rapid rotational speed (10 hours) and an orbital path of 12 years. The dense atmospheric layer is filled with hydrogen and helium. The core can reach Earth size. There are many satellites, weak rings and the Great Red Spot - a powerful storm that has not been able to calm down for the 4th century.
Saturn- the planet, which is recognized by the chic ring system (7 pieces). The system contains satellites, and the hydrogen and helium atmosphere rotates rapidly (10.7 hours). Spends 29 years to go around the star.
In 1781, William Herschel found Uranus... A day on the giant lasts 17 hours, and the orbital path takes 84 years. Holds a huge amount of water, methane, ammonia, helium and hydrogen. All this is concentrated around the stone core. There is a moon family and rings. In 1986, Voyager 2 flew to him.
Neptune- a distant planet with water, methane, ammonium, hydrogen and helium. There are 6 rings and dozens of satellites. Voyager 2 also flew by in 1989.
Trans-Neptune region of the solar system
Thousands of objects have already been found in the Kuiper belt, but it is believed that up to 100,000 live there with a diameter of more than 100 km. They are extremely small and located at great distances, so the composition is difficult to calculate.
Spectrographs show an ice mixture: hydrocarbons, water ice and ammonia. Initial analysis showed a wide range of colors, from neutral to bright red. This hints at the richness of the composition. Comparison of Pluto and KBO 1993 SC showed that they are extremely different in surface elements.
Water ice was found in 1996 TO66, 38628 Huya and 20,000 Varuna, and crystalline ice was noticed in Kwavara.
The Oort Cloud and Beyond the Solar System
This cloud is believed to extend over 2000-5000 AU. and up to 50,000 AU from the star. The outer edge can be extended by 100,000-200,000 AU. The cloud is divided into two parts: the spherical outer (20000-50000 AU) and the inner (2000-20000 AU).
The outer is inhabited by trillions of bodies with a diameter of a kilometer or more, as well as billions with a width of 20 km. There is no exact information about the mass, but it is believed that Halley's comet is a typical representative. The total mass of the cloud is 3 x 10 25 km (5 lands).
If you focus on comets, then most of the cloud bodies are represented by ethane, water, carbon monoxide, methane, ammonia and hydrogen cyanide. The population is 1-2% asteroids.
Bodies from the Kuiper Belt and Oort Clouds are called trans-Neptunian objects (TNOs), because they are located further than the orbital path of Neptune.
Exploring the Solar System
The dimensions of the solar system still seem immense, but our knowledge has expanded significantly with the sending of probes into outer space. The boom in space exploration began in the middle of the 20th century. Now it can be noted that all the solar planets have at least once been approached by terrestrial vehicles. We have photos, videos, as well as soil and atmosphere analysis (for some).
The first artificial spacecraft was the Soviet Sputnik-1. He was sent into space in 1957. Spent several months in orbit collecting atmospheric and ionospheric data. In 1959, the United States joined with Explorer 6, which took pictures of our planet for the first time.
These devices provided a huge array of information about planetary features. Luna 1 was the first to go to another object. He flew past our satellite in 1959. The Mariner became a successful mission to Venus in 1964, Mariner 4 arrived at Mars in 1965, and the 10th flight in 1974 passed Mercury.
Since the 1970s. the attack on the outer planets begins. In 1973, Pioneer 10 flew past Jupiter, and the next mission visited Saturn in 1979. The real breakthrough was the Voyagers, which flew around large giants and their satellites in the 1980s.
The Kuiper Belt is occupied by New Horizons. In 2015, the device successfully reached Pluto, sending the first close pictures and a lot of information. Now he is racing towards distant TNOs.
But we were eager to land on another planet, so rovers and probes began to send in the 1960s. Luna 10 was the first to enter lunar orbit in 1966. In 1971, Mariner 9 landed near Mars, and Verena 9 orbited the second planet in 1975.
Galileo first whirled near Jupiter in 1995, and the famous Cassini appeared near Saturn in 2004. MESSENGER and Dawn visited Mercury and Vesta in 2011. And the latter still managed to fly around the dwarf planet Ceres in 2015.
The first spacecraft to land on the surface was Luna-2 in 1959. Then there were landings on Venus (1966), Mars (1971), asteroid 433 Eros (2001), Titan and Tempel in 2005.
