Planets of the solar system - a bit of history
Previously, a planet was considered to be any body that revolves around a star, glows with light reflected from it, and has a size larger than that of asteroids.
Also in Ancient Greece mentioned seven luminous bodies that move across the sky against the background of fixed stars. These cosmic bodies were: Sun, Mercury, Venus, Moon, Mars, Jupiter and Saturn. Earth was not included in this list, since the ancient Greeks considered the Earth to be the center of all things.
And only in the XVI century Nicolaus Copernicus in his scientific work titled "On the Revolution of the Celestial Spheres" came to the conclusion that not the Earth, but the Sun should be in the center of the planetary system. Therefore, the Sun and the Moon were removed from the list, and the Earth was added to it. And after the advent of telescopes, Uranus and Neptune were added, in 1781 and 1846, respectively.
Pluto was considered the last discovered planet in the solar system from 1930 until recently.
And now, almost 400 years after Galileo Galilei created the world's first telescope for observing stars, astronomers have come to the next definition of a planet.
Planet- this is a celestial body that must satisfy four conditions:
the body must revolve around a star (for example, around the Sun);
the body must have sufficient gravity to be spherical or close to it;
the body should not have other large bodies near its orbit;
the body does not have to be a star.
In turn, the polar star is a cosmic body that emits light and is a powerful source of energy. This is explained, firstly, by the thermonuclear reactions occurring in it, and secondly, by the processes of gravitational compression, as a result of which a huge amount of energy is released.
Planets of the solar system today
solar system- This is a planetary system that consists of a central star - the Sun - and all natural space objects revolving around it.
So, today the solar system consists of of the eight planets: four inner, so-called terrestrial planets, and four outer planets, called gas giants.
The terrestrial planets include Earth, Mercury, Venus and Mars. All of them consist mainly of silicates and metals.
The outer planets are Jupiter, Saturn, Uranus and Neptune. The composition of gas giants consists mainly of hydrogen and helium.
The sizes of the planets in the solar system vary both within groups and between groups. So, the gas giants are much larger and more massive than the terrestrial planets.
Closest to the Sun is Mercury, then as far as the distance: Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
It would be wrong to consider the characteristics of the planets of the solar system without paying attention to its main component: the Sun itself. Therefore, we will start with it. 
The sun planet is a star that gave rise to all life in the solar system. Planets, dwarf planets and their satellites, asteroids, comets, meteorites and cosmic dust revolve around it.
The Sun arose about 5 billion years ago, is a spherical, hot plasma ball and has a mass that is more than 300 thousand times the mass of the Earth. The surface temperature is over 5,000 degrees Kelvin, and the core temperature is over 13 million K.
The sun is one of the largest and most bright stars in our galaxy, which is called the galaxy Milky Way. The Sun is located at a distance of about 26 thousand light years from the center of the Galaxy and makes a complete revolution around it in about 230-250 million years! For comparison, the Earth makes a complete revolution around the Sun in 1 year.
Mercury planet
Mercury is the smallest planet in the system and is closest to the Sun. Mercury has no satellites.
The surface of the planet is covered with craters that arose about 3.5 billion years ago as a result of massive bombardment by meteorites. The diameter of the craters can range from a few meters to more than 1000 km.
The atmosphere of Mercury is very rarefied, consists mainly of helium and swells solar wind. Since the planet is located very close to the Sun and does not have an atmosphere that would keep warm at night, the temperature on the surface ranges from -180 to +440 degrees Celsius.
By earthly standards, Mercury makes a complete revolution around the Sun in 88 days. On the other hand, a Mercury day is equal to 176 Earth days.
Venus planet
Venus is the second closest planet to the Sun in the solar system. Venus is only slightly smaller than Earth, which is why it is sometimes referred to as "Earth's sister". Has no satellites.
The atmosphere is made up of carbon dioxide with impurities of nitrogen and oxygen. The air pressure on the planet is more than 90 atmospheres, which is 35 times more than the earth.
carbon dioxide and, consequently, Greenhouse effect, dense atmosphere, and proximity to the Sun allow Venus to bear the title of "hottest planet". The temperature on its surface can reach 460°C.
