Planets Solar system arranged in order in the following sequence:
1 - Mercury. The smallest true planets in the solar system
2 - Venus. The description of hell was taken from her: the terrible heat, evaporation of sulfur and the eruption of many volcanoes.
3 - Earth. The third planet in order from the Sun, our home.
4 - Mars. The most distant of the terrestrial planets of the solar system.
Then the Main Asteroid Belt is located, where the dwarf planet Ceres and the minor planets Vesta, Pallas, etc. are located.
Further in order are four giant planets:
5 - Jupiter. The largest planet in the solar system.
6 - Saturn with its famous rings.
7 - Uranus. The coldest planet.
8 - Neptune. This is the farthest "real" planet in order from the Sun.
But further curious:
9 - Pluto. A dwarf planet commonly referred to after Neptune. But Pluto's orbit is such that it is sometimes closer to the Sun than Neptune. For example, this was the case from 1979 to 1999.
No, Neptune and Pluto cannot collide :) - their orbits are such that they do not intersect.
The arrangement of the planets of the solar system in order in the photo: 
How many planets are in the solar system
How many planets are in the solar system? This is not an easy answer. For a long time it was believed that there are nine planets in the solar system:
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.
But, on August 24, 2006, Pluto ceased to be considered a planet. This was caused by the discovery of the planet Eris and other small planets of the solar system, in connection with which it was necessary to clarify which celestial bodies can be considered planets.
Several signs of "real" planets have been identified, and it turns out that Pluto does not fully satisfy them.
Therefore, Pluto was transferred to the category of dwarf planets, which include, for example, Ceres - the former asteroid number 1 in the main asteroid belt between Mars and Jupiter.
As a result, when trying to answer the question how many planets are in the solar system, the state of affairs became even more confusing. Because besides "real" dwarf planets have now appeared.
But there are also small planets, which were called large asteroids. For example Vesta, asteroid number 2 in the aforementioned Main Asteroid Belt.
IN recent times the very same Eris, Make-Make, Haumeya and several other small planets of the solar system, data about which is insufficient and it is not clear what to consider them - dwarf or minor planets. Not to mention the fact that some small asteroids are mentioned in the literature as minor planets! For example, the asteroid Icarus, which is only about 1 kilometer in size, is often referred to as a minor planet ...
Which of these bodies should be considered when answering the question "How many planets are in the solar system" ???
In general, "we wanted the best, but it turned out as always."
It is curious that many astronomers and even ordinary people speak out "in defense" of Pluto, continuing to consider it a planet, sometimes arrange small demonstrations and diligently promote this idea on the Web (mainly abroad).
Therefore, when answering the question "how many planets are in the solar system", the easiest way is to say shortly "eight" and not even try to discuss something ... otherwise you will immediately find that there is simply no exact answer :)
The giant planets are the largest planets in the solar system
There are four giant planets in the solar system: Jupiter, Saturn, Uranus and Neptune. Since these planets are located outside the main asteroid belt, they are called the "outer" planets of the solar system.
In size among these giants, two pairs are clearly distinguished.
The largest giant planet is Jupiter. Saturn is quite a bit inferior to him.
And Uranus and Neptune are sharply smaller than the first two planets and they are located farther from the Sun.
Look at the comparative sizes of the giant planets relative to the Sun: 
The giant planets protect the inner planets of the solar system from asteroids.
If these bodies were not in the solar system, our Earth would be hundreds of times more likely to be subject to falling asteroids and comets!
How do the giant planets protect us from the falls of uninvited guests?
You can learn more about the largest planets of the solar system here:
Terrestrial planets
Terrestrial planets are the four planets of the solar system, similar in size and composition: Mercury, Venus, Earth and Mars. 
Since one of them is Earth, all these planets were attributed to the terrestrial group. Their sizes are very similar, and Venus and Earth are generally almost the same. Their temperatures are relatively high due to their proximity to the Sun. All four planets are formed by rocks, while the giant planets are gas and ice worlds.
Mercury is the closest planet to the Sun and the smallest planet in the Solar System.
It is generally accepted that it is very hot on Mercury. Yes, it is, the temperature on the sunny side can reach + 427 ° C. But, on Mercury, there is almost no atmosphere, so on the night side it can be up to -170 ° C. And at the poles, due to the low Sun, a layer of underground permafrost is generally assumed ...
Venus. For a long time it was considered the "sister" of the Earth until Soviet research stations descended on its surface. It turned out to be real hell! The temperature is + 475 ° C, the pressure is almost a hundred atmospheres and the atmosphere is made of poisonous compounds of sulfur and chlorine. To colonize it, you will have to try very hard ...
Mars. The famous red planet. It is the farthest of the terrestrial planets in the solar system.
Like Earth, Mars has moons: Phobos and Deimos
Basically it is a cold, rocky and dry world. Only at the equator at noon can it get warmer up to + 20 ° С, the rest of the time - a fierce frost, up to -153 ° С at the poles.
The planet has no magnetosphere and cosmic radiation mercilessly irradiates the surface.
The atmosphere is very rarefied and not suitable for breathing, nevertheless, its density is enough for sometimes powerful dust storms to happen on Mars.
Despite all the flaws. Mars is the most promising planet for colonization in the solar system. 
Read more about the terrestrial planets in the article The largest planets of the solar system
The largest planet in the solar system
The largest planet in the solar system is Jupiter. It is the fifth planet from the Sun, its orbit is behind the Main Asteroid Belt. Take a look at the size comparison between Jupiter and Earth: 
Jupiter's diameter is 11 times that of Earth, and its mass is 318 times greater. Due to the planet's large size, parts of its atmosphere rotate at different speeds, so Jupiter's belts are clearly visible in the image. At the bottom left is Jupiter's famous Great Red Spot - a huge atmospheric vortex that has been observed for several centuries.
The smallest planet in the solar system
Which planet is the smallest planet in the solar system? This is not such a simple question ...
Today it is generally accepted that the smallest planet in the solar system is Mercury, which we mentioned a little above. But, you already know that until August 24, 2006, Pluto was considered the smallest planet in the solar system.
More attentive readers may recall that Pluto is a dwarf planet. And there are as many as five of them. The smallest dwarf planet is Ceres, with a diameter of about 900 km.
But that's not all ...
There are also the so-called minor planets, the size of which starts from only 50 meters. The 1-kilometer long Icarus and the 490-kilometer Pallas also fall under this definition. It is clear that there are many of them, and it is difficult to choose the smallest one due to the complexity of observations and calculation of sizes. So, when answering the question "what is the name of the smallest planet in the solar system", it all depends on what exactly is meant by the word "planet".
Or tell your friends: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 directional trajectories around the Sun, which is 1000 times heavier than all bodies in the solar system combined. 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 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 other planets that 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. 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 Earth's. The rotation period at the equator is 25.4 days and 34 days at the poles. The mass of the Sun is 2x10, 27 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 (rotation 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. The surface temperature reached 5000 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 depths 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 the 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: rarefied, mainly 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 the diameter of Earth, 300 times its mass and 1300 times its 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? We need to increase its mass 75 times!
The period of revolution around the Sun: 11 years 314 days. Diameter of the planet at the equator: 143884 km
Rotation period (rotation around the axis): 9 hours 55 minutes.
The 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.
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: 120,536 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 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 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 made a decision on 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 shrink towards the center, gradually forming the present Sun. Further, according to one of the theories, under the influence of powerful gravitational forces, 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-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.
In the early 1800s, astronomers knew every major planet in our solar system except Neptune. They also knew Newton's laws of motion and gravity, which could be used to predict the motion of planets. These predictions were compared to their actual recorded movement. But bad luck - Uranus did not go on the predicted course. French astronomer Alexis Bouvard suggested that Uranus was being knocked off course by an invisible planet with gravity.
After Neptune was found in 1846, many astronomers decided to test whether its gravity was sufficient to explain the observed motion of Uranus. But it wasn't enough. Well, there was another invisible planet? The ninth planet has been proposed by a lot of astronomers. The most persistent seeker of this very ninth planet was the American astronomer Percival Lowell, who called it "Planet X".
Lowell built an observatory to find planet X, but never found it. Fourteen years after Lowell's death, an astronomer at his observatory discovered Pluto, but it was not enough to explain the movement of Uranus, so people continued to search for planet X. They did not stop after the Voyager 2 probe passed Neptune in 1989 year. Then astronomers learned that they incorrectly measure the mass of Neptune. And the updated formula for calculating the mass of Neptune explained the motion of Uranus.
Planet between Mars and Jupiter
In the 16th century, Johannes Kepler noticed a large gap between the orbits of Mars and Jupiter. He suggested that there might be a planet, but he did not particularly look for it. After Kepler, many astronomers noticed a pattern in the orbits of the planets. The relative sizes of the orbits, from Mercury to Saturn, are approximately 4, 7, 10, 16, 52 and 100. If you subtract 4 from each number, you get 0, 3, 6, 12, 48, 96. You can note that 6 in two times 3, 12 is twice 6, and 96 is twice 48. But there is a strange factor between 12 and 48.
Astronomers began to wonder if the planet had disappeared between 12 and 48, somewhere around 24 - that is, between Mars and Jupiter. As the German astronomer Johann Elert Bode wrote, “beyond Mars there is empty space at 4 + 24 \u003d 28 segments, where the planet was not yet visible. Would anyone believe that the creator of the universe left this space empty? Of course not". When Uranus was discovered in 1781, its orbit matched the pattern described above. It fit into the law of nature, called Boldé's law or Titius-Bode's law, but the gap between Mars and Jupiter remained.
Hungarian astronomer Baron Franz von Zak was also convinced that Bode's law worked and that there should be a planet between Mars and Jupiter. For several years he looked for her and did not find her. In 1800, he organized several astronomers to conduct a systematic search. One of those astronomers was the Italian Catholic priest Giuseppe Piazzi, who spotted the object in the correct orbit in 1801.
The object, which was named Ceres, was too small for a planet. Ceres was considered an asteroid for a long time, although it was the largest of them in the main asteroid belt. For about half a century it was considered a planet. Today it is classified as a dwarf planet like Pluto. By the way, Bode's law was nevertheless dropped when it was found that the orbit of Neptune did not match the pattern.
Thea
Thea is the name of a hypothetical Mars-sized planet that may have collided with Earth 4.4 billion years ago, breaking apart on impact to form the Moon. English geochemist Alex Holliday is credited with proposing the name of Thea, one of the Titanid sisters from ancient Greek mythology who gave birth to the moon goddess Selena.
It should be noted that the origin and formation of the Moon is still the subject of active scientific research... While Thea's model, known as the giant collision hypothesis, leads the way, it is far from the only one. Perhaps the moon was captured by the gravitational pull of the earth. Perhaps the Earth and the Moon formed at the same time as a couple. Maybe something else. It is also worth noting that the young Earth has suffered from many large bodies, and Thea is just one such body that could have led to the formation of the moon.
Volcano
Uranus was not the only planet whose observed motion was at odds with forecasts. Another planet with this problem was Mercury. The discrepancy was first noticed by the French mathematician Urbain le Verrier, who noted that at the lowest point of Mercury's elliptical orbit (at perihelion), the planet moves around the Sun faster than calculations show. The discrepancy was small, but additional observations of Mercury confirmed the fact of its existence. He suggested that the divergence was caused by an undiscovered planet orbiting within the orbit of Mercury, which he named Vulcan.
And the observation and search for Vulcan began. Some sunspots were mistaken for new planet, other observations of more famous astronomers seemed more plausible. When le Verrier died in 1877, he believed that the existence of Vulcan was or would be confirmed. But in 1915 Einstein's general theory of relativity emerged, which accurately predicted the motion of Mercury. The planet Vulcan was no longer needed, but people continued to search for it. Of course, there is nothing the size of a planet inside the orbit of Mercury, but there could be asteroid-like objects, the so-called "volcanoids".
Phaeton
German astronomer and physicist Heinrich Olbers discovered the second known asteroid Pallas in 1802. He suggested that the two asteroids could be fragments of an ancient medium-sized planet that was destroyed by internal forces or as a result of a collision with a comet. It was suggested that in addition to Ceres and Pallas, there must have been other objects, and two more were soon discovered - Juno in 1804 and Vesta in 1807.
The planet that supposedly disintegrated and formed the main asteroid belt became known as Phaethon after a character in Greek mythology. Phaethon's hypothesis also had problems. For example, the sum of the masses of all asteroids in the main belt is much less than the mass of the planet. Also, asteroids are very different from each other, so how could they have descended from the same ancestor? Today, most planetary scientists believe that asteroids were formed by the gradual clumping of smaller fragments.
Planet V is the name of another hypothetical planet between Mars and Jupiter, but the reasons it might have existed are somewhat different. The story began with apollo missions to the moon... Apollo brought many moon rocks to Earth, some of which were formed by melting rocks. This process occurs when an asteroid hits the moon and generates enough heat to melt the rock. Scientists used radiometric dating to estimate when these stones cooled down and were quite surprised - they were between 3.8 and 4 billion years old.
Apparently, during this time many asteroids or comets fell on the Moon, especially during the so-called "late heavy bombardment". It was "late" because it happened later than the rest of the bombings. Major collisions have occurred throughout the early solar system, but those times are long gone. Hence the question: what happened that temporarily increased the number of asteroids falling on the moon?
About 10 years ago, John Chambers and Jack J. Lissot suggested that a long-lost planet, the so-called Planet V. Scientists suggested that the orbit of Planet V lay between the orbits of Mars and the main asteroid belt until the gravity of the inner planets brought planet V too close to the asteroid belt and they simply did not attack it. The planet, in turn, sent them to the moon. She herself went to the Sun and fell on it. The hypothesis met with a wave of criticism - not everyone agreed that there was a large late bombardment, and if there was, there are other explanations without the need for the existence of planet V.
The fifth gas giant
One of the other explanations for the late heavy bombing is the so-called Nice model, named after the French city in which it was developed. According to Nice's model, Saturn, Uranus, and Neptune - the outer gas giants - began in small orbits surrounded by a cloud of asteroid-like objects. Over time, some of these small objects passed close to the gas giants. These close encounters led to the expansion of the orbits of the gas giants, albeit very slowly. Jupiter's orbit has generally become a little smaller. At some point, the orbits of Jupiter and Saturn entered into resonance, as a result of which Jupiter began to go around the Sun twice, while Saturn goes around it once. This caused chaos.
Everything happened very quickly, within the solar system. The nearly circular orbits of Jupiter and Saturn tightened, and Saturn, Uranus and Neptune had several "close encounters." The cloud of small objects quivered and a late heavy bombardment began. Once it calmed down, the orbits of Jupiter, Saturn, Uranus and Neptune were almost the same as they are now.
The Nice model also predicted other features of the current solar system like trojan asteroids Jupiter, but she did not explain everything. She needed improvement. It was proposed to add a fifth gas giant. Simulations showed that the event that triggered the late heavy bombardment also pushed the gas giant out of the solar system. And this kind of modeling leads to the current appearance of the solar system, so the idea is far from stupid.
The cause of the Kuiper belt
The Kuiper Belt is a donut-shaped cloud of small icy objects orbiting beyond Neptune. Pluto and its moons were the only known Kuiper belt objects for a long time, until in 1992 David Jewitt and Jane Lu announced the discovery of another object in the Kuiper belt.
Since then, astronomers have identified over 1,000 other objects, and the list is constantly growing. Almost all of them are within 48 astronomical units (a.u. is the distance from the Sun to the Earth), which surprised astronomers, who expected to find more objects outside this circle. The fact is that the gravity of Neptune should have cleaned out a number of such objects that were previously closer, but distant objects should have remained independent of Neptune from the early days of the solar system.
An unexpected scattering of objects within 48 AU. That is, it became known as the "Kuiper belt", and no one knows why this happened. Various groups of scientists have suggested that the Kuiper belt was generated by an invisible planet. Patrick Lykavka and Tadashi Mukai revised all these theories and developed their own. Their planet could have spawned the Kuiper belt and many other observable features of the Kuiper belt. Unfortunately, it should be within 100 amu. That is, and this is very far away, so we will not find it soon,.
Cause of Sedna-type orbits
Mike Brown, Chad Trujillo, and David Rabinowitz identified Sedna in 2003. It is a distant object with a very strange orbit around the sun when compared to other objects in the solar system. The closest point to the Sun, in which Sedna was, is at a distance of 76 AU. That is, much further than the Kuiper belt. The orbit of Sedna is completed in 11,400 years.
How did Sedna get into such an orbit? It never approaches the Sun enough to be affected by any of the eight planets. Brown and his colleagues wrote that the orbit of Sedna "could be the result of embarrassment by a planet that has not yet been discovered, the disturbance of an abnormally close encounter with a star, or the formation of the solar system in a cluster of stars." To everyone's surprise, in March 2014, astronomers discovered a second object in a similar orbit, now known as 2012 VP113. This find revived gossip about the possibility of the existence of an invisible planet.
Tyche
A comet's period is the time it takes a comet to go around the sun once. Comets with a long period make it at least 200 years, and possibly longer. Long-period comets come from distant clouds of icy bodies known as Oort clouds, which lie well beyond the Kuiper belt.
In theory, long-period comets should come in equal numbers from all directions. In reality, comets come from one side more often than the other. Why? In 1999, John Matese, Patrick Whitman, and Daniel Whitmire suggested that a large, distant object called Tyche might be the cause. Tyche's mass, according to scientists, should be three masses of Jupiter. The distance to the Sun is about 25,000 AU. e.
However, the WISE Space Telescope recently surveyed the entire sky and provided disappointing results for Matese. On March 7, 2014, NASA reported that WISE is “larger than Jupiter at around 26,000 AU. e. " Apparently, the planet Tyche does not exist.
The solar system is a system of planets, which includes its center - the Sun, as well as other objects of the Cosmos. They revolve around the sun. Until recently, 9 objects of the Cosmos that revolve around the Sun were called "planet". Now scientists have established that outside the solar system there are planets that revolve around the stars.
In 2006, the Union of Astronomers proclaimed that the planets of the solar system are spherical space objects orbiting the sun. On the scale of the solar system, the Earth appears to be extremely small. In addition to the Earth, eight planets revolve around the Sun in their individual orbits. All of them are larger than the Earth. Rotate in the plane of the ecliptic.
Planets in the solar system: types
The location of the terrestrial group in relation to the Sun
The first planet is Mercury, followed by Venus; followed by our Earth and, finally, Mars.
Terrestrial planets do not have many satellites or moons. Of these four planets, only Earth and Mars have satellites.
The planets that belong to the terrestrial group are distinguished by high density, consist of metal or stone. Basically, they are small and rotate on their axis. Their rotation speed is also low.
Gas giants
These are four space objects that are at the greatest distance from the Sun: under number 5 is Jupiter, followed by Saturn, then Uranus and Neptune.
Jupiter and Saturn are both impressive planets, composed of compounds of hydrogen and helium. The density of gas planets is low. They rotate at high speed, have satellites and are surrounded by rings of asteroids.
The "ice giants", which include Uranus and Neptune, are smaller; their atmospheres contain methane and carbon monoxide.
Gas giants have a strong gravitational field, so they can attract many space objects, unlike the terrestrial group.
According to scientists, asteroid rings are the remnants of moons changed by the gravitational field of planets. 
Dwarf planet
Dwarfs are space objects, the size of which does not reach the planet, but exceeds the dimensions of an asteroid. There are a great many such objects in the solar system. They are concentrated in the region of the Kuiper belt. The satellites of the gas giants are dwarf planets that have left their orbit. 
The planets of the solar system: the process of origin
According to the hypothesis of cosmic nebulae, stars are born in clouds of dust and gas, in nebulae.
Due to the force of attraction, substances unite. Under the influence of the concentrated force of gravity, the center of the nebula contracts and stars are formed. Dust and gases are transformed into rings. The rings rotate under the influence of gravity, and planetazimals are formed in the whirlpools, which enlarge and attract cosmetic objects.
Under the influence of the force of gravity, the planetazimals contract and acquire a spherical shape. The spheres can merge and gradually turn into protoplanets. 
There are eight planets within the solar system. They revolve around the sun. Their location is as follows:
The closest "neighbor" of the Sun is Mercury, followed by Venus, followed by the Earth, followed by Mars and Jupiter, Saturn, Uranus and the last, Neptune, are located even further from the Sun.
Space has long attracted people's attention. Astronomers began to study the planets of the solar system in the Middle Ages, examining them in primitive telescopes. But a thorough classification, description of the structural features and movement of celestial bodies became possible only in the 20th century. With the advent of powerful equipment, state-of-the-art observatories and spaceships several previously unknown objects were discovered. Now each student can list all the planets of the solar system in order. Almost all of them were descended by a space probe, and so far man has only been to the moon.
What is the Solar System
The universe is huge and includes many galaxies. Our solar system is part of a galaxy with over 100 billion stars. But there are very few of them that look like the Sun. Basically, they are all red dwarfs, which are both smaller in size and shine less brightly. Scientists have suggested that the solar system was formed after the emergence of the sun. Its huge field of gravity was captured by a gas-dust cloud, from which, as a result of gradual cooling, particles of solid matter were formed. Over time, heavenly bodies were formed from them. It is believed that the Sun is now in the middle of its life path, therefore it, as well as all the celestial bodies dependent on it, will exist for several more billion years. Astronomers have studied the near space for a long time, and anyone knows what planets in the solar system exist. Photos of them taken from space satellites can be found on the pages of all kinds of information resources devoted to this topic. All celestial bodies are held by the strong gravitational field of the Sun, which makes up more than 99% of the volume of the solar system. Large celestial bodies rotate around the star and around its axis in one direction and in one plane, which is called the plane of the ecliptic.
The planets of the solar system in order
In modern astronomy, it is customary to consider celestial bodies starting from the Sun. In the 20th century, a classification was created, which includes 9 planets of the solar system. But recent space exploration and latest discoveries pushed scientists to revise many provisions in astronomy. And in 2006 at the international congress, due to its small size (a dwarf not exceeding three thousand km in diameter), Pluto was excluded from the number of classical planets, and there were eight of them. Now the structure of our solar system has taken on a symmetrical, slender appearance. It includes four terrestrial planets: Mercury, Venus, Earth and Mars, then comes the asteroid belt, followed by four giant planets: Jupiter, Saturn, Uranus and Neptune. On the outskirts of the solar system also passes which scientists called the Kuiper belt. It is in it that Pluto is located. These places are still poorly understood due to their remoteness from the Sun.
Features of the terrestrial planets
What allows these celestial bodies to be attributed to one group? Let's list the main characteristics of the inner planets:
- relatively small size;
- hard surface, high density and similar composition (oxygen, silicon, aluminum, iron, magnesium and other heavy elements);
- presence of atmosphere;
- the same structure: a core of iron with nickel impurities, a mantle consisting of silicates, and a crust of silicate rocks (except for Mercury, it has no crust);
- a small number of satellites - only 3 for four planets;
- rather weak magnetic field.
Features of the giant planets
As for the outer planets, or gas giants, they have the following similar characteristics:
- large sizes and masses;
- they do not have a solid surface and consist of gases, mainly helium and hydrogen (therefore they are also called gas giants);
- liquid core, consisting of metallic hydrogen;
- high rotation speed;
- a strong magnetic field, which explains the unusual nature of many processes taking place on them;
- there are 98 satellites in this group, most of which belong to Jupiter;
- the most characteristic feature of gas giants is the presence of rings. All four planets have them, however, they are not always noticeable.
The first planet in a row - Mercury
It is located closest to the Sun. Therefore, from its surface, the star looks three times larger than from the Earth. This also explains the strong temperature drops: from -180 to +430 degrees. Mercury orbits very quickly. Maybe that's why he got such a name, because in Greek mythology, Mercury is the messenger of the gods. There is practically no atmosphere here, and the sky is always black, but the Sun shines very brightly. However, at the poles there are places where its rays never fall. This phenomenon can be explained by the tilt of the rotation axis. No water was found on the surface. This circumstance, as well as the abnormally high daytime temperature (as well as low nighttime), fully explain the fact that there is no life on the planet.
Venus
If you study the planets of the solar system in order, then Venus is the second in a row. People could observe it in the sky even in antiquity, but since it was shown only in the morning and evening, it was believed that these are 2 different objects. By the way, our Slavic ancestors called her Mertsana. It is the third brightest object in our solar system. Previously, people called it the morning and evening star, because it is best seen before sunrise and sunset. Venus and Earth are very similar in structure, composition, size and gravity. Around its axis, this planet moves very slowly, making a complete revolution in 243.02 Earth days. Of course, conditions on Venus are very different from those on Earth. It is two times closer to the Sun, so it is very hot there. The high temperature is also explained by the fact that thick clouds of sulfuric acid and an atmosphere of carbon dioxide create a greenhouse effect on the planet. In addition, the pressure at the surface is 95 times greater than on Earth. Therefore, the first ship that visited Venus in the 70s of the 20th century lasted no more than an hour there. A feature of the planet is also the fact that it rotates in the opposite direction compared to most planets. More astronomers about this celestial object are not yet known.
The third planet from the Sun
The only place in the solar system, and in the entire universe known to astronomers where life exists, is Earth. In the terrestrial group, it has the largest dimensions. What else are her
- The largest gravity among the terrestrial planets.
- Very strong magnetic field.
- High density.
- She is the only one among all the planets to have a hydrosphere, which contributed to the formation of life.
- It has the largest satellite in comparison with its size, which stabilizes its tilt relative to the Sun and affects natural processes.
The planet Mars
It is one of the smallest planets in our Galaxy. If we consider the planets of the solar system in order, then Mars is the fourth from the Sun. Its atmosphere is very rarefied, and the pressure on the surface is almost 200 times less than on Earth. For the same reason, very strong temperature differences are observed. The planet Mars is little studied, although it has long attracted the attention of people. According to scientists, this is the only celestial body on which life could exist. Indeed, in the past, there was water on the surface of the planet. This conclusion can be made on the basis of the fact that there are large ice caps, and the surface is covered with many furrows, which could have been dried up riverbeds. In addition, there are some minerals on Mars that can only form in the presence of water. Another feature of the fourth planet is the presence of two satellites. Their unusualness is that Phobos gradually slows down its rotation and approaches the planet, while Deimos, on the contrary, moves away.
What is Jupiter famous for
The fifth planet is the largest. The volume of Jupiter would fit 1300 Earths, and its mass is 317 times that of the Earth. Like all gas giants, its structure is hydrogen-helium, reminiscent of the composition of stars. Jupiter is the most interesting planet, which has many characteristic features:
- it is the third brightest celestial body after the Moon and Venus;
- jupiter has the strongest magnetic field of all planets;
- it makes a full revolution around the axis in just 10 Earth hours - faster than other planets;
- an interesting feature of Jupiter is a large red spot - this is how the atmospheric vortex rotating counterclockwise is visible from the Earth;
- like all giant planets, it has rings, although not as bright as those of Saturn;
- this planet has the largest number of satellites. He has 63 of them. The most famous are Europa, where water was found, Ganymede - the largest satellite of the planet Jupiter, as well as Io and Calisto;
- another feature of the planet is that the surface temperature in the shade is higher than in places illuminated by the sun.
Planet saturn
It is the second largest gas giant, also named after an ancient god. It is composed of hydrogen and helium, but traces of methane, ammonia and water have been found on its surface. Scientists have found that Saturn is the most rarefied planet. Its density is less than that of water. This gas giant rotates very quickly - it makes one revolution in 10 Earth hours, as a result of which the planet is flattened from the sides. Huge speeds on Saturn and in the wind - up to 2000 kilometers per hour. This is more than the speed of sound. Saturn has another distinctive feature - it holds 60 satellites in its field of attraction. The largest of them - Titan - is the second largest in the entire solar system. The uniqueness of this object lies in the fact that, while exploring its surface, scientists first discovered a celestial body with conditions similar to those that existed on Earth about 4 billion years ago. But the most important feature of Saturn is the presence of bright rings. They encircle the planet around the equator and reflect more light than itself. Four is the most amazing phenomenon in the solar system. Unusually, the inner rings move faster than the outer rings.
- Uranus
So, we continue to consider the planets of the solar system in order. The seventh planet from the Sun is Uranus. It is the coldest of all - the temperature drops to -224 ° C. In addition, scientists did not find metallic hydrogen in its composition, but found modified ice. Therefore, Uranus belongs to a separate category of ice giants. An amazing feature of this celestial body is that it rotates while lying on its side. The change of seasons on the planet is also unusual: for 42 Earth years, winter reigns there, and the Sun does not appear at all, summer also lasts 42 years, and the Sun does not set at this time. In spring and autumn, the star appears every 9 hours. Like all giant planets, Uranus has rings and many moons. As many as 13 rings revolve around it, but they are not as bright as those of Saturn, and the planet holds only 27 satellites. If we compare Uranus with the Earth, then it is 4 times larger than it, 14 times heavier and is located at a distance of 19 times the path to the luminary from our planet.
Neptune: the invisible planet
After Pluto was excluded from the number of planets, Neptune became the last from the Sun in the system. It is located 30 times farther from the luminary than the Earth, and is not visible from our planet even through a telescope. Scientists discovered it, so to speak, by accident: observing the features of the movement of the planets closest to it and their satellites, they concluded that there must be another large celestial body beyond the orbit of Uranus. After discovery and research, it turned out interesting features of this planet:
- due to the presence of a large amount of methane in the atmosphere, the color of the planet from space appears blue-green;
- neptune's orbit is almost perfectly circular;
- the planet rotates very slowly - it makes one circle in 165 years;
- Neptune 4 times more earth and 17 times heavier, but the force of gravity is almost the same as on our planet;
- the largest of the 13 satellites of this giant is Triton. He is always turned to the planet with one side and slowly approaches it. Based on these signs, scientists suggested that he was captured by the gravity of Neptune.
There are about one hundred billion planets in the entire Milky Way galaxy. So far, scientists cannot study even some of them. But the number of planets in the solar system is known to almost all people on Earth. True, in the 21st century, interest in astronomy has faded a little, but even children know the name of the planets of the solar system.