Second planet from the sun. What is the solar system - planets (how many there are, the largest and smallest), small bodies and the sun. Amazing discoveries or interesting facts about the planets 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. Four follow them 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 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 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. Considering the mass of the planet and chemical composition, as well as the laws of physics, under cold clouds an increase in pressure should lead to the transition of hydrogen into 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. Polar Lights can be observed on Jupiter, Saturn, Uranus and even distant Neptune. Farthest area solar atmosphere- 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 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 the 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. Only in our galaxy alone Milky Way There are approximately 250-400 billion stars, so it cannot be ruled out that there may be worlds with other life forms 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 came into being. 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 Big Bang, after which star formation occurred 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 heavenly body took its form and took its allotted 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 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. Passing through the interstellar medium, the stability of the solar system is given by gravitational forces, operating 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 next:

• 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 they orbit own axis our star. 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 complex structure and consists of 92% hydrogen. Only 7% will be 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 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. Mostly small particles 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. Located at some distance from them ancient god wars - 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 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 important planets for scientists today. interesting objects for studying.

Last news

Despite the enormous amount of knowledge that humanity possesses today, despite the achievements modern means observations 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 very extreme regions our star system, but also beyond it. 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? The American automatic probe Voyager 1, launched in 1977, after 40 summer job in the study of planets became the first spacecraft who left our system.

The solar system is a planetary system that includes the central star - the Sun - and all the natural objects of space revolving around it. It was formed by gravitational compression of a gas and dust cloud approximately 4.57 billion years ago. We will find out which planets are part of the solar system, how they are located in relation to the Sun and their brief characteristics.

Brief information about the planets of the solar system

The number of planets in the Solar System is 8, and they are classified in order of distance from the Sun:

• Inner planets or terrestrial planets- Mercury, Venus, Earth and Mars. They consist mainly of silicates and metals
• Outer planets– Jupiter, Saturn, Uranus and Neptune are the so-called gas giants. They are much more massive than the terrestrial planets. The largest planets in the solar system, Jupiter and Saturn, consist mainly of hydrogen and helium; The smaller gas giants, Uranus and Neptune, contain methane and carbon monoxide in their atmospheres, in addition to hydrogen and helium.

Rice. 1. Planets of the Solar System.

The list of planets in the Solar System, in order from the Sun, looks like this: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. By listing the planets from largest to smallest, this order changes. The largest planet is Jupiter, followed by Saturn, Uranus, Neptune, Earth, Venus, Mars and finally Mercury.

All planets orbit the Sun in the same direction as the Sun rotates (counterclockwise when viewed from the side north pole Sun).

The biggest angular velocity Mercury possesses - it manages to complete a full revolution around the Sun in just 88 Earth days. And for the most distant planet - Neptune - the orbital period is 165 Earth years.

Most of the planets rotate around their axis in the same direction as they revolve around the Sun. The exceptions are Venus and Uranus, with Uranus rotating almost “lying on its side” (axis tilt is about 90 degrees).

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Table. The sequence of planets in the solar system and their features.

Planet	Distance from the Sun	Circulation period	Rotation period	Diameter, km.	Number of satellites	Density g/cub. cm.
Mercury

Terrestrial planets (inner planets)

The four planets closest to the Sun are composed primarily of heavy elements, have a small number of satellites, they do not have rings. They are largely composed of refractory minerals such as silicates, which form their mantle and crust, and metals, such as iron and nickel, which form their core. Three of these planets—Venus, Earth, and Mars—have atmospheres.

• Mercury- is the closest planet to the Sun and the smallest planet in the system. The planet has no satellites.
• Venus- is close in size to the Earth and, like the Earth, has a thick silicate shell around an iron core and an atmosphere (because of this, Venus is often called the “sister” of the Earth). However, the amount of water on Venus is much less than on Earth, and its atmosphere is 90 times denser. Venus has no satellites.

Venus is the hottest planet in our system, its surface temperature exceeds 400 degrees Celsius. The most likely reason for such a high temperature is Greenhouse effect, arising from a dense atmosphere rich in carbon dioxide.

Rice. 2. Venus is the hottest planet in the solar system

• Earth- is the largest and most dense of the terrestrial planets. The question of whether life exists anywhere other than Earth remains open. Among the terrestrial planets, the Earth is unique (primarily due to its hydrosphere). The Earth's atmosphere is radically different from the atmospheres of other planets - it contains free oxygen. Earth has one natural satellite— The Moon, the only large satellite of the terrestrial planets of the Solar System.
• Mars– smaller than Earth and Venus. It has an atmosphere consisting mainly of carbon dioxide. There are volcanoes on its surface, the largest of which, Olympus, exceeds the size of all terrestrial volcanoes, reaching a height of 21.2 km.

Outer Solar System

The outer region of the Solar System is home to gas giants and their satellites.

• Jupiter- has a mass 318 times that of Earth, and 2.5 times more massive than all other planets combined. It consists mainly of hydrogen and helium. Jupiter has 67 moons.
• Saturn- Known for its extensive ring system, it is the least dense planet in the solar system (its average density is less than that of water). Saturn has 62 satellites.

Rice. 3. Planet Saturn.

• Uranus- the seventh planet from the Sun is the lightest of the giant planets. What makes it unique among other planets is that it rotates “lying on its side”: the inclination of its rotation axis to the ecliptic plane is approximately 98 degrees. Uranus has 27 moons.
• Neptune - last planet in the Solar System. Although slightly smaller than Uranus, it is more massive and therefore denser. Neptune has 14 known moons.

What have we learned?

One of the interesting topics in astronomy is the structure of the solar system. We learned what names the planets of the solar system are, in what sequence they are located in relation to the Sun, what are their distinctive features and brief characteristics. This information is so interesting and educational that it will be useful even for 4th grade children.

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Planets of the solar system - 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.

Also in Ancient Greece mentioned seven luminous bodies that move across the sky against the background 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 Appeal" celestial spheres“came to the conclusion that it is 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.
Last open planet The solar system from 1930 until recently was considered Pluto.

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 should not 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 events occurring in it thermonuclear reactions, 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.

The sun planet 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 most bright 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 planet

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 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 planet

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.

Planet 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 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. 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 planet

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 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 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 planet

Saturn is the second largest planet in the solar system. Business card Saturn is, of course, its ring system, which consists mainly of icy particles different 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 planet

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 planet

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 is Triton. the only satellite, which moves in the direction reverse rotation planets. 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 .

Space has long attracted people's attention. Astronomers began studying the planets of the Solar System back in the Middle Ages, examining them through primitive telescopes. But a thorough classification and description of the structural features and movements of celestial bodies became possible only in the 20th century. With the advent of powerful equipment equipped with last word observatory technology and spaceships Several previously unknown objects were discovered. Now every schoolchild can list all the planets of the solar system in order. A space probe has landed on almost all of them, and so far man has only visited the Moon.

What is the Solar System

The Universe is huge and includes many galaxies. Our Solar System is part of a galaxy containing more than 100 billion stars. But there are very few that are like the Sun. Basically, they are all red dwarfs, which are smaller in size and do not shine as brightly. Scientists have suggested that the solar system was formed after the emergence of the Sun. Its huge field of attraction captured a gas-dust cloud, from which, as a result of gradual cooling, particles of solid matter formed. Over time, celestial bodies were formed from them. It is believed that the Sun is now in the middle of its life path, therefore, it, as well as all the celestial bodies dependent on it, will exist for several more billions of years. Near space has been studied by astronomers for a long time, and any person knows what planets of the solar system exist. Photos of them taken from space satellites can be found on the pages of various information resources devoted to this topic. All celestial bodies are held strong field gravity of the Sun, which makes up more than 99% of the volume of the solar system. Large celestial bodies rotate around the star and around its axis in one direction and in one plane, which is called the ecliptic plane.

Planets of the Solar System in order

In modern astronomy, it is customary to consider celestial bodies starting from the Sun. In the 20th century, a classification was created that includes 9 planets of the solar system. But recent space exploration and newest discoveries prompted scientists to revise many provisions in astronomy. And in 2006, at an international congress, due to its small size (a dwarf with a diameter not exceeding three thousand km), Pluto was excluded from the number of classical planets, and there were eight of them left. Now the structure of our solar system has taken on a symmetrical, slender appearance. It includes the four terrestrial planets: Mercury, Venus, Earth and Mars, then comes the asteroid belt, followed by the four giant planets: Jupiter, Saturn, Uranus and Neptune. On the outskirts of the solar system there is also a space that scientists call the Kuiper Belt. This is where Pluto is located. These places are still little studied due to their remoteness from the Sun.