Venus is one of the brightest objects in the Earth's sky after the Sun and Moon.
Planet Earth 
Earth is the only known planet in the universe today that has life on it. The Earth has the largest size, mass and density among the so-called inner planets of the solar system.
The age of the Earth is about 4.5 billion years, and life appeared on the planet about 3.5 billion years ago. The Moon is a natural satellite, the largest of the satellites of the terrestrial planets.
The atmosphere of the Earth is fundamentally different from the atmospheres of other planets due to the presence of life. Most of the atmosphere is nitrogen, but it also contains oxygen, argon, carbon dioxide and water vapor. The ozone layer and the Earth's magnetic field, in turn, weaken the life-threatening effects of solar and cosmic radiation.
Due to the carbon dioxide contained in the atmosphere, the greenhouse effect also takes place on Earth. It does not appear as strongly as on Venus, but without it, the air temperature would be approximately 40 ° C lower. Without the atmosphere, temperature fluctuations would be very significant: according to scientists, from -100 ° C at night to + 160 ° C during the day.
About 71% of the Earth's surface is occupied by the oceans, the remaining 29% are continents and islands.
mars planet
Mars is the seventh largest planet in the solar system. The "Red Planet", as it is also called due to the presence of a large amount of iron oxide in the soil. Mars has two moons: Deimos and Phobos.
The atmosphere of Mars is highly rarefied, and the distance to the Sun is almost one and a half times greater than that of the Earth. Therefore, the average annual temperature on the planet is -60 ° C, and temperature drops in some places reach 40 degrees during the day.
Distinctive features of the surface of Mars are impact craters and volcanoes, valleys and deserts, ice polar caps like those on Earth. The tallest mountain in the solar system is located on Mars: dormant volcano Olympus, whose height is 27 km! As well as the largest canyon: the Marinera Valley, the depth of which reaches 11 km, and the length is 4500 km 
Jupiter planet
Jupiter is the largest planet in the solar system. It is 318 times heavier than the Earth, and almost 2.5 times more massive than all the planets in our system combined. In its composition, Jupiter resembles the Sun - it consists mainly of helium and hydrogen - and radiates a huge amount of heat, equal to 4 * 1017 watts. However, in order to become a star like the Sun, Jupiter must be another 70-80 times heavier.
Jupiter has as many as 63 satellites, of which it makes sense to list only the largest ones - Callisto, Ganymede, Io and Europa. Ganymede is the largest moon in the solar system, larger than even Mercury.
Due to certain processes in inner atmosphere Jupiter, many vortex structures appear in its outer atmosphere, for example, stripes of clouds of brown-red hues, as well as the Great Red Spot, a giant storm known since the 17th century.
saturn planet
Saturn is the second largest planet in the solar system. The hallmark of Saturn is, of course, its ring system, which consists mainly of ice particles. different size(from tenths of a millimeter to several meters), as well as rocks and dust.
Saturn has 62 moons, the largest of which are Titan and Enceladus.
In its composition, Saturn resembles Jupiter, but in density it is inferior even to ordinary water.
The outer atmosphere of the planet looks calm and homogeneous, which is explained by a very dense layer of fog. However, the wind speed in some places can reach 1800 km/h.
Uranus planet
Uranus is the first planet to be discovered with a telescope, and also the only planet in the solar system that wraps around the sun, "lying on its side."
Uranus has 27 moons named after Shakespearean heroes. The largest of them are Oberon, Titania and Umbriel.
The composition of the planet differs from the gas giants in the presence of a large number of high-temperature modifications of ice. Therefore, along with Neptune, scientists have identified Uranus in the category of "ice giants". And if Venus has the title of "hottest planet" in the solar system, then Uranus is the coldest planet with a minimum temperature of about -224 ° C.
Neptune planet
Neptune is the most distant planet from the center of the solar system. The history of its discovery is interesting: before observing the planet through a telescope, scientists calculated its position in the sky using mathematical calculations. This happened after the discovery of inexplicable changes in the movement of Uranus in its own orbit.
To date, 13 satellites of Neptune are known to science. The largest of them - Triton - is the only satellite that moves in the opposite direction to the rotation of the planet. The fastest winds in the solar system also blow against the rotation of the planet: their speed reaches 2200 km/h.
The composition of Neptune is very similar to Uranus, therefore it is the second "ice giant". However, like Jupiter and Saturn, Neptune has internal source heat and radiates 2.5 times more energy than it receives from the sun.
The planet's blue color comes from traces of methane in the outer atmosphere.
Conclusion
Pluto, unfortunately, did not have time to get into our parade of planets in the solar system. But it is absolutely not worth worrying about this, because all the planets remain in their places, despite changes in scientific views and concepts.
So, we answered the question of how many planets are there in the solar system. There are only 8 .
The sun and the planets revolving around it, together with other cosmic bodies (meteorites, asteroids, comets) make up the solar system.
Some planets in this system are located closer to the star, some are further away, but all cosmic bodies in it move in their own directions around the Sun, whose mass is a thousand times greater than the mass of all other celestial bodies in the solar system.
There are eight planets in the solar system, and they are divided into two categories - internal and external.
inner planets
The closest planets to the Sun - Mercury, Venus, Earth and Mars - are called internal. All of them are characterized by a hard surface and have relatively small size. Mercury freezes at night and is burned by the sun's rays during the day, because it is closest to the Sun.
Mercury moves faster than all other planets in the solar system. Venus is very similar in size and brightness to Earth, but its surface is a rocky desert. Venus is shrouded in clouds, so observation of this planet is difficult.
Earth is the only planet in the system that has life. Our planet is located on optimal distance from the Sun, so as not to burn out in its rays and not to freeze without a sufficient amount of heat and light. Scientists believe that the Earth, like other planets, was formed from a gas and dust cloud. 
After the temperature on its surface reached five thousand degrees, the planet began to cool, and as a result was covered with solid rock - the earth's crust. But closer to the core of the Earth, the temperature is still extremely high, and from time to time hot lava erupts from the deep layers of the earth's interior in the form of volcanic eruptions. Earth is the only planet in the solar system where there is water.
For a very long time, representatives of the world of science believed that life could be discovered and, because it is located close to the Earth and is similar to it in many ways. But to date, spacecraft sent to Mars have not confirmed this hypothesis.
giant planets
The four outer planets - Jupiter, Saturn, Uranus, Neptune - are many times greater in size and mass than the inner planets. For example, the difference between the Earth and Jupiter is ten times in diameter, three hundred times in mass and 1300 times in volume - not in favor of the Earth. The outer planets of the solar system are made up of hydrogen and other gases.
Jupiter weighs twice as much as all the other planets in the solar system combined. Saturn is the second largest planet in the system. It is recognizable in the drawings due to the rings encircling the planet - these are the “rings of Saturn”, consisting of dust, stones and ice flying around it. The three main rings of Saturn are about 30 meters thick and 270,000 kilometers in diameter. 
Scientists call the planet Uranus unique - it revolves around the Sun, as if lying on its side. Uranus also has rings, but even astronomers cannot see them without special equipment. The rings around Uranus became known after the Voyager 2 spacecraft flew over this planet in 1986 at a distance of 64 thousand kilometers and was able to take photographs.
The farthest from the Sun is Neptune, the location of which was first deduced using mathematical calculations, and only after that they were able to see the planet through a telescope. The same Voyager 2 took pictures of Neptune and its moon Triton in 1989.
former planet
Previously, there were nine planets in the solar system, but the situation changed in 2006: it was then that Pluto lost its status as a planet and moved into the category of “dwarf planets”.
This happened because the International Astronomical Union revised the parameters that the planets must meet. The main conditions for compliance with this status were: rotation in orbit around the Sun; massiveness, sufficient to take a spherical shape under the influence of its own gravity; clean neighborhoods of the orbit of a celestial body.
The last condition means that the planets should serve as a gravitational dominant, there should not be other bodies of comparable size nearby, except for the satellites of this planet or other celestial bodies that are under its gravitational influence. 
It turned out that Pluto does not satisfy the third condition: its mass is only 0.07 of the mass of all objects in its orbit. That is, it was not a gravitational dominant, and therefore lost its planetary status.
