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Astronomy of the planet of the solar system. Planets of the Solar System in order

PLANETS

In ancient times, people knew only five planets: Mercury, Venus, Mars, Jupiter and Saturn, the only ones that can be seen with the naked eye.
Uranus, Neptune and Pluto were discovered using telescopes in 1781, 1846 and 1930. Long time Astronomers studied the planets by observing them from Earth. They determined that all the planets, except Pluto, move in circular orbits in the same plane and in the same direction, calculated the sizes of the planets and the distances from them to the Sun, formed their idea of the structure of the planets, and even assumed that Venus and Mars could be similar Earth, and there may be life on them.

The launch of automatic space stations to the planets made it possible to significantly expand, and in many ways revise, ideas about the planets: it became possible to see photographs of the surface, explore the soil and atmosphere of the planets.

Mercury.

Mercury is a small planet, a little larger than the moon. Its surface is also dotted with craters from collisions with meteorites. No geological processes have erased these dents from his face. Mercury is cold inside. It moves around the Sun faster than other planets, but around its axis very slowly. Having circled the Sun twice, Mercury only has time to turn around its axis three times. Because of this, the temperature is sunny side the temperature of the planet exceeds 300 degrees, and on the unlit surface darkness and severe cold reign. Mercury has virtually no atmosphere.

Venus.

Exploring Venus is not easy. It is shrouded in a thick layer of clouds, and under this serene exterior hides a real hell, the pressure is a hundred times higher than on Earth, the temperature on the surface is about 500 degrees, which is caused by “ greenhouse effect" The Soviet automatic station “Venera - 9” for the first time managed to transmit to Earth images of a surface filled with lava and covered with stones. In the conditions of Venus, the apparatus lowered to the surface of the planet quickly breaks down, so American scientists decided to obtain data on the planet’s topography in a different way.

The Magellan robotic probe, having flown around Venus many times, probed the planet with radar, resulting in a comprehensive picture of the surface. In some places, the relief of Venus is similar to that of Earth, but mostly the landscapes are strange: high mountainous round areas surrounded by mountain ranges 250 - 300 km in diameter, the entire area of which is occupied by volcanoes; other volcanic formations resemble cakes with steep edges and a flat top. The surface of the planet is cut by channels laid by lava. Traces of active volcanic activity are visible everywhere. Meteor craters on the surface of Venus are distributed evenly, which means that its surface took shape at the same time. Scientists cannot explain how this could happen; Venus seemed to boil and be flooded with lava. Now volcanic activity is not detected on the planet.

The atmosphere of Venus is not at all similar to that of Earth; it mainly consists of carbon dioxide. The thickness of the gas shell of Venus, compared to the earth's, is monstrously large. The cloud layer reaches 20 km. The presence of concentrated aqueous solution sulfuric acid. Sunlight does not reach the surface of Venus, twilight reigns there, sulfur rain falls, and the landscape is constantly illuminated by flashes of lightning. High in the atmosphere of the planet, constant winds rage, which drive clouds with enormous speed, the upper layer of the Venusian atmosphere makes full turn around the planet within four Earth days. Solid Venus, on the contrary, rotates around its axis very slowly and in a different direction than all the other planets. Venus has no satellites.

Mars.

In the 20th century, the planet Mars was chosen by science fiction writers; in their novels, the Martian civilization was incomparably higher than the earthly one. The mysterious, inaccessible Mars began to reveal its secrets when Soviet and American automatic spacecraft began to be sent to study it.

The Mariner 9 station, orbiting Mars, took photographs of all parts of the planet, which made it possible to create detailed map surface relief. Researchers have discovered traces of active geological processes on the planet: huge volcanoes, the largest of them, Olympus Mons, 25 km high, and a huge fracture of the Martian crust, called Valles Marineris, which crosses an eighth of the planet.

Gigantic structures grew in the same place for billions of years, unlike the Earth with its drifting continents, the surface of Mars did not move. The geological structures of the Earth, compared to those on Mars, are dwarfs. Are volcanoes active on Mars now? Scientists believe that geological activity on the planet is obviously a thing of the past.

Martian landscapes are dominated by reddish rocky deserts. Light transparent clouds float above them in the pink sky. The sky turns blue at sunset. The atmosphere of Mars is very thin. Every few years there are dust storms that cover almost the entire surface of the planet. A day on Mars lasts 24 hours 37 minutes, the inclination of the axis of rotation of Mars to the orbital plane is almost the same as that of the Earth, so the change of seasons on Mars is quite consistent with the change of seasons on Earth. The planet is poorly heated by the Sun, so its surface temperature even on a summer day does not exceed 0 degrees, and in winter time From the severe cold, frozen carbon dioxide settles on the stones, and the Polar caps are mainly made of it. No traces of life have yet been found.

From Earth, Mars is visible as a reddish star, which is probably why it bears the name of the god of war, Mars. His two companions were named Phobos and Deimos, which translated from ancient Greek means “fear” and “horror.” Satellites of Mars - space "rocks" irregular shape. Phobos measures 18km x 22km, and Deimos measures 10km x 16km.

The planets are giants.

In 1977, American scientists and engineers launched an automatic interplanetary station towards Jupiter as part of the Voyager program. Once every 175 years, Jupiter, Saturn, Neptune and Pluto are positioned in such a way relative to the Earth that the launched spacecraft can explore all these planets in one flight. Scientists have calculated that, under certain conditions, a spacecraft, approaching a planet, falls into a gravitational slingshot, and the planet itself sends the apparatus further to another planet. The calculations turned out to be correct. Earthlings were able to see these distant planets and their satellites through the “eyes” of space robots, and unique information was transmitted to Earth.

Jupiter.

Jupiter is the most big planet in the solar system. It does not have a solid surface and consists mainly of hydrogen and helium. Due to the high speed of rotation around its axis, it is noticeably compressed at the poles. Jupiter has a huge magnetic field; if it became visible, it would look the size of the solar disk from Earth.

In the photographs, scientists were able to see only clouds in the planet’s atmosphere, which create stripes parallel to the equator. But they moved with great speed, bizarrely changing their shape. Numerous vortices, auroras and lightning flashes were recorded in the cloud cover of Jupiter. On the planet, wind speeds reach one hundred kilometers per hour. The most amazing formation in the atmosphere of Jupiter is a large red spot 3 times the size of the Earth. Astronomers have observed it since the 17th century. It is possible that this is the tip of a gigantic tornado. Jupiter releases more energy than it receives from the Sun. Scientists believe that in the center of the planet, gases are compressed to the state of a metallic liquid. This hot core is the power plant that generates winds and a monstrous magnetic field.

But the main surprises for scientists were not presented by Jupiter itself, but by its satellites.

Satellites of Jupiter.

There are 16 known satellites of Jupiter. The largest of them, Io, Europa, Callisto and Ganymede, were discovered by Galileo; they are visible even with strong binoculars. It was believed that the satellites of all planets are similar to the Moon - they are cold and lifeless. But Jupiter's moons surprised researchers.

And about- the size of the Moon, but it is the first celestial body other than Earth on which active volcanoes have been discovered. Io is completely covered in volcanoes. Its surface is washed by multi-colored lava flows, volcanoes emit sulfur. But what is the reason for the active volcanic activity of such a small cosmic body? Revolving around the huge Jupiter, Io either approaches it or moves away.

Under the influence of either increasing or decreasing gravitational force, Io either contracts or expands. Friction forces heated its inner layers to enormous temperatures. Io's volcanic activity is incredible, its surface changing before our eyes. Io moves in Jupiter's powerful magnetic field, so it accumulates a huge electric charge, which discharges onto Jupiter in the form of a continuous stream of lightning, causing storms on the planet.