Features of the terrestrial planets

What allows us to classify these celestial bodies as one group? Let us list the main characteristics of the inner planets:

• relatively small size;
• hard surface, high density and similar composition (oxygen, silicon, aluminum, iron, magnesium and other heavy elements);
• presence of atmosphere;
• identical structure: a core of iron with nickel impurities, a mantle consisting of silicates, and a crust of silicate rocks (except for Mercury - it has no crust);
• a small number of satellites - only 3 for four planets;
• rather weak magnetic field.

Features of the giant planets

As for the outer planets, or gas giants, they have the following similar characteristics:

• large sizes and weights;
• they do not have a solid surface and consist of gases, mainly helium and hydrogen (therefore they are also called gas giants);
• liquid core consisting of metallic hydrogen;
• high rotation speed;
• a strong magnetic field, which explains the unusual nature of many processes occurring on them;
• there are 98 satellites in this group, most of which belong to Jupiter;
• The most characteristic feature of gas giants is the presence of rings. All four planets have them, although they are not always noticeable.

The first planet is Mercury

It is located closest to the Sun. Therefore, from its surface the star appears three times larger than from the Earth. This also explains the strong temperature changes: from -180 to +430 degrees. Mercury moves very quickly in its orbit. Maybe that's why it got such a name, because in Greek mythology Mercury is the messenger of the gods. There is practically no atmosphere here and the sky is always black, but the Sun shines very brightly. However, there are places at the poles where its rays never hit. This phenomenon can be explained by the tilt of the rotation axis. No water was found on the surface. This circumstance, as well as the abnormally high daytime temperature (as well as the low nighttime temperature) fully explain the fact of the absence of life on the planet.

Venus

If you study the planets of the solar system in order, then Venus comes second. People could observe it in the sky back in ancient times, but since it was shown only in the morning and evening, it was believed that these were 2 different objects. By the way, our Slavic ancestors called it Mertsana. It is the third brightest object in our solar system. People used to call it the morning and evening star, because it is best visible before sunrise and sunset. Venus and Earth are very similar in structure, composition, size and gravity. This planet moves very slowly around its axis, making a full revolution in 243.02 Earth days. Of course, conditions on Venus are very different from those on Earth. It is twice as close to the Sun, so it is very hot there. The high temperature is also explained by the fact that thick clouds of sulfuric acid and an atmosphere of carbon dioxide create a greenhouse effect on the planet. In addition, the pressure at the surface is 95 times greater than on Earth. Therefore, the first ship that visited Venus in the 70s of the 20th century stayed there for no more than an hour. Another peculiarity of the planet is that it rotates in the opposite direction compared to most planets. Astronomers still know nothing more about this celestial object.

Third planet from the Sun

The only place in the Solar System, and indeed in the entire Universe known to astronomers, where life exists is Earth. IN earth group it has the largest dimensions. What else are her

1. The highest gravity among the terrestrial planets.
2. Very strong magnetic field.
3. High density.
4. It is the only one among all the planets that has a hydrosphere, which contributed to the formation of life.
5. It has the largest satellite compared to its size, which stabilizes its tilt relative to the Sun and influences natural processes.

The planet Mars

This is one of the smallest planets in our Galaxy. If we consider the planets of the solar system in order, then Mars is the fourth from the Sun. Its atmosphere is very rarefied, and the pressure on the surface is almost 200 times less than on Earth. For the same reason, very strong temperature changes are observed. The planet Mars has been little studied, although it has long attracted the attention of people. According to scientists, this is the only celestial body on which life could exist. After all, in the past there was water on the surface of the planet. This conclusion can be drawn from the fact that there are large ice caps at the poles, and the surface is covered with many grooves, which could be dried up river beds. In addition, there are some minerals on Mars that can only be formed in the presence of water. Another feature of the fourth planet is the presence of two satellites. What makes them unusual is that Phobos gradually slows down its rotation and approaches the planet, while Deimos, on the contrary, moves away.