As a result, in September 2006, Pluto and Eris, as well as the satellite of Eris - Dysnomia - were included in the catalog of minor planets.
Until recently, astronomers believed that such a concept as a planet refers exclusively to the solar system. Everything that is outside it is unexplored cosmic bodies, most often stars of very large scales. But, as it turned out later, the planets, like peas, are scattered throughout the universe. They differ in their geological and chemical composition, may or may not have an atmosphere, and it all depends on the interaction with the nearest star. The arrangement of the planets in our solar system is unique. It is this factor that is fundamental for the conditions that have formed on each individual space object.
Our space house and its features
In the center of the solar system is the star of the same name, which is included in the category of yellow dwarfs. Its magnetic field is enough to hold nine planets of various sizes around its axis. Among them there are dwarf stony cosmic bodies, immense gas giants that reach almost the parameters of the star itself, and objects of the "middle" class, which include the Earth. The positions of the planets in the solar system do not occur in ascending or descending order. We can say that with respect to the parameters of each individual astronomical body, their arrangement is chaotic, that is, the large alternates with the small.
SS structure
To consider the location of the planets in our system, it is necessary to take the Sun as a reference point. This star is in the center of the SS, and it is her magnetic fields correct the orbits and movements of all surrounding space bodies. Nine planets revolve around the sun, as well as an asteroid ring that lies between Mars and Jupiter, and the Kuiper Belt, located outside of Pluto. In these intervals, individual dwarf planets are also distinguished, which are sometimes attributed to the main units of the system. Other astronomers believe that all these objects are nothing more than large asteroids, on which, under no circumstances, life can arise. They attribute Pluto itself to this category, leaving only 8 planetary units in our system.
The order of the planets
So, we will list all the planets, starting with the one closest to the Sun. In the first place are Mercury, Venus, then Earth and Mars. After the Red Planet, a ring of asteroids passes, behind which a parade of giants consisting of gases begins. These are Jupiter, Saturn, Uranus and Neptune. The list is completed by the dwarf and icy Pluto, with its no less cold and black satellite Charon. As we said above, several more dwarf space units are distinguished in the system. The location of dwarf planets in this category coincides with the Kuiper belts and asteroids. Ceres is in an asteroid ring. Makemake, Haumea and Eris are in the Kuiper belt.
terrestrial planets
This category includes cosmic bodies, which in their composition and parameters have much in common with our home planet. Their bowels are also filled with metals and stone, either a full-fledged atmosphere is formed around the surface, or a haze that resembles it. The location of the terrestrial planets is easy to remember, because these are the first four objects that are directly next to the Sun - Mercury, Venus, Earth and Mars. characteristic features are small sizes, as well as a long period of rotation around its axis. Also, of all the terrestrial planets, only the Earth itself and Mars have satellites.
Giants made of gases and hot metals
The location of the planets of the solar system, which are called gas giants, is the most distant from the main star. They are located behind the asteroid ring and stretch almost to the Kuiper belt. There are four giants in total - Jupiter, Saturn, Uranus and Neptune. Each of these planets consists of hydrogen and helium, and in the region of the core there are red-hot liquid state metals. All four giants are characterized by an incredibly strong gravitational field. Due to this, they attract numerous satellites to themselves, which form almost entire asteroid systems around them. SS gas balls rotate very quickly, therefore whirlwinds and hurricanes often occur on them. But, despite all these similarities, it is worth remembering that each of the giants is unique in its composition, size, and gravity.
dwarf planets
Since we have already considered in detail the location of the planets from the Sun, we know that Pluto is the farthest, and its orbit is the most gigantic in the SS. It is he who is the most important representative of dwarfs, and only he from this group is the most studied. Dwarfs are those cosmic bodies that are too small for planets, but also large for asteroids. Their structure can be comparable to Mars or Earth, or it can be just rocky, like any asteroid. Above, we have listed the brightest representatives of this group - these are Ceres, Eris, Makemake, Haumea. In fact, dwarfs are found not only in the two SS asteroid belts. Often they are called satellites of gas giants, which were attracted to them due to the huge
What is the solar system in which we live? The answer will be as follows: this is our central star, the Sun and all the cosmic bodies that revolve around it. These are large and small planets, as well as their satellites, comets, asteroids, gases and cosmic dust.
The name of the solar system was given by the name of its star. In a broad sense, "solar" is often understood as any star system.
How did the solar system originate?
According to scientists, the solar system was formed from a giant interstellar cloud of dust and gases due to gravitational collapse in a separate part of it. As a result, a protostar formed in the center, then turned into a star - the Sun, and a huge protoplanetary disk, from which all the components of the solar system listed above were subsequently formed. The process is believed to have begun about 4.6 billion years ago. This hypothesis has been called the nebular one. Thanks to Emmanuel Swedenborg, Immanuel Kant and Pierre-Simon Laplace, who proposed it back in the 18th century, it eventually became generally accepted, but over the course of many decades it was refined, new data was introduced into it, taking into account knowledge modern sciences. So, it is assumed that due to the increase and intensification of collisions of particles with each other, the temperature of the object grew, and after it reached a value of several thousand kelvins, the protostar acquired a glow. When temperature indicator reached millions of kelvins, in the center of the future Sun, a thermonuclear fusion reaction began - the conversion of hydrogen into helium. It turned into a star.
The sun and its features
Our luminary scientists refer to the type of yellow dwarfs (G2V) according to the spectral classification. This is the closest star to us, its light reaches the surface of the planet in just 8.31 seconds. From the Earth it seems that the radiation has yellow tint, although in reality it is almost white.
The main components of our luminary are helium and hydrogen. In addition, thanks to spectral analysis, it was found that iron, neon, chromium, calcium, carbon, magnesium, sulfur, silicon, and nitrogen are present on the Sun. Thanks to the thermonuclear reaction continuously going on in its depths, all life on Earth receives the necessary energy. sunlight- an integral part of photosynthesis, as a result of which oxygen is formed. Without sun rays it would be impossible, therefore, an atmosphere suitable for a protein form of life could not form.
Mercury
This is the closest planet to our star. Together with the Earth, Venus and Mars, it belongs to the planets of the so-called terrestrial group. Mercury got its name because of the high speed of movement, which, according to myths, distinguished the fleet-footed ancient god. The Mercury year is 88 days.
The planet is small, its radius is only 2439.7, and it is smaller in size than some of the large satellites of the giant planets, Ganymede and Titan. However, unlike them, Mercury is quite heavy (3.3 10 23 kg), and its density is only slightly behind the earth's. This is due to the presence of a heavy dense core of iron in the planet.
There is no change of seasons on the planet. Its desert surface resembles that of the Moon. It is also covered with craters, but even less habitable. So, on the day side of Mercury the temperature reaches +510 °C, and on the night side -210 °C. These are the most sharp drops throughout the solar system. The planet's atmosphere is very thin and rarefied.
Venus
This planet, named after the ancient Greek goddess of love, is more similar to the Earth than others in the solar system in terms of its physical parameters - mass, density, size, volume. For a long time they were considered twin planets, but over time it turned out that their differences are huge. So, Venus has no satellites at all. Its atmosphere consists of almost 98% carbon dioxide, and the pressure on the planet's surface exceeds the earth's by 92 times! Clouds above the surface of the planet, consisting of sulfuric acid vapor, never dissipate, and the temperature here reaches +434 °C. On the planet go acid rain, thunderstorms are raging. There is high volcanic activity here. Life, in our understanding, cannot exist on Venus; moreover, descent spacecraft cannot withstand such an atmosphere for a long time.
This planet is clearly visible in the night sky. This is the third brightest object for an earthly observer, it shines with white light and surpasses all stars in brightness. The distance to the Sun is 108 million km. It completes a revolution around the Sun in 224 Earth days, and around its own axis - in 243.
Earth and Mars
These are the last planets of the so-called terrestrial group, the representatives of which are characterized by the presence of a solid surface. In their structure, the core, mantle and crust are distinguished (only Mercury does not have it).
Mars has a mass equal to 10% of the mass of the Earth, which, in turn, is 5.9726 10 24 kg. Its diameter is 6780 km, almost half that of our planet. Mars is the seventh largest planet in the solar system. Unlike Earth, which has 71% of its surface covered by oceans, Mars is completely dry land. Water has been preserved under the surface of the planet in the form of a massive ice sheet. Its surface has a reddish tint due to high content iron oxide in the form of maghemite.
The atmosphere of Mars is very rarefied, and the pressure on the surface of the planet is 160 times less than we are used to. On the surface of the planet there are impact craters, volcanoes, depressions, deserts and valleys, and at the poles there are ice caps, just like on Earth.
The Martian day is slightly longer than the Earth day, and the year is 668.6 days. Unlike the Earth, which has one moon, the planet has two satellites. irregular shape- Phobos and Deimos. Both of them, like the Moon to the Earth, are constantly turned to Mars by the same side. Phobos is gradually approaching the surface of its planet, moving in a spiral, and is likely to eventually fall on it or fall apart. Deimos, on the other hand, is gradually moving away from Mars and may leave its orbit in the distant future.
Between the orbits of Mars and the next planet, Jupiter, there is an asteroid belt consisting of small celestial bodies.
Jupiter and Saturn
What planet is the largest? There are four gas giants in the solar system: Jupiter, Saturn, Uranus and Neptune. Largest dimensions of which Jupiter has. Its atmosphere, like that of the Sun, is predominantly hydrogen. The fifth planet, named after the god of thunder, has an average radius of 69,911 km and a mass exceeding that of the earth by 318 times. The planet's magnetic field is 12 times stronger than Earth's. Its surface is hidden under opaque clouds. So far, scientists find it difficult to say exactly what processes can occur under this dense veil. It is assumed that on the surface of Jupiter there is a boiling hydrogen ocean. Astronomers consider this planet a "failed star" due to some similarity in their parameters.
Jupiter has 39 satellites, 4 of which - Io, Europa, Ganymede and Callisto - were discovered by Galileo.
Saturn is somewhat smaller than Jupiter, it is the second largest among the planets. This is the sixth, next planet, also consisting of hydrogen with helium impurities, a small amount of ammonia, methane, water. Hurricanes rage here, the speed of which can reach 1800 km / h! Saturn's magnetic field is not as strong as Jupiter's, but stronger than Earth's. Both Jupiter and Saturn are somewhat flattened at the poles due to rotation. Saturn is 95 times heavier than earth, but its density is less than that of water. It is the least dense celestial body in our system.
A year on Saturn lasts 29.4 Earth days, a day is 10 hours 42 minutes. (Jupiter has a year - 11.86 Earth, a day - 9 hours 56 minutes). It has a system of rings made up of solid particles different size. Presumably, these may be the remains of the collapsed satellite of the planet. In total, Saturn has 62 satellites.
Uranus and Neptune are the last planets
The seventh planet of the solar system is Uranus. It is 2.9 billion km away from the Sun. Uranus is the third largest among the planets of the solar system (average radius - 25,362 km) and the fourth largest (exceeds the earth by 14.6 times). A year here lasts 84 Earth hours, a day - 17.5 hours. In the atmosphere of this planet, in addition to hydrogen and helium, a significant volume is occupied by methane. Therefore, for an earthly observer, Uranus has a pale blue color.
Uranus is the coldest planet in the solar system. The temperature of its atmosphere is unique: -224 °C. Why is Uranus more low temperature than on planets that are farther from the Sun, scientists do not know.
This planet has 27 moons. Uranus has thin, flat rings.
Neptune, the eighth planet from the Sun, ranks fourth in size (average radius - 24,622 km) and third in mass (17 Earth). For a gas giant, it is relatively small (only four times the size of the Earth). Its atmosphere is also mainly composed of hydrogen, helium and methane. Gas clouds in its upper layers move at a record speed, the highest in the solar system - 2000 km / h! Some scientists believe that under the surface of the planet, under the thickness of frozen gases and water, hidden, in turn, by the atmosphere, a solid stone core can hide.
These two planets are close in composition, and therefore they are sometimes referred to as separate category- ice giants.
Minor planets
Small planets are called celestial bodies, which also move around the Sun in their own orbits, but differ from other planets in insignificant sizes. Previously, only asteroids were included in them, but more recently, namely, since 2006, Pluto, which was previously included in the list of planets in the solar system and was the last, tenth, belongs to them. This is due to changes in terminology. Thus, the minor planets now include not only asteroids, but also dwarf planets - Eris, Ceres, Makemake. They were named plutoids after Pluto. The orbits of all known dwarf planets are beyond the orbit of Neptune, in the so-called Kuiper belt, which is much wider and more massive than the asteroid belt. Although their nature, as scientists believe, is the same: it is the "unused" material left after the formation of the solar system. Some scientists have suggested that the asteroid belt is the debris of the ninth planet, Phaeton, which died as a result of a global catastrophe.
Pluto is known to be composed primarily of ice and solid rock. The main component of its ice sheet is nitrogen. Its poles are covered with eternal snows.
This is the order of the planets of the solar system, according to modern ideas.
Parade of planets. Types of parades
This is a very interesting phenomenon for those who are interested in astronomy. It is customary to call a parade of planets such a position in the solar system, when some of them, continuously moving along their orbits, for a short time occupy a certain position for an earthly observer, as if lining up along one line.
The visible parade of planets in astronomy is a special position of the five brightest planets of the solar system for people who see them from Earth - Mercury, Venus, Mars, as well as two giants - Jupiter and Saturn. At this time, the distance between them is relatively small and they are clearly visible in a small sector of the sky.
There are two types of parades. A big one is its appearance when five celestial bodies line up in one line. Small - when there are only four of them. These phenomena can be visible or invisible from different areas. the globe. At the same time, a large parade is quite rare - once every few decades. The small one can be observed once every few years, and the so-called mini-parade, in which only three planets participate, is almost every year.
Interesting facts about our planetary system
Venus, the only one of all the major planets in the solar system, rotates around its axis in the opposite direction to its rotation around the Sun.
The highest mountain on the major planets of the solar system is Olympus (21.2 km, diameter - 540 km), an extinct volcano on Mars. Not so long ago, on the largest asteroid in our star system, Vesta, a peak was discovered that somewhat exceeds Olympus in terms of parameters. Perhaps it is the highest in the solar system.
Jupiter's four Galilean moons are the largest in the solar system.
In addition to Saturn, all gas giants, some asteroids and Saturn's moon Rhea have rings.
What system of stars is closest to us? The solar system is closest to the star system of the triple star Alpha Centauri (4.36 light years). It is assumed that planets similar to Earth can exist in it.
To kids about planets
How to explain to children what the solar system is? Her model, which can be made with the kids, will help here. To create planets, you can use plasticine or ready-made plastic (rubber) balls, as shown below. At the same time, it is necessary to observe the ratio between the sizes of the “planets”, so that the model of the solar system really helps to form the correct ideas about space in children.
You will also need toothpicks that will hold our heavenly bodies, and you can use as a background dark leaf cardboard with small dots imitating stars applied with paint. With the help of such an interactive toy, it will be easier for children to understand what the solar system is.
The future of the solar system
The article described in detail what the solar system is. Despite its seeming stability, our Sun, like everything in nature, is evolving, but this process, by our standards, is very long. The supply of hydrogen fuel in its bowels is huge, but not infinite. So, according to the hypotheses of scientists, it will end in 6.4 billion years. As it burns out, the solar core will become denser and hotter, and the outer shell of the star will become wider and wider. The luminosity of the star will also increase. It is assumed that in 3.5 billion years, because of this, the climate on Earth will be similar to Venusian, and life on it in the usual sense for us will no longer be possible. There will be no water left at all, under the influence high temperatures it will escape into outer space. Subsequently, according to scientists, the Earth will be absorbed by the Sun and dissolved in its depths.
The outlook is not very bright. However, progress does not stand still, and, perhaps, by that time, new technologies will allow mankind to master other planets, over which other suns shine. After all, how many "solar" systems in the world, scientists do not yet know. There are probably countless of them, and among them it is quite possible to find one suitable for human habitation. Which "solar" system will become our new home is not so important. Human civilization will be preserved, and another page will begin in its history...
Quick answer: 8 planets.
The solar system is a planetary system that includes the central star, which is the Sun, as well as all other natural space objects, which in turn revolve around the Sun.
Interestingly, most of the entire mass of the solar system falls on itself, while the rest falls on 8 planets. Yes, yes, there are 8 planets in the solar system, not 9, as some people believe. Why do they think so? One of the reasons is that they mistake the Sun for another planet, but in fact it is the only star that is part of the solar system. But in fact, everything is simpler - Pluto used to be considered a planet, but now it is considered a dwarf planet.
Let's start the review of the planets, starting with the closest to the Sun.
Mercury
This planet was named after the ancient Roman god of trade - the swift-footed Mercury. The fact is that it moves much faster than other planets.
Mercury completely revolves around the Sun in 88 Earth days, while the duration of one sidereal day on Mercury is 58.65 Earth days.
Relatively little is known about the planet, and one of the reasons is that Mercury is too close to the Sun.
Venus
Venus is the second so-called inner planet of the solar system, which was named after the goddess of love Venus. It is worth noting that this is the only planet that got its name in honor of a female deity, and not a male one.
Venus is very similar to Earth, not only in size, but also in composition and even gravity.
It is believed that once on Venus there were many oceans, similar topics what we have. However, some time ago, the planet warmed up so much that all the water evaporated, leaving behind only rocks. Water vapor was carried into outer space.
Earth
The third planet is Earth. It is the largest planet among the terrestrial planets.
It was formed about 4.5 billion years ago, after which it was almost immediately joined by its only satellite, which is the Moon. It is believed that life on Earth appeared about 3.9 billion years ago, and over time, its biosphere began to change in better side, which made it possible to form the ozone layer, increase the growth of aerobic organisms, etc. All this, among other things, allows us to exist even now.
Mars
Mars closes the four terrestrial planets. The planet is named after the ancient Roman god of war Mars. This planet is also called red because its surface has a reddish tint due to iron oxide.
Mars has a surface pressure 160 times less than Earth's. On the surface are craters similar to those that can be observed on the moon. There are also volcanoes, deserts, valleys and even ice caps.
Mars has two moons: Deimos and Phobos.
Jupiter
It is the fifth planet from the Sun and the first among the giant planets. By the way, the largest in the solar system, which got its name in honor of the ancient Roman supreme god of thunder.
Jupiter has been known for a long time, which is reflected in ancient myths and legends. Has a very a large number of satellites - 67, to be exact. Interestingly, some of them were discovered several centuries ago. So, Galileo Galilei himself discovered 4 satellites in 1610.
Jupiter can sometimes be seen with the naked eye, as was the case in 2010.
Saturn
Saturn is the second largest planet in the solar system. It was named after the Roman god of agriculture.
It is known that Saturn consists of hydrogen with signs of water, helium, ammonia, methane and other heavy elements. An unusual wind speed has been noticed on the planet - about 1800 kilometers per hour.
Saturn has visible rings that are mostly ice, dust, and other elements. Saturn also has 63 moons, one of which, Titan, surpasses even Mercury in size.
Uranus
The seventh planet in terms of distance from the Sun. It was discovered relatively recently (in 1781) by William Herschel and was named after the sky god.
Uranus is the first planet to be discovered with a telescope between the Middle Ages and modern times. Interestingly, despite the fact that the planet can sometimes be seen with the naked eye, before its discovery, it was commonly believed that it was a dim star.
Uranus has a lot of ice, but there is no metallic hydrogen. The atmosphere of the planet is made up of helium and hydrogen, as well as methane.
Uranus a complex system rings, there are also 27 satellites at once.
Neptune
Finally, we have reached the eighth and last planet of the solar system. The planet is named after the Roman god of the seas.
Neptune was discovered in 1846, and, interestingly, not with the help of observations, but thanks to mathematical calculations. Initially, only one of its satellites was discovered, although the remaining 13 were not known until the 20th century.
Neptune's atmosphere is made up of hydrogen, helium, and possibly nitrogen. Here the most are raging strong winds, the speed of which reaches a fantastic 2100 km / h. AT upper layers atmospheric temperature is about 220°C.
Neptune has an underdeveloped ring system.