Europe has a relatively smooth surface, virtually without relief. It is covered with a layer of ice, and it is likely that the ocean is hidden underneath it. Instead of molten rocks, water oozes from cracks here. This is a completely new type of geological activity.

Ganymede- the largest satellite in the solar system. Its size is almost the same as that of Mercury.

Callisto dark and cold, its surface, pockmarked with meteorite craters, has not changed for billions of years.

Saturn.

Saturn, like Jupiter, does not have a solid surface - it is a gas giant planet. It also consists of hydrogen and helium, but it is cooler, since it produces less heat itself and receives less of it from the Sun. But on Saturn the winds are faster than on Jupiter. Stripes, vortices and other formations are observed in the atmosphere of Saturn, but they are short-lived and irregular.

Naturally, scientists' attention was directed to the rings that surround the planet's equator. They were discovered by astronomers back in the 17th century, and since then scientists have been trying to understand what they are. Photos of rings transmitted to the ground automatically space station, surprised the researchers. They were able to identify several hundred rings nested inside one another, some intertwined with each other, dark stripes were found on the rings that appeared and disappeared, they were called knitting needles. Scientists were able to see the rings of Saturn from a fairly close distance, but they had more questions than answers.

In addition to the rings, 15 satellites move around Saturn. The largest of them is Titan, slightly smaller than Mercury. Titan's dense atmosphere is much thicker than Earth's and consists almost entirely of nitrogen; it did not allow us to see the surface of the satellite, but scientists suggest that the internal structure of Titan is similar to the structure of the Earth. The temperature at its surface is below minus 200 degrees.

Uranus.

Uranus differs from all other planets in that its axis of rotation lies almost in the plane of its orbit, all planets look like a toy top, and Uranus rotates as if “lying on its side.” Voyager was able to “see” little in the atmosphere of Uranus; the planet turned out to be very monotonous in appearance. There are 5 satellites orbiting Uranus.

Neptune.

It took Voyager 12 years to get to Neptune. How surprised the scientists were when, on the outskirts of the solar system, they saw a planet very similar to Earth. It was a deep blue color, with white clouds moving in different directions in the atmosphere. The winds on Neptune blow much stronger than on other planets.

There is so little energy on Neptune that the wind, once it picks up, cannot stop. Scientists have discovered a system of rings around Neptune, but they are incomplete and represent arcs; there is no explanation for this yet. Neptune and Uranus are also giant planets, but not gas, but ice.

Neptune has 3 satellites. One of them is that Triton rotates in the direction opposite to the direction of rotation of Neptune itself. Perhaps it did not form in Neptune's gravitational zone, but was pulled toward the planet when it came close to it and fell into its gravitational zone. Triton is the coldest body in the solar system, its surface temperature is slightly higher absolute zero(minus 273 degrees). But nitrogen geysers were discovered on Triton, which indicates its geological activity.

Pluto

Now Pluto is officially no longer a planet. It should now be considered a "dwarf planet", one of three in the Solar System. Pluto's fate was determined in 2006 by a vote of members of the International Astronomical Society in Prague.

To avoid confusion and map clutter solar system, The International Astronomical Union has prescribed that sufficiently large celestial bodies that are not among the eight previously identified planets be classified as dwarf planets. In particular, Pluto, Charon ( former companion Pluto), the asteroid Ceres, orbiting between the orbits of Mars and Jupiter, as well as the so-called Kuiper belt objects Xena (object UB313) and Sedna (object 90377).

Hello, dear readers of the blog site. The solar system is a collection of planets revolving around the Sun in orbits, the Sun and a number of other celestial bodies of smaller sizes.

The composition includes only natural objects orbiting a star or a planet. Of course, satellites launched from Earth are not one of them.

But let's take a closer look at what the solar system is and what its structure is. Let's find out what small and large bodies form it. Which is the largest planet and which is the smallest. Let's list them all in order, look at it and its layouts.