What is Jupiter famous for?

The fifth planet is the largest. The volume of Jupiter would fit 1300 Earths, and its mass is 317 times that of Earth. Like all gas giants, its structure is hydrogen-helium, reminiscent of the composition of stars. Jupiter is the most interesting planet, which has many characteristic features:

• it is the third brightest celestial body after the Moon and Venus;
• Jupiter has the strongest magnetic field of any planet;
• it completes a full revolution around its axis in just 10 Earth hours - faster than other planets;
• An interesting feature of Jupiter is the large red spot - this is how an atmospheric vortex rotating counterclockwise is visible from Earth;
• like all giant planets, it has rings, although not as bright as Saturn’s;
• this planet has the largest number of satellites. He has 63 of them. The most famous are Europa, on which water was found, Ganymede - the largest satellite of the planet Jupiter, as well as Io and Calisto;
• Another feature of the planet is that in the shadow the surface temperature is higher than in places illuminated by the Sun.

Planet Saturn

It is the second largest gas giant, also named after the ancient god. It is composed of hydrogen and helium, but traces of methane, ammonia and water have been found on its surface. Scientists have found that Saturn is the rarest planet. Its density is less than that of water. This gas giant rotates very quickly - it makes one revolution in 10 Earth hours, as a result of which the planet is flattened from the sides. Huge speeds on Saturn and the wind - up to 2000 kilometers per hour. This is faster than the speed of sound. Saturn has another one distinctive feature- it holds 60 satellites in its field of attraction. The largest of them, Titan, is the second largest in the entire solar system. Uniqueness of this object is that, by examining its surface, scientists for the first time discovered a celestial body with conditions similar to those that existed on Earth about 4 billion years ago. But the most main feature Saturn is the presence of bright rings. They circle the planet around the equator and reflect more light than the planet itself. Four is the most amazing phenomenon in the solar system. What's unusual is that the inner rings move faster than the outer rings.

- Uranus

So, we continue to consider the planets of the solar system in order. The seventh planet from the Sun is Uranus. It is the coldest of all - the temperature drops to -224 °C. In addition, scientists did not find metallic hydrogen in its composition, but found modified ice. Therefore, Uranus is classified as a separate category of ice giants. An amazing feature of this celestial body is that it rotates while lying on its side. The change of seasons on the planet is also unusual: winter reigns there for as many as 42 Earth years, and the Sun does not appear at all; summer also lasts 42 years, and the Sun does not set during this time. In spring and autumn, the star appears every 9 hours. Like all giant planets, Uranus has rings and many satellites. As many as 13 rings revolve around it, but they are not as bright as those of Saturn, and the planet contains only 27 satellites. If we compare Uranus with the Earth, then it is 4 times larger than it, 14 times heavier and is located at a distance from the Sun of 19 times the path to the star from our planet.

Neptune: the invisible planet

After Pluto was excluded from the number of planets, Neptune became the last from the Sun in the system. It is located 30 times further from the star than the Earth, and is not visible from our planet even with a telescope. Scientists discovered it, so to speak, by accident: observing the peculiarities of the movement of the planets closest to it and their satellites, they concluded that there must be another large celestial body beyond the orbit of Uranus. After discovery and research it became clear interesting features of this planet:

• due to the presence of a large amount of methane in the atmosphere, the color of the planet from space appears blue-green;
• Neptune's orbit is almost perfectly circular;
• the planet rotates very slowly - it makes one circle every 165 years;
• Neptune is 4 times larger than Earth and 17 times heavier, but the force of gravity is almost the same as on our planet;
• the largest of the 13 satellites of this giant is Triton. It is always turned to the planet with one side and slowly approaches it. Based on these signs, scientists suggested that it was captured by the gravity of Neptune.

There are about one hundred billion planets in the entire Milky Way galaxy. So far, scientists cannot study even some of them. But the number of planets in the solar system is known to almost all people on Earth. True, in the 21st century, interest in astronomy has faded a little, but even children know the names of the planets of the solar system.