Now the controlled vehicles have visited only Mars and the Moon. But the first robotic one was Lunokhod 1 in 1970. Spirit (2004), Opportunity (2004) and Curiosity (2012) landed on Mars.
The 20th century was marked by the space race of America and the USSR. For the Soviets, this was the Vostok program. The first mission took place in 1961, when Yuri Gagarin was in orbit. In 1963, the first woman flew, Valentina Tereshkova.
In the United States, they developed the Mercury project, where they also planned to take people into space. The first American to enter orbit was Alan Shepard in 1961. After the end of both programs, countries focused on long-term and short-term flights.
The main goal was the landing of a man on the moon. The USSR was developing a capsule for 2-3 people, and the Gemini tried to create an apparatus for a safe lunar landing. It ended with Apollo 11 successfully landing Neil Armstrong and Buzz Aldrin on the satellite in 1969. In 1972, 5 more landings were made, and all were American.
The next challenge was the creation of a space station and reusable vehicles. The Soviets formed the Salyut and Almaz stations. The first station with a large number of crews was NASA's Skylab. The first settlement was the Soviet Mir, functioning in 1989-1999. In 2001, it was replaced by the International Space Station.
The only reusable spacecraft was Columbia, which completed several orbital flights. 5 shuttles completed 121 missions and retired in 2011. Due to accidents, two shuttles crashed: Challenger (1986) and Columbia (2003).
In 2004, George W. Bush announced his intention to return to the Moon and conquer the Red Planet. This idea was supported by Barack Obama. As a result, now all efforts are spent on the exploration of Mars and plans to create a human colony.
Chapter 6. Solar system (general characteristics)
The solar planetary system is a tiny element of our galaxy called the Milky Way. In the Galaxy there are star systems larger than the solar, but there are also fewer. There are very complex ones, including several stars, connected to each other by gravitational forces and revolving around a common center of mass. I have no doubt that there are planets in those complex multi-star systems.
At the moment, it is believed that the solar system consists of 9 planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto. True, recently Pluto was excluded from the number of planets and was included in the category of special bodies - plutonoids. All planets move in the same direction, in a single plane (with the exception of Pluto), in almost circular orbits. From the center to the outskirts of the solar system (to Pluto) 5.5 light hours. The distance from the Sun to the Earth is 149 million km, which is 107 times the diameter of the Sun.
Hello dear readers! This post will focus on the structure of the solar system. I believe that it is simply necessary to know where our planet is located in the Universe, as well as what else is in our solar system besides the planets ...
The structure of the solar system.
solar system- this is a system of cosmic bodies, which, in addition to the central luminary - the Sun, includes nine large planets, their satellites, many small planets, comets, cosmic dust and small meteoric bodies that move in the sphere of the predominant gravitational action of the Sun.
In the middle of the 16th century, the general structure of the structure of the solar system was revealed by the Polish astronomer Nicolaus Copernicus. He refuted the idea that the Earth is the center of the Universe and substantiated the idea of the motion of the planets around the Sun. This model of the solar system is called heliocentric.
In the 17th century, Kepler discovered the law of planetary motion, and Newton formulated the law of universal attraction. But only after Galileo invented the telescope in 1609, it became possible to study the physical characteristics of the solar system, cosmic bodies.
So Galileo, observing sunspots, first discovered the rotation of the Sun around its axis.
Planet Earth is one of nine celestial bodies (or planets) that orbit the Sun in outer space.
The main part of the solar system is made up of planets, which revolve around the Sun at different speeds in the same direction and almost in the same plane in elliptical orbits and are located at different distances from it.
The planets are arranged in the following order from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto. But Pluto sometimes moves away from the Sun by more than 7 billion km, but due to the huge mass of the Sun, which is almost 750 times the mass of all other planets, it remains in its sphere of attraction.
The largest of the planets Is Jupiter. Its diameter is 11 times the diameter of the Earth and is 142,800 km. The smallest of the planets- This is Pluto, which is only 2,284 km in diameter.
The planets that are closest to the Sun (Mercury, Venus, Earth, Mars) are very different from the next four. They are called terrestrial planets., since, like the Earth, they are composed of solid rocks.
Jupiter, Saturn, Uranus and Neptune, are called Jupiter-type planets, as well as giant planets, and in contrast to them are composed mainly of hydrogen.
There are also other differences between Jupiterian and terrestrial planets."Jupiterians" together with numerous satellites form their own "solar systems".
Saturn has at least 22 moons. And there are only three satellites, including the Moon, in the terrestrial planets. And above all, Jupiter-type planets are surrounded by rings.
Debris from the planets.
Between the orbits of Mars and Jupiter, there is a large gap that could accommodate another planet. This space, in fact, is filled with many small celestial bodies, which are called asteroids, or minor planets.
Ceres is the name of the largest asteroid, with a diameter of about 1000 km. To date, 2,500 asteroids have been discovered, which are much smaller in size than Ceres. These are blocks with diameters that do not exceed several kilometers in size.
Most of the asteroids revolve around the Sun in a wide "asteroid belt" that lies between Mars and Jupiter. The orbits of some asteroids go far beyond this belt, and sometimes approach quite close to the Earth.
These asteroids cannot be seen with the naked eye because they are too small and very distant from us. But other debris - comets, for example - can be visible in the night sky due to their brilliant radiance.
Comets are celestial bodies that are composed of ice, particulate matter and dust. Most of the time, the comet moves in the distant parts of our solar system and is invisible to the human eye, but when it approaches the sun, it begins to glow.
This occurs under the influence of solar heat. The ice partially evaporates and turns into gas, releasing dust particles. The comet becomes visible because the cloud of gas and dust reflects sunlight. The cloud, under the pressure of the solar wind, turns into a waving long tail.
There are also such space objects that can be observed almost every evening. They burn up when they enter the Earth's atmosphere, leaving a narrow luminous trail in the sky - a meteor. These bodies are called meteoric bodies, and their size is no larger than a grain of sand.
Meteorites are large meteoric bodies that reach the earth's surface. Due to the collision of huge meteorites with the Earth, in the distant past, huge craters were formed on its surface. Almost a million tons of meteorite dust is deposited on Earth every year.
The birth of the solar system.
Large gas and dust nebulae, or clouds, are scattered among the stars of our galaxy. In the same cloud, about 4600 million years ago, our solar system was born.This birth took place as a result of the collapse (compression) of this cloud under the action eat the forces of gravity.
Then this cloud began to rotate. And over time, it turned into a rotating disk, the bulk of the substance of which was concentrated in the center. The gravitational collapse continued, the central compaction constantly decreasing and warming up.
The thermonuclear reaction began at a temperature of tens of millions of degrees, and then the central compaction of matter burst into a new star - the Sun.
The planets were formed from dust and gas in the disk. The collision of dust particles, as well as their transformation into large lumps, took place in the inner heated areas. This process is called accretion - increment.
The mutual attraction and collision of all these blocks led to the formation of terrestrial planets.
These planets had a weak gravitational field and were too small to attract the light gases (such as helium and hydrogen) that make up the accretion disk.
The birth of the solar system was a common occurrence - such systems are constantly and everywhere in the universe born. And maybe in one of these systems there is a planet similar to Earth, on which intelligent life exists ...
So we examined the structure of the solar system, and now we can arm ourselves with knowledge for their further application in practice 😉
solar system- these are 8 planets and more than 63 of their satellites, which are opening 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 bodies in the solar system put together. The center of the solar system is the Sun - the star around which the planets revolve in orbits. They do not emit heat and do not glow, but only reflect the light of the Sun. There are now 8 officially recognized planets in the solar system. Briefly, in order of distance from the sun, we list them all. And now there are a few definitions.
Planet Is a celestial body that must satisfy four conditions:
1.the body must revolve around the star (for example, around the sun);
2. the body must have sufficient gravity to be spherical or close to it;
3. the body should not have other large bodies near its orbit;
4.the body shouldn't be a star
Satellites of the planets. The solar system also includes the Moon and 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. The smallest satellite of Jupiter - Leda - is only 10 km across.
Is a star, without which life on Earth could not exist. She gives us energy and warmth. According to the classification of stars, the Sun is a yellow dwarf. Age 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, about 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. In terms of chemical composition, the Sun consists of 75% hydrogen, and of the other 25% of the elements, most of all helium. Now, in order, let's figure out how many planets revolve around the sun, in the solar system and the characteristics of the planets.
The four inner planets (closest 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.
The period of revolution around the Sun: 87.97 days. Diameter at the equator: 4878 km.
Rotation period (revolution around the axis): 58 days.
Surface temperature: 350 during the day and -170 at night.
Atmosphere: very thin, helium.
How many satellites: 0.
The main satellites of the planet: 0.
More like Earth in size and brightness. Observing her is difficult because of the clouds that envelop her. The surface is a hot rocky desert. 
The period of revolution around the Sun: 224.7 days.
Diameter at the equator: 12104 km.
Rotation period (revolution around the axis): 243 days.
Surface temperature: 480 degrees (average).
Atmosphere: dense, mainly 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 "grew" the planet. Surface temperatures reached 5,000 degrees Celsius. Then the Earth cooled down and was covered with hard stone crust. But the temperature in the bowels is still quite high - 4500 degrees. Rocks in the bowels are melted and, during volcanic eruptions, are poured onto the surface. Only on earth there is water. That is why life exists here. It is located relatively close to the Sun in order to receive the necessary heat and light, but far enough so as not to burn out.
The period of revolution around the Sun: 365.3 days. Diameter at equator: 12756 km.
The period of the planet's rotation (revolution around the axis): 23 hours 56 minutes.
Surface temperature: 22 degrees (average).
Atmosphere: Mainly nitrogen and oxygen.
Number of satellites: 1.
The main satellites of the planet: the Moon.
Due to the resemblance to Earth, it was believed that life exists here. But the spacecraft that landed on the surface of Mars showed no signs of life. This is the fourth planet in order. 
The period of revolution around the Sun: 687 days.
Diameter of the planet at the equator: 6794 km
Rotation period (revolution around the axis): 24 hours 37 minutes.
Surface temperature: –23 degrees (average).
Atmosphere of the planet: thin, mostly carbon dioxide.
How many satellites: 2.
The main satellites in order: Phobos, Deimos.
Jupiter, Saturn, Uranus and Neptune are composed 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 long does it take for the planet Jupiter 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 (revolution around the axis): 9 hours 55 minutes.
The planet's surface temperature is –150 degrees (average).
Number of satellites: 16 (+ rings).
The main satellites of the planets in order: Io, Europa, Ganymede, Callisto.
It is the number 2 largest planet in the solar system. Saturn is eye-catching thanks to its ring system made of ice, rocks and dust that orbits 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 (revolution around the axis): 10 hours 14 minutes.
Surface temperature: -180 degrees (average).
Atmosphere: Mainly hydrogen and helium.
Number of satellites: 18 (+ rings).
Main satellites: Titan.
Unique planet in the solar system. Its peculiarity is that it does not revolve around the Sun like everyone else, but "lying on its side". Uranus also has rings, although they are more difficult to see. In 1986, Voyager-2 flew at a distance of 64,000 km, he had six hours of photography, which he successfully implemented.
Circulation period: 84 years 4 days. Diameter at the equator: 51,118 km.
The period of the planet's rotation (revolution around the axis): 17 hours 14 minutes.
Surface temperature: –214 degrees (average).
Atmosphere: Mainly 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 means of mathematical calculations, and then they saw it through a telescope. In 1989, Voyager 2 flew by. He took striking 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.
Period of rotation (revolution around the axis): 16 hours 7 minutes.
Surface temperature: –220 degrees (average).
Atmosphere: Mainly hydrogen and helium.
Number of satellites: 8.
Main satellites: Triton.
On August 24, 2006, Pluto lost its 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 the planets appeared. Approximately 5-6 billion years ago, one of the disk-shaped gas and dust clouds of our large Galaxy (Milky Way) began to collapse towards the center, gradually forming the present Sun. Further, according to one of the theories, under the influence of powerful forces of attraction, a large number of dust and gas particles revolving around the Sun began to stick together into balls - forming future planets. According to another theory, the gas-dust cloud immediately disintegrated into separate clusters of particles, which were compressed and compressed, forming the current planets. Now 8 planets revolve around the Sun constantly.