Planets of the solar system

You can read about the sun itself (the central star of the system) at the link above or briefly read the information on it at the bottom of this article. From interesting facts we can add that the mass of the sun makes up 99.86% of the mass of the entire solar system, which indicates its undeniable importance.

How many planets are in the solar system and their order

The next largest bodies after the Sun are the planets. How many planets are there in the solar system? Until recently, it was believed that 9 planets revolve around our star:

There are special models or drawings of the solar system for children to help them understand what it means to revolve around the Sun, such as the model shown above.

The largest and smallest planet in the solar system

Is Pluto a planet or not anymore?

Pluto recognized as the smallest planet in the solar system. However, in Lately Many questions arose about whether it was correct to consider Pluto a planet. Why? Here are some facts that were given reason to doubt whether this object can be called a planet:

The mass of Pluto is less than the mass of the Moon, the Earth's satellite. It is not enough for Pluto to clear the space in its orbit from other bodies. The orbit of Pluto is populated by many objects that have the same composition.
Discovery of a body beyond the orbit of Pluto that has a large mass and. This object was named Eris.
The center of mass of the Pluto-Charon system (Charon is a satellite) lies outside these two bodies.

Much has become clear after detailed studies of the Kuiper belt. It consists of many ice objects with a diameter of 100 km. Pluto itself has a diameter of 2400 km.

After a series of similar discoveries, astronomers faced the task of redefining the concept of planet.

One of the requirements was that the planet must be able to clear the space around your orbit. This is precisely the reason why Pluto was excluded from the list of planets and given the name of a dwarf planet.

Terrestrial planets including the smallest

The planets of the solar system rotate in orbits. The first 4 planets of the solar system are generalized as the terrestrial group:

Mercury - this is the smallest and the planet closest to the star. The period of its rotation around the star takes 88 days.
Venus. It rotates around its axis in the opposite direction relative to its orbital motion. Another such planet is Uranus. Venus is the most hot planet. The atmospheric temperature reaches +470°C.
Earth is the third planet in the solar system from the Sun. It has the highest density and diameter in its group. There is free oxygen in the atmosphere here. Earth has one natural satellite- The moon.
Mars. The atmosphere of the fourth planet consists of carbon dioxide. Due to the presence of iron oxide in the soil, the planet has a reddish tint.

Giant planets including the largest

Behind four planets terrestrial group followed by the giant planets of the solar system:

Jupiter - largest planet. Its mass is 318 times the mass of our planet. It consists of H (hydrogen) and He (helium), and has many satellites, one of which is larger in size even than Mercury.
Saturn. He is known to us for his rings. The planet has many satellites.
Uranus. This planet has the smallest mass among the giants. It differs in that the angle of inclination of its axis to the plane is almost 100°. Therefore, we can say about this planet that it does not so much rotate as it rolls along its orbit.
Neptune. The rotation period is 248 years. It is the last planet, but far from the last body in the solar system.

The photo above shows the planets of the solar system and the actual ratio of their sizes.

Small bodies of the Solar System

These are small bodies orbiting our star. Most often they do not have a spherical shape, but look like blocks of stone. They have no atmosphere. Asteroids may have satellites. They are not included in the solar system model.

After the orbit of the fourth planet is the asteroid belt. It ends before the orbit of the fifth planet - Jupiter. Asteroids are the most common small bodies in the solar system. Their sizes can vary from several meters to hundreds of kilometers. Although they are much smaller than planets, such bodies can have satellites.

Besides the asteroid belt, there are other asteroids. The paths of some of these bodies intersect with the orbit of our planet. However, we do not have to worry that the movement of the asteroid will disturb the arrangement of the planets in the solar system.

Dwarf planets

A number of asteroids that have a large mass and diameter have come to be classified as dwarf planets. Among them:

Ceres.
Pluto (formerly considