How our solar system works. Structure and composition of the Solar system

The science

We all know from childhood that at the center of our solar system is the Sun, around which the four closest terrestrial planets revolve, including Mercury, Venus, Earth and Mars. They are followed by four gas giant planets: Jupiter, Saturn, Uranus and Neptune.

After Pluto ceased to be considered a planet in the solar system in 2006 and became a dwarf planet, the number of main planets was reduced to 8.

Although many people know the general structure, there are many myths and misconceptions regarding the solar system.

Here are 10 facts you might not know about the solar system.

1. The hottest planet is not closest to the Sun

Many people know that Mercury is the planet closest to the Sun, whose distance is almost two times less than the distance from the Earth to the Sun. It's no wonder that many people believe that Mercury is the hottest planet.

In fact Venus is the hottest planet in the solar system- the second planet close to the Sun, where the average temperature reaches 475 degrees Celsius. This is enough to melt tin and lead. At the same time, the maximum temperature on Mercury is about 426 degrees Celsius.

But due to the lack of an atmosphere, the surface temperature of Mercury can vary by hundreds of degrees, while the carbon dioxide on the surface of Venus maintains a virtually constant temperature at any time of the day or night.

2. The edge of the solar system is a thousand times further from Pluto

We are used to thinking that the solar system extends to the orbit of Pluto. Today, Pluto is not even considered a major planet, but this idea remains in the minds of many people.

Scientists have discovered many objects orbiting the Sun that are much further than Pluto. These are the so-called trans-Neptunian or Kuiper belt objects. The Kuiper Belt extends over 50-60 astronomical units (An astronomical unit, or the average distance from the Earth to the Sun, is 149,597,870,700 m).

3. Almost everything on planet Earth is a rare element

The earth is mainly composed of iron, oxygen, silicon, magnesium, sulfur, nickel, calcium, sodium and aluminum.

Although all of these elements have been found in different places throughout the universe, they are only traces of elements that dwarf the abundance of hydrogen and helium. Thus, the Earth is mostly composed of rare elements. This does not indicate any special place on planet Earth, since the cloud from which the Earth formed contained large amounts of hydrogen and helium. But because they are light gases, they were carried into space by the sun's heat as the Earth formed.

4. The solar system has lost at least two planets

Pluto was originally considered a planet, but due to its very small size (much smaller than our Moon), it was renamed a dwarf planet. Astronomers also the planet Vulcan was once believed to exist, which is closer to the Sun than Mercury. Its possible existence was discussed 150 years ago to explain some features of Mercury's orbit. However, later observations ruled out the possibility of Vulcan's existence.

In addition, recent research has shown that it may someday there was a fifth giant planet, similar to Jupiter, which orbited the Sun, but was thrown out of the Solar System due to gravitational interaction with other planets.

5. Jupiter has the largest ocean of any planet

Jupiter, which orbits in cold space five times farther from the sun than planet Earth, was able to retain much higher levels of hydrogen and helium during formation than our planet.

One could even say that Jupiter is mainly composed of hydrogen and helium. Given the planet's mass and chemical composition, as well as the laws of physics, under cold clouds, an increase in pressure should lead to the transition of hydrogen to a liquid state. That is, on Jupiter there should be deepest ocean of liquid hydrogen.

According to computer models, this planet not only has the largest ocean in the solar system, its depth is approximately 40,000 km, that is, equal to the circumference of the Earth.

6. Even the smallest bodies in the solar system have satellites

It was once believed that only large objects such as planets could have natural satellites or moons. The existence of moons is sometimes even used to determine what a planet actually is. It seems counterintuitive that small cosmic bodies could have enough gravity to hold a satellite. After all, Mercury and Venus don't have any, and Mars only has two tiny moons.

But in 1993, the Galileo interplanetary station discovered a Dactyl satellite near the asteroid Ida, only 1.6 km wide. Since then it has been found moons orbiting about 200 other small planets, which made defining a “planet” much more difficult.

7. We live inside the Sun

We usually think of the Sun as a huge hot ball of light located at a distance of 149.6 million km from Earth. In fact The Sun's outer atmosphere extends much further than the visible surface.

Our planet orbits within its thin atmosphere, and we can see this when gusts of solar wind cause the aurora to appear. In this sense, we live inside the Sun. But the solar atmosphere does not end on Earth. The aurora can be observed on Jupiter, Saturn, Uranus and even distant Neptune. The outermost region of the solar atmosphere is the heliosphere extends over at least 100 astronomical units. This is about 16 billion kilometers. But since the atmosphere is drop-shaped due to the movement of the Sun in space, its tail can reach from tens to hundreds of billions of kilometers.

8. Saturn isn't the only planet with rings

While Saturn's rings are by far the most beautiful and easy to observe, Jupiter, Uranus and Neptune also have rings. While Saturn's bright rings are made of icy particles, Jupiter's very dark rings are mostly dust particles. They may contain minor fragments of disintegrated meteorites and asteroids and possibly particles of the volcanic moon Io.

Uranus's ring system is slightly more visible than Jupiter's and may have formed after the collision of small moons. Neptune's rings are faint and dark, just like Jupiter's. Faint rings of Jupiter, Uranus and Neptune impossible to see through small telescopes from Earth, because Saturn became most famous for its rings.

Contrary to popular belief, there is a body in the solar system with an atmosphere essentially similar to that of Earth. This is Saturn's moon Titan.. It is larger than our Moon and is close in size to the planet Mercury. Unlike the atmosphere of Venus and Mars, which are much thicker and thinner, respectively, than that of Earth, and consist of carbon dioxide, Titan's atmosphere is mostly nitrogen.

The Earth's atmosphere is approximately 78 percent nitrogen. The similarity to the Earth's atmosphere, and especially the presence of methane and other organic molecules, led scientists to believe that Titan could be considered an analogue of the early Earth, or that some kind of biological activity was present there. For this reason, Titan is considered the best place in the solar system to search for signs of life.

The boundless space, despite the apparent chaos, is a fairly harmonious structure. In this gigantic world, the immutable laws of physics and mathematics also apply. All objects in the Universe, from small to large, occupy their specific place, move along given orbits and trajectories. This order was established more than 15 billion years ago, since the formation of the Universe. Our solar system, the cosmic metropolis in which we live, is no exception.

Despite its colossal size, the Solar System fits within the human framework of perception, being the most studied part of the cosmos, with clearly defined boundaries.

Origin and main astrophysical parameters

In a Universe where there are an infinite number of stars, there are certainly other solar systems. There are approximately 250-400 billion stars in our Milky Way galaxy alone, so it cannot be ruled out that worlds with other life forms may exist in the depths of space.

Even 150-200 years ago, people had meager ideas about space. The size of the Universe was limited by telescope lenses. The Sun, Moon, planets, comets and asteroids were the only known objects, and the entire cosmos was measured by the size of our galaxy. The situation changed dramatically at the beginning of the 20th century. Astrophysical exploration of outer space and the work of nuclear physicists over the past 100 years have given scientists insight into how the Universe began. The processes that led to the formation of stars and provided the building material for the formation of planets became known and understood. In this light, the origin of the solar system becomes clear and explainable.

The Sun, like other stars, is a product of the Big Bang, after which stars formed in space. Objects of large and small sizes appeared. In one of the corners of the Universe, among a cluster of other stars, our Sun was born. By cosmic standards, the age of our star is small, only 5 billion years. At the site of her birth, a gigantic construction site was formed, where, as a result of the gravitational compression of the gas and dust cloud, other objects of the solar system were formed.

Each celestial body took on its own form and took its assigned place. Some celestial bodies, under the influence of the Sun's gravity, became permanent satellites, moving in their own orbit. Other objects ceased to exist as a result of the counteraction of centrifugal and centripetal processes. This whole process took about 4.5 billion years. The mass of the entire solar economy is 1.0014 M☉. Of this mass, 99.8% is the Sun itself. Only 0.2% of the mass comes from other space objects: planets, satellites and asteroids, fragments of cosmic dust orbiting around it.

The orbit of the Solar System has an almost circular shape, and the orbital speed coincides with the speed of the galactic spiral. As it passes through the interstellar medium, the stability of the solar system is given by gravitational forces acting within our galaxy. This in turn provides stability to other objects and bodies of the Solar System. The movement of the Solar system takes place at a considerable distance from the super-dense star clusters of our galaxy, which carry potential danger.

In terms of its size and number of satellites, our solar system cannot be called small. There are small solar systems in space that have one or two planets and, due to their size, are barely noticeable in outer space. Representing a massive galactic object, the solar system moves through space at a tremendous speed of 240 km/s. Even despite such a rapid run, the Solar System completes a full revolution around the center of the galaxy in 225 -250 million years.

The exact intergalactic address of our star system is as follows:

• local interstellar cloud;
• local bubble in the Orion-Cygnus arm;
• The Milky Way galaxy, part of the Local Group of galaxies.

The Sun is the central object of our system and is one of the 100 billion stars that make up the Milky Way galaxy. In terms of its size, it is a medium-sized star and belongs to the spectral class G2V Yellow dwarfs. The diameter of the star is 1 million. 392 thousand kilometers, and it is in the middle of its life cycle.

For comparison, the size of Sirius, the brightest star, is 2 million 381 thousand km. Aldebaran has a diameter of almost 60 million km. The huge star Betelgeuse is 1000 times larger than our Sun. The size of this supergiant exceeds the size of the solar system.

Our star's closest neighborhood neighbor is considered to be Proxima Centauri, which will take about 4 years to reach at the speed of light.

The Sun, thanks to its enormous mass, holds eight planets near it, many of which, in turn, have their own systems. The position of objects moving around the Sun is clearly demonstrated by the diagram of the Solar System. Almost all the planets in the solar system move around our star in the same direction, along with the rotating Sun. The orbits of the planets are practically in the same plane, have different shapes and move around the center of the system at different speeds. Movement around the Sun is counterclockwise and in one plane. Only comets and other objects, mainly those located in the Kuiper belt, have orbits with a large angle of inclination to the ecliptic plane.

Today we know exactly how many planets there are in the Solar System, there are 8 of them. All celestial bodies of the Solar System are at a certain distance from the Sun, periodically moving away or approaching it. Accordingly, each of the planets has its own, different from the others, astrophysical parameters and characteristics. It should be noted that 6 of the 8 planets in the Solar System rotate around their axis in the direction in which our star rotates around its own axis. Only Venus and Uranus rotate in the opposite direction. In addition, Uranus is the only planet in the solar system that practically lies on its side. Its axis is inclined 90° to the ecliptic line.

Nicolaus Copernicus demonstrated the first model of the solar system. In his view, the Sun was the central object of our world, around which other planets, including our Earth, revolve. Subsequently, Kepler, Galileo, and Newton improved this model by placing objects in it in accordance with mathematical and physical laws.

Looking at the presented model, one can imagine that the orbits of space objects are located at equal distances from each other. The solar system in nature looks completely different. The greater the distance to the planets of the solar system from the Sun, the greater the distance between the orbit of the previous celestial object. The table of distances of objects from the center of our star system allows you to visually imagine the scale of the solar system.

As the distance from the Sun increases, the speed of rotation of the planets around the center of the Solar System slows down. Mercury, the planet closest to the Sun, completes a full revolution around our star in just 88 Earth days. Neptune, located at a distance of 4.5 billion kilometers from the Sun, makes a complete revolution in 165 Earth years.

Despite the fact that we are dealing with a heliocentric model of the solar system, many planets have their own systems consisting of natural satellites and rings. The satellites of the planets move around the mother planets and obey the same laws.

Most of the satellites of the Solar System rotate synchronously around their planets, always turning the same side towards them. The Moon is also always turned to the Earth with one side.

Only two planets, Mercury and Venus, do not have natural satellites. Mercury is even smaller in size than some of its satellites.

Center and boundaries of the solar system

The main and central object of our system is the Sun. It has a complex structure and consists of 92% hydrogen. Only 7% is used for helium atoms, which, when interacting with hydrogen atoms, become fuel for an endless nuclear chain reaction. At the center of the star there is a core with a diameter of 150-170 thousand km, heated to a temperature of 14 million K.

A brief description of the star can be reduced to a few words: it is a huge natural thermonuclear reactor. Moving from the center of the star to its outer edge, we find ourselves in the convective zone, where energy transfer and plasma mixing occur. This layer has a temperature of 5800K. The visible part of the Sun is the photosphere and chromosphere. Our star is crowned by the solar corona, which is the outer shell. The processes occurring inside the Sun affect the entire state of the Solar System. Its light warms our planet, the force of attraction and gravity keep objects in near space at a certain distance from each other. As the intensity of internal processes decreases, our star will begin to cool. The consumable stellar material will lose its density, causing the star's body to expand. Instead of a yellow dwarf, our Sun will turn into a huge Red Giant. For now, our Sun remains the same hot and bright star.

The border of the kingdom of our star is the Kuiper belt and the Oort cloud. These are extremely remote areas of outer space that are influenced by the Sun. In the Kuiper belt and in the Oort Cloud there are a lot of other objects of various sizes that in one way or another influence the processes occurring inside the Solar system.

The Oort Cloud is a hypothetical spherical space that surrounds the Solar System along its entire outer diameter. The distance to this region of space is more than 2 light years. This area is home to comets. It is from there that these rare space guests, long-period comets, come to us

The Kuiper Belt contains residual material that was used during the formation of the Solar System. These are mainly small particles of space ice, a cloud of frozen gas (methane and ammonia). There are also large objects in this area, some of which are dwarf planets, and smaller fragments similar in structure to asteroids. The main known objects of the belt are the dwarf planets of the solar system Pluto, Haumea and Makemake. A spaceship can reach them in one light year.

Between the Kuiper Belt and deep space, a highly sparse region exists at the outer edges of the belt, mostly consisting of remnants of cosmic ice and gas.

Today, it is possible that large trans-Neptunian space objects exist in this region of our star system, one of which is the dwarf planet Sedna.

Brief characteristics of the planets of the solar system

Scientists have calculated that the mass of all planets belonging to our star is no more than 0.1% of the mass of the Sun. However, even among this small amount, 99% of the mass comes from the two largest cosmic objects after the Sun - the planets Jupiter and Saturn. The sizes of the planets in the solar system vary greatly. Among them there are babies and giants, similar in their structure and astrophysical parameters to failed stars.

In astronomy, it is customary to divide all 8 planets into two groups:

• planets with a rocky structure are classified as terrestrial planets;
• planets, which are dense clumps of gas, belong to the group of gas giant planets.

Previously it was believed that our star system includes 9 planets. Only recently, at the end of the 20th century, Pluto was classified as a dwarf planet in the Kuiper belt. Therefore, the question of how many planets are in the solar system today can be firmly answered - eight.

If we arrange the planets of the solar system in order, the map of our world will look like this:

• Venus;
• Earth;
• Jupiter;
• Saturn;
• Uranus;

In the very middle of this parade of planets is the asteroid belt. According to scientists, these are the remains of a planet that existed in the early stages of the solar system, but died as a result of a cosmic cataclysm.

The inner planets Mercury, Venus and Earth are the planets closest to the Sun, closer than other objects in the Solar System, and therefore are completely dependent on the processes occurring on our star. At some distance from them is the ancient God of War - the planet Mars. All four planets are united by similarity in structure and identity of astrophysical parameters, therefore they are classified as planets of the Terrestrial group.

Mercury, a close neighbor of the Sun, is like a hot frying pan. It seems paradoxical that, despite its close location to the hot star, Mercury experiences the most significant temperature differences in our system. During the day, the surface of the planet heats up to 350 degrees Celsius, and at night the cosmic cold rages with a temperature of 170.2 °C. Venus is a real boiling cauldron, where there is enormous pressure and high temperatures. Despite its gloomy and dull appearance, Mars today is of greatest interest to scientists. The composition of its atmosphere, astrophysical parameters similar to those on Earth, and the presence of seasons give hope for the subsequent development and colonization of the planet by representatives of terrestrial civilization.

Gas giants, which for the most part are planets without a solid shell, are interesting for their satellites. Some of them, according to scientists, may represent outer territories in which, under certain conditions, the emergence of life is possible.

The terrestrial planets are separated from the four gas planets by the asteroid belt - the internal boundary beyond which lies the kingdom of the gas giants. Next behind the asteroid belt, Jupiter, with its attraction, balances our solar system. This planet is the largest, largest and densest in the solar system. The diameter of Jupiter is 140 thousand km across. This is five times more than our planet. This gas giant has its own system of satellites, of which there are about 69 pieces. Among them, real giants stand out: the two largest satellites of Jupiter - Ganymede and Calypso - are larger in size than the planet Mercury.

Saturn, the brother of Jupiter, also has a huge size - 116 thousand km. in diameter. Saturn's retinue is no less impressive - 62 satellites. However, this giant stands out in the night sky with something else - a beautiful system of rings encircling the planet. Titan is one of the largest satellites of the solar system. This giant has a diameter of more than 10 thousand km. Among the kingdom of hydrogen, nitrogen and ammonia there can be no known forms of life. However, unlike their host, Saturn's moons have a rocky structure and a hard surface. Some of them have an atmosphere; Enceladus is even supposed to have water.

The series of giant planets continues with Uranus and Neptune. These are cold, dark worlds. Unlike Jupiter and Saturn, where hydrogen predominates, here there is methane and ammonia in the atmosphere. Instead of condensed gas, high-temperature ice is present on Uranus and Neptune. In view of this, both planets were classified into one group - ice giants. Uranus is second in size only to Jupiter, Saturn and Neptune. Neptune's orbit has a diameter of almost 9 billion kilometers. It takes the planet 164 Earth years to go around the Sun.

Mars, Jupiter, Saturn, Uranus and Neptune represent the most interesting objects for study today for scientists.

Last news

Despite the enormous amount of knowledge that humanity possesses today, despite the achievements of modern means of observation and research, a lot of unresolved questions remain. What kind of solar system actually is, which planet may later turn out to be suitable for life?

Man continues to observe the nearest space, making more and more new discoveries. In December 2012, the whole world could watch an enchanting astronomical show - a parade of planets. During this period, all 7 planets of our solar system could be seen in the night sky, including even such distant ones as Uranus and Neptune.

A closer study today is carried out with the help of space automatic probes and devices. Many of them have already managed not only to fly to the most extreme regions of our star system, but also beyond its borders. The first artificially created space objects that managed to reach the boundaries of the solar system were the American probes Pioneer 10 and Pioneer 11.

It is interesting to theoretically speculate how far these devices will be able to advance beyond the borders? Launched in 1977, the American automatic probe Voyager 1, after 40 years of work studying planets, became the first spacecraft to leave our system.

> Planets

Explore everything planets of the solar system in order and study the names, new scientific facts and interesting features of the surrounding worlds with photos and videos.

The solar system is home to 8 planets: Mercury, Venus, Mars, Earth, Jupiter, Saturn, Uranus and Neptune. The first 4 belong to the inner solar system and are considered terrestrial planets. Jupiter and Saturn are the large planets of the solar system and representatives of the gas giants (huge and filled with hydrogen and helium), and Uranus and Neptune are ice giants (large and represented by heavier elements).

Previously, Pluto was considered the ninth planet, but since 2006 it has become a dwarf planet. This dwarf planet was first discovered by Clyde Tomb. It is now one of the largest objects in the Kuiper Belt, a collection of icy bodies on the outer edge of our system. Pluto lost its planetary status after the IAU (International Astronomical Union) revised the concept itself.

According to the IAU decision, a solar system planet is a body that performs an orbital passage around the Sun, endowed with sufficient mass to form into a sphere and clear the area around it of foreign objects. Pluto failed to meet the latter requirement, which is why it became a dwarf planet. Other similar objects include Ceres, Makemake, Haumea and Eris.

With a small atmosphere, harsh surface features and 5 moons, Pluto is considered the most complex dwarf planet and one of the most amazing planets in our solar system.

But scientists have not given up hope of finding the mysterious Planet Nine, after they announced in 2016 a hypothetical object that exerts its gravity on bodies in the Kuiper Belt. According to its parameters, it is 10 times the mass of the Earth and 5000 times more massive than Pluto. Below is a list of planets of the solar system with photos, names, descriptions, detailed characteristics and interesting facts for children and adults.

Variety of planets

Astrophysicist Sergei Popov about gas and ice giants, double star systems and single planets:

Hot planetary coronas

Astronomer Valery Shematovich on the study of gaseous shells of planets, hot particles in the atmosphere and discoveries on Titan:

Terrestrial planets of the solar system

The first 4 planets from the Sun are called terrestrial planets because their surface is rocky. Pluto also has a solid surface layer (frozen), but it is classified as a dwarf planet.

Gas giant planets of the solar system

There are 4 gas giants living in the outer solar system, as they are quite huge and gaseous. But Uranus and Neptune are different because they have more ice. That's why they are also called ice giants. However, all gas giants have one thing in common: they are all made of hydrogen and helium.

The IAU has put forward a definition of a planet:

• The object must be orbiting the Sun;
• Have sufficient mass to take the shape of a ball;
• Clear your orbital path of foreign objects;

Pluto could not meet the latter requirement, since it shares its orbital path with a huge number of Kuiper Belt bodies. But not everyone agreed with the definition. However, dwarf planets such as Eris, Haumea and Makemake appeared on the scene.

Ceres also lives between Mars and Jupiter. It was noticed in 1801 and considered a planet. Some still consider it the 10th planet of the solar system.

Dwarf planets of the solar system

Formation of planetary systems

Astronomer Dmitry Vibe about rocky planets and giant planets, the diversity of planetary systems and hot Jupiters:

Planets of the Solar System in order

The following describes the characteristics of the 8 main planets of the Solar System in order from the Sun:

The first planet from the Sun is Mercury

Mercury is the first planet from the Sun. Rotates in an elliptical orbit at a distance of 46-70 million km from the Sun. It takes 88 days for one orbital flight, and 59 days for an axial flight. Due to its slow rotation, a day spans 176 days. The axial tilt is extremely small.

With a diameter of 4887 km, the first planet from the Sun reaches 5% of the Earth's mass. Surface gravity is 1/3 of Earth's. The planet is practically devoid of an atmospheric layer, so it is hot during the day and freezes at night. The temperature ranges between +430°C and -180°C.

There is a crater surface and an iron core. But its magnetic field is inferior to that of the earth. Initially, radar indicated the presence of water ice at the poles. The Messenger apparatus confirmed the assumptions and found deposits at the bottom of craters, which are always immersed in shadow.

The first planet from the Sun is located close to the star, so it can be seen before dawn and just after sunset.

• Title: Messenger of the gods in the Roman pantheon.
• Diameter: 4878 km.
• Orbit: 88 days.
• Length of day: 58.6 days.

The second planet from the Sun is Venus

Venus is the second planet from the Sun. Travels in an almost circular orbit at a distance of 108 million km. It comes closest to Earth and can reduce the distance to 40 million km.

The orbital path takes 225 days, and the axial rotation (clockwise) lasts 243 days. A day spans 117 Earth days. The axial tilt is 3 degrees.

In diameter (12,100 km), the second planet from the Sun is almost identical to the Earth’s and reaches 80% of the Earth’s mass. The gravity indicator is 90% of Earth's. The planet has a dense atmospheric layer, where the pressure is 90 times higher than Earth's. The atmosphere is filled with carbon dioxide with thick sulfur clouds, creating a powerful greenhouse effect. It is because of this that the surface warms up by 460°C (the hottest planet in the system).

The surface of the second planet from the Sun is hidden from direct observation, but scientists were able to create a map using radar. Covered by large volcanic plains with two huge continents, mountains and valleys. There are also impact craters. A weak magnetic field is observed.

• Discovery: The ancients saw without the use of tools.
• Name: Roman goddess responsible for love and beauty.
• Diameter: 12104 km.
• Orbit: 225 days.
• Day length: 241 days.

The third planet from the Sun is Earth

Earth is the third planet from the Sun. It is the largest and densest of the inner planets. The orbital path is 150 million km away from the Sun. It has a single companion and developed life.

The orbital flyby takes 365.25 days, and the axial rotation takes 23 hours, 56 minutes and 4 seconds. The length of the day is 24 hours. The axial tilt is 23.4 degrees, and the diameter is 12742 km.

The third planet from the Sun was formed 4.54 billion years ago and for most of its existence the Moon was nearby. It is believed that the satellite appeared after a huge object crashed into the Earth and tore material into orbit. It is the Moon that stabilizes the Earth's axial tilt and acts as the source of the formation of tides.

The satellite's diameter covers 3,747 km (27% of Earth's) and is located at a distance of 362,000-405,000 km. Experiencing planetary gravitational influence, due to which it slowed down its axial rotation and fell into a gravitational block (therefore, one side is turned towards the Earth).

The planet is protected from stellar radiation by a powerful magnetic field formed by the active core (molten iron).

• Diameter: 12760 km.
• Orbit: 365.24 days.
• Day length: 23 hours and 56 minutes.

The fourth planet from the Sun is Mars

Mars is the fourth planet from the Sun. The Red Planet moves along an eccentric orbital path - 230 million km. One flight around the Sun takes 686 days, and an axial revolution takes 24 hours and 37 minutes. It is located at an inclination of 25.1 degrees, and the day lasts 24 hours and 39 minutes. Its inclination resembles that of the Earth, which is why it has seasons.

The diameter of the fourth planet from the Sun (6792 km) is half that of Earth, and its mass reaches 1/10 of Earth’s. Gravity indicator – 37%.

Mars has no protection as a magnetic field, so the original atmosphere was destroyed by the solar wind. The devices recorded the outflow of atoms into space. As a result, the pressure reaches 1% of the earth's, and the thin atmospheric layer is represented by 95% carbon dioxide.

The fourth planet from the Sun is extremely frosty, with temperatures dropping to -87°C in winter and rising to -5°C in summer. This is a dusty place with giant storms that can cover the entire surface.

• Discovery: The ancients saw without the use of tools.
• Name: Roman god of war.
• Diameter: 6787 km.
• Orbit: 687 days.
• Day length: 24 hours and 37 minutes.

The fifth planet from the Sun is Jupiter

Jupiter is the fifth planet from the Sun. In addition, this is the largest planet in the system, which is 2.5 times more massive than all the planets and covers 1/1000 of the solar mass.

It is distant from the Sun by 780 million km and spends 12 years on its orbital path. Filled with hydrogen (75%) and helium (24%) and may have a rocky core immersed in liquid metallic hydrogen with a diameter of 110,000 km. The total planetary diameter is 142984 km.

In the upper layer of the atmosphere there are 50-kilometer clouds, represented by ammonia crystals. They are in bands moving at different speeds and latitudes. The Great Red Spot, a large-scale storm, seems remarkable.

The fifth planet from the Sun spends 10 hours on its axial rotation. This is a rapid speed, which means the equatorial diameter is 9000 km larger than the polar one.

• Discovery: The ancients saw without the use of tools.
• Name: the main god in the Roman pantheon.
• Diameter: 139822 km.
• Orbit: 11.9 years.
• Length of day: 9.8 hours.

The sixth planet from the Sun is Saturn

Saturn is the sixth planet from the Sun. Saturn is in 2nd position in terms of scale in the system, exceeding the Earth's radius by 9 times (57,000 km) and 95 times more massive.

It is distant from the Sun by 1400 million km and spends 29 years on its orbital flight. Filled with hydrogen (96%) and helium (3%). May have a rocky core in liquid metallic hydrogen with a diameter of 56,000 km. The upper layers are represented by liquid water, hydrogen, ammonium hydrosulfide and helium.

The core is heated to 11,700°C and produces more heat than the planet receives from the Sun. The higher we rise, the lower the degree drops. At the top, the temperature is maintained at -180°C and 0°C at a depth of 350 km.

The cloud layers of the sixth planet from the Sun resemble the picture of Jupiter, but they are fainter and wider. There is also the Great White Spot, a brief periodic storm. It spends 10 hours and 39 minutes on an axial rotation, but it is difficult to give an exact figure, since there are no fixed surface features.

• Discovery: The ancients saw without the use of tools.
• Name: god of the economy in the Roman pantheon.
• Diameter: 120500 km.
• Orbit: 29.5 days.
• Length of day: 10.5 hours.

The seventh planet from the Sun is Uranus

Uranus is the seventh planet from the Sun. Uranus is a representative of the ice giants and is the 3rd largest in the system. Its diameter (50,000 km) is 4 times greater than that of Earth and 14 times more massive.

It is distant by 2900 million km and spends 84 years on its orbital path. What’s surprising is that the planet’s axial tilt (97 degrees) literally rotates on its side.

It is believed that there is a small rocky core around which a mantle of water, ammonia and methane is concentrated. This is followed by a hydrogen, helium and methane atmosphere. The seventh planet from the Sun also stands out in that it does not radiate more internal heat, so the temperature mark drops to -224°C (the coldest planet).

• Discovery: In 1781, noticed by William Herschel.
• Name: personification of the sky.
• Diameter: 51120 km.
• Orbit: 84 years.
• Duration of the day: 18 hours.

Neptune is the eighth planet from the Sun. Neptune has been considered the official last planet in the solar system since 2006. The diameter is 49,000 km, and its massiveness is 17 times greater than that of Earth.

It is distant by 4500 million km and spends 165 years on an orbital flight. Due to its remoteness, the planet receives only 1% of solar radiation (compared to Earth). The axial tilt is 28 degrees, and the rotation takes 16 hours.

The meteorology of the eighth planet from the Sun is more pronounced than that of Uranus, so powerful storm activity can be seen at the poles in the form of dark spots. The wind accelerates to 600 m/s, and the temperature drops to -220°C. The core heats up to 5200°C.

• Discovery: 1846
• Name: Roman god of water.
• Diameter: 49530 km.
• Orbit: 165 years.
• Duration of the day: 19 hours.

This is a small world, smaller in size than Earth's satellite. The orbit intersects with Neptune in 1979-1999. it could be considered the 8th planet in terms of distance from the Sun. Pluto will remain beyond Neptune's orbit for more than two hundred years. The orbital path is inclined to the system plane at 17.1 degrees. Frosty World visited New Horizons in 2015.

• Discovery: 1930 - Clyde Tombaugh.
• Name: Roman god of the underworld.
• Diameter: 2301 km.
• Orbit: 248 years.
• Length of day: 6.4 days.

Planet Nine is a hypothetical object residing in the outer system. Its gravity should explain the behavior of trans-Neptunian objects.

The solar system is a group of planets revolving in specific orbits around a bright star - the Sun. This star is the main source of heat and light in the solar system.

It is believed that our planetary system was formed as a result of the explosion of one or more stars and this happened about 4.5 billion years ago. At first, the solar system was an accumulation of gas and dust particles, however, over time and under the influence of its own mass, the Sun and other planets arose.

Planets of the Solar System

At the center of the solar system is the Sun, around which eight planets move in their orbits: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.

Until 2006, Pluto also belonged to this group of planets; it was considered the 9th planet from the Sun, however, due to its significant distance from the Sun and small size, it was excluded from this list and called a dwarf planet. More precisely, it is one of several dwarf planets in the Kuiper belt.

All of the above planets are usually divided into two large groups: the terrestrial group and the gas giants.

The terrestrial group includes such planets as: Mercury, Venus, Earth, Mars. They are distinguished by their small size and rocky surface, and in addition, they are located closest to the Sun.

Gas giants include: Jupiter, Saturn, Uranus, Neptune. They are characterized by large sizes and the presence of rings, which are ice dust and rocky pieces. These planets consist mainly of gas.

Mercury

This planet is one of the smallest in the solar system, its diameter is 4,879 km. In addition, it is closest to the Sun. This proximity predetermined a significant temperature difference. The average temperature on Mercury during the day is +350 degrees Celsius, and at night - -170 degrees.

1. Mercury is the first planet from the Sun.
2. There are no seasons on Mercury. The tilt of the planet's axis is almost perpendicular to the plane of the planet's orbit around the Sun.
3. The temperature on the surface of Mercury is not the highest, although the planet is located closest to the Sun. He lost first place to Venus.
4. The first research vehicle to visit Mercury was Mariner 10. It conducted a number of demonstration flights in 1974.
5. A day on Mercury lasts 59 Earth days, and a year is only 88 days.
6. Mercury experiences the most dramatic temperature changes, reaching 610 °C. During the day, temperatures can reach 430 °C, and at night -180 °C.
7. The gravity on the planet's surface is only 38% of Earth's. This means that on Mercury you could jump three times as high, and it would be easier to lift heavy objects.
8. The first observations of Mercury through a telescope were made by Galileo Galilei in the early 17th century.
9. Mercury has no natural satellites.
10. The first official map of Mercury's surface was published only in 2009, thanks to data obtained from the Mariner 10 and Messenger spacecraft.

Venus

This planet is the second from the Sun. In size it is close to the diameter of the Earth, the diameter is 12,104 km. In all other respects, Venus differs significantly from our planet. A day here lasts 243 Earth days, and a year lasts 255 days. The atmosphere of Venus is 95% carbon dioxide, which creates a greenhouse effect on its surface. This results in an average temperature on the planet of 475 degrees Celsius. The atmosphere also contains 5% nitrogen and 0.1% oxygen.

1. Venus is the second planet from the Sun in the Solar System.
2. Venus is the hottest planet in the solar system, although it is the second planet from the sun. Surface temperature can reach 475 °C.
   
3. The first spacecraft sent to explore Venus was sent from Earth on February 12, 1961 and was called Venera 1.
4. Venus is one of two planets whose direction of rotation around its axis is different from most planets in the solar system.
5. The planet's orbit around the Sun is very close to circular.
6. The day and night temperatures of the surface of Venus are practically the same due to the large thermal inertia of the atmosphere.
7. Venus makes one revolution around the Sun in 225 Earth days, and one revolution around its axis in 243 Earth days, that is, one day on Venus lasts more than one year.
8. The first observations of Venus through a telescope were made by Galileo Galilei at the beginning of the 17th century.
9. Venus has no natural satellites.
10. Venus is the third brightest object in the sky, after the Sun and Moon.

Earth

Our planet is located at a distance of 150 million km from the Sun, and this allows us to create on its surface a temperature suitable for the existence of liquid water, and, therefore, for the emergence of life.

Its surface is 70% covered with water, and it is the only planet to contain such an amount of liquid. It is believed that many thousands of years ago, steam contained in the atmosphere created the temperature on the Earth's surface necessary for the formation of water in liquid form, and solar radiation contributed to photosynthesis and the birth of life on the planet.

1. Earth in the solar system is the third planet from the sunsA;
2. Our planet revolves around one natural satellite - the Moon;
   
3. Earth is the only planet not named after a divine being;
4. The Earth's density is the greatest of all the planets in the solar system;
5. The Earth's rotation speed is gradually slowing down;
6. The average distance from the Earth to the Sun is 1 astronomical unit (a conventional measure of length in astronomy), which is approximately 150 million km;
7. The Earth has a magnetic field of sufficient strength to protect living organisms on its surface from harmful solar radiation;
8. The first artificial Earth satellite, called PS-1 (The simplest satellite - 1), was launched from the Baikonur Cosmodrome on the Sputnik launch vehicle on October 4, 1957;
9. In orbit around the Earth, compared to other planets, there is the largest number of spacecraft;
10. Earth is the largest terrestrial planet in the solar system;

Mars

This planet is the fourth from the Sun and is 1.5 times more distant from it than the Earth. The diameter of Mars is smaller than Earth's and is 6,779 km. The average air temperature on the planet ranges from -155 degrees to +20 degrees at the equator. The magnetic field on Mars is much weaker than that of Earth, and the atmosphere is quite thin, which allows solar radiation to unimpededly affect the surface. In this regard, if there is life on Mars, it is not on the surface.

When surveyed with the help of Mars rovers, it was found that there are many mountains on Mars, as well as dried river beds and glaciers. The surface of the planet is covered with red sand. It is iron oxide that gives Mars its color.

1. Mars is located in the fourth orbit from the Sun;
2. The Red Planet is home to the tallest volcano in the solar system;
   
3. Of the 40 exploration missions sent to Mars, only 18 were successful;
4. Mars is home to some of the largest dust storms in the solar system;
5. In 30-50 million years, there will be a system of rings around Mars, like Saturn's;
6. Debris from Mars has been found on Earth;
7. The Sun from the surface of Mars looks half as big as from the surface of the Earth;
   
8. Mars is the only planet in the solar system that has polar ice caps;
9. Two natural satellites revolve around Mars - Deimos and Phobos;
10. Mars has no magnetic field;

Jupiter

This planet is the largest in the solar system and has a diameter of 139,822 km, which is 19 times larger than Earth. A day on Jupiter lasts 10 hours, and a year is approximately 12 Earth years. Jupiter is mainly composed of xenon, argon and krypton. If it were 60 times larger, it could become a star due to a spontaneous thermonuclear reaction.

The average temperature on the planet is -150 degrees Celsius. The atmosphere consists of hydrogen and helium. There is no oxygen or water on its surface. There is an assumption that there is ice in the atmosphere of Jupiter.

1. Jupiter is located in the fifth orbit from the Sun;
2. In the Earth's sky, Jupiter is the fourth brightest object, after the Sun, Moon and Venus;
   
3. Jupiter has the shortest day of all the planets in the solar system;
4. In the atmosphere of Jupiter, one of the longest and most powerful storms in the solar system rages, better known as the Great Red Spot;
5. Jupiter's moon Ganymede is the largest moon in the solar system;
6. Jupiter is surrounded by a thin system of rings;
7. Jupiter was visited by 8 research vehicles;
   
8. Jupiter has a strong magnetic field;
   
9. If Jupiter were 80 times more massive, it would become a star;
10. There are 67 natural satellites orbiting Jupiter. This is the largest in the Solar System;

Saturn

This planet is the second largest in the solar system. Its diameter is 116,464 km. It is most similar in composition to the Sun. A year on this planet lasts quite a long time, almost 30 Earth years, and a day lasts 10.5 hours. The average surface temperature is -180 degrees.

Its atmosphere consists mainly of hydrogen and a small amount of helium. Thunderstorms and auroras often occur in its upper layers.

1. Saturn is the sixth planet from the Sun;
2. Saturn's atmosphere contains the strongest winds in the solar system;
   
3. Saturn is one of the least dense planets in the solar system;
   
4. Surrounding the planet is the largest ring system in the Solar System;
5. One day on the planet lasts almost one Earth year and is equal to 378 Earth days;
6. Saturn was visited by 4 research spacecraft;
7. Saturn, together with Jupiter, constitutes approximately 92% of the total planetary mass of the Solar System;
8. One year on the planet lasts 29.5 Earth years;
9. There are 62 known natural satellites orbiting the planet;
10. Currently, the automatic interplanetary station Cassini is studying Saturn and its rings;

Uranus

Uranus, computer artwork.

Uranus is the third largest planet in the solar system and the seventh from the Sun. It has a diameter of 50,724 km. It is also called the “ice planet”, as the temperature on its surface is -224 degrees. A day on Uranus lasts 17 hours, and a year lasts 84 Earth years. Moreover, summer lasts as long as winter - 42 years. This natural phenomenon is due to the fact that the axis of that planet is located at an angle of 90 degrees to the orbit and it turns out that Uranus seems to be “lying on its side.”

1. Uranus is located in the seventh orbit from the Sun;
2. The first person to learn about the existence of Uranus was William Herschel in 1781;
   
3. Uranus has only been visited by one spacecraft, Voyager 2 in 1982;
4. Uranus is the coldest planet in the solar system;
5. The plane of Uranus' equator is inclined to the plane of its orbit at almost a right angle - that is, the planet rotates retrograde, "lying on its side slightly upside down";
6. The moons of Uranus bear names taken from the works of William Shakespeare and Alexander Pope, rather than Greek or Roman mythology;
7. A day on Uranus lasts about 17 Earth hours;
8. There are 13 known rings around Uranus;
9. One year on Uranus lasts 84 Earth years;
10. There are 27 known natural satellites orbiting Uranus;

Neptune

Neptune is the eighth planet from the Sun. It is similar in composition and size to its neighbor Uranus. The diameter of this planet is 49,244 km. A day on Neptune lasts 16 hours, and a year is equal to 164 Earth years. Neptune is an ice giant and for a long time it was believed that no weather phenomena occur on its icy surface. However, it was recently discovered that Neptune has raging vortices and wind speeds that are the highest among the planets in the solar system. It reaches 700 km/h.

Neptune has 14 moons, the most famous of which is Triton. It is known to have its own atmosphere.

Neptune also has rings. This planet has 6 of them.

1. Neptune is the most distant planet in the Solar System and occupies the eighth orbit from the Sun;
2. Mathematicians were the first to know about the existence of Neptune;
   
3. There are 14 satellites circling around Neptune;
4. Neputna's orbit is removed from the Sun by an average of 30 AU;
5. One day on Neptune lasts 16 Earth hours;
6. Neptune has only been visited by one spacecraft, Voyager 2;
7. There is a system of rings around Neptune;
8. Neptune has the second highest gravity after Jupiter;
9. One year on Neptune lasts 164 Earth years;
10. The atmosphere on Neptune is extremely active;

1. Jupiter is considered the largest planet in the solar system.
2. There are 5 dwarf planets in the Solar System, one of which has been reclassified as Pluto.
3. There are very few asteroids in the Solar System.
4. Venus is the hottest planet in the solar system.
5. About 99% of the space (by volume) is occupied by the Sun in the Solar System.
6. The satellite of Saturn is considered one of the most beautiful and original places in the solar system. There you can see a huge concentration of ethane and liquid methane.
7. Our solar system has a tail that resembles a four-leaf clover.
8. The sun follows a continuous 11-year cycle.
9. There are 8 planets in the solar system.
10. The Solar System is fully formed thanks to a large gas and dust cloud.
11. Spacecraft have flown to all the planets of the solar system.
12. Venus is the only planet in the solar system that rotates counterclockwise around its axis.
13. Uranus has 27 satellites.
14. The largest mountain is on Mars.
15. A huge mass of objects in the solar system fell on the sun.
16. The solar system is part of the Milky Way galaxy.
17. The sun is the central object of the solar system.
18. The solar system is often divided into regions.
19. The Sun is a key component of the Solar System.
20. The solar system was formed approximately 4.5 billion years ago.
21. The most distant planet in the solar system is Pluto.
22. Two regions in the Solar System are filled with small bodies.
23. The solar system was built contrary to all the laws of the Universe.
24. If you compare the solar system and space, then it is just a grain of sand in it.
25. Over the past few centuries, the solar system has lost 2 planets: Vulcan and Pluto.
26. Researchers claim that the solar system was created artificially.
27. The only satellite of the Solar System that has a dense atmosphere and whose surface cannot be seen due to cloud cover is Titan.
28. The region of the solar system that lies beyond the orbit of Neptune is called the Kuiper belt.
29. The Oort cloud is the region of the solar system that serves as the source of a comet and a long orbital period.
30. Every object in the solar system is held there due to the force of gravity.
31. The leading theory of the solar system involves the emergence of planets and moons from a huge cloud.
32. The solar system is considered the most secret particle of the Universe.
33. There is a huge asteroid belt in the solar system.
34. On Mars you can see the eruption of the largest volcano in the solar system, which is called Olympus.
35. Pluto is considered to be the outskirts of the solar system.
36. Jupiter has a large ocean of liquid water.
37. The Moon is the largest satellite of the Solar System.
38. Pallas is considered the largest asteroid in the solar system.
39. The brightest planet in the solar system is Venus.
40. The solar system is mostly made of hydrogen.
41. The Earth is an equal member of the solar system.
42. The sun heats up slowly.
43. Oddly enough, the largest reserves of water in the solar system are in the sun.
44. The equator plane of each planet in the solar system diverges from the orbital plane.
45. The satellite of Mars called Phobos is an anomaly in the solar system.
46. The solar system can amaze with its diversity and scale.
47. The planets of the solar system are influenced by the sun.
48. The outer shell of the Solar System is considered to be the haven of satellites and gas giants.
49. A huge number of planetary satellites of the solar system are dead.
50. The largest asteroid, with a diameter of 950 km, is called Ceres.

Not so long ago, any educated person, when asked how many planets are in the solar system, would have answered without hesitation - nine. And he would be right. If you don’t particularly follow events in the world of astronomy and are not a regular viewer of the Discovery Channel, then today you will answer the same question. However, this time you will be wrong.

And here's the thing. In 2006, namely, on August 26, 2.5 thousand participants in the congress of the International Astronomical Union made a sensational decision and actually crossed out Pluto from the list of planets of the solar system, since 76 years after its discovery it no longer met the requirements set by scientists for planets.

Let's first figure out what a planet is, and also how many planets in the solar system astronomers have left for us, and consider each of them separately.

A little history

Previously, a planet was considered to be any body that orbits a star, glows with light reflected from it, and is larger than an asteroid.

Even in Ancient Greece, they mentioned seven luminous bodies that move across the sky against the backdrop of fixed stars. These cosmic bodies were: the Sun, Mercury, Venus, Moon, Mars, Jupiter and Saturn. The 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 16th century, Nicolaus Copernicus, in his scientific work entitled “On the Revolution of the Celestial Spheres,” came to the conclusion that it was not the Earth, but the Sun that should be at the center of the planetary system. Therefore, the Sun and 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 following definition of a planet.

Planet 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 have a spherical or close to it shape;
the body should not have other large bodies near its orbit;

The body does not have to be a star.

In its turn 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 is a planetary system that consists of a central star - the Sun - and all the natural space objects orbiting around it.

So, today the solar system consists of 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. Gas giants are composed mainly of hydrogen and helium.

The sizes of the planets of the Solar System vary both within groups and between groups. Thus, gas giants are much larger and more massive than terrestrial planets.
Mercury is closest to the Sun, then as it moves away: 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.

Sun

The Sun is the 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 more than 5000 degrees Kelvin, and the core temperature is more than 13 million K.

The Sun is one of the largest and brightest stars in our galaxy, which is called the Milky Way galaxy. The Sun is located at a distance of about 26 thousand light years from the center of the Galaxy and makes a full revolution around it in about 230-250 million years! For comparison, the Earth makes a full revolution around the Sun in 1 year.

Mercury

Mercury is the smallest planet in the system, which is closest to the Sun. Mercury has no satellites.

The surface of the planet is covered with craters that appeared 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 thin, consists mainly of helium and is inflated by the solar wind. Since the planet is located very close to the Sun and does not have an atmosphere that would retain heat at night, the surface temperature ranges from -180 to +440 degrees Celsius.

By earthly standards, Mercury completes a full revolution around the Sun in 88 days. But a Mercury day is equal to 176 Earth days.

Venus

Venus is the second planet closest to the Sun in the solar system. Venus is only slightly smaller in size than Earth, which is why it is sometimes called “Earth’s sister.” Has no satellites.

The atmosphere consists of carbon dioxide mixed with nitrogen and oxygen. The air pressure on the planet is more than 90 atmospheres, which is 35 times more than on Earth.

Carbon dioxide and the resulting 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.

Earth

Earth is the only planet known today in the Universe on which there is life. 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 Earth's atmosphere is fundamentally different from the atmospheres of other planets due to the presence of life. Most of the atmosphere consists of nitrogen, but also includes oxygen, argon, carbon dioxide and water vapor. The ozone layer and the Earth's magnetic field, in turn, weaken the life-threatening influence of solar and cosmic radiation.

Due to the carbon dioxide contained in the atmosphere, the greenhouse effect also occurs on Earth. It is not as pronounced as on Venus, but without it the air temperature would be about 40°C lower. Without an 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 world's oceans, the remaining 29% are continents and islands.

Mars

Mars is the seventh largest planet in the solar system. “Red Planet”, as it is also called due to the presence of large amounts of iron oxide in the soil. Mars has two satellites: Deimos and Phobos.
The atmosphere of Mars is very thin, 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 changes in some places reach 40 degrees during the day.

Distinctive features of the surface of Mars are impact craters and volcanoes, valleys and deserts, and polar ice caps similar to those on Earth. The highest mountain in the solar system is located on Mars: the extinct volcano Olympus, whose height is 27 km! And also the largest canyon: Valles Marineris, whose depth reaches 11 km and length – 4500 km.

Jupiter

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 emits a huge amount of heat equal to 4 * 1017 W. However, in order to become a star like the Sun, Jupiter must be 70-80 times heavier.

Jupiter has as many as 63 satellites, of which it makes sense to list only the largest - Callisto, Ganymede, Io and Europa. Ganymede is the largest moon in the solar system, even larger than Mercury.

Due to certain processes in the inner atmosphere of Jupiter, many vortex structures appear in its outer atmosphere, for example, bands of clouds in brown-red shades, as well as the Great Red Spot, a giant storm known since the 17th century.

Saturn

Saturn is the second largest planet in the solar system. Saturn's calling card is, of course, its ring system, which consists mainly of icy particles of various sizes (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 planet's outer atmosphere appears calm and uniform, which is explained by a very dense layer of fog. However, wind speeds in some places can reach 1800 km/h.

Uranus

Uranus is the first planet discovered by telescope, and the only planet in the Solar System that orbits the Sun on its side.
Uranus has 27 moons, which are named after Shakespearean heroes. The largest of them are Oberon, Titania and Umbriel.

The composition of the planet differs from gas giants in the presence of a large number of high-temperature modifications of ice. Therefore, along with Neptune, scientists have classified Uranus as an “ice giant.” 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

Neptune is the most distant planet in the solar system from the center. The story of its discovery is interesting: before observing the planet through a telescope, scientists used mathematical calculations to calculate its position in the sky. This happened after the discovery of inexplicable changes in the movement of Uranus in its own orbit.

Today, 13 satellites of Neptune are known to science. The largest of them, Triton, is the only satellite that moves in the direction opposite 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.

In composition, Neptune is very similar to Uranus, therefore it is the second “ice giant”. However, like Jupiter and Saturn, Neptune has an internal source of heat and emits 2.5 times more energy than it receives from the Sun.
The blue color of the planet is given by traces of methane in the outer layers of the atmosphere.

Conclusion
Pluto, unfortunately, did not manage to get into our parade of planets in the solar system. But there is absolutely no need to worry about this, because all the planets remain in their places, despite changes in scientific views and concepts.

So, we answered the question how many planets are there in the solar system. There are only 8 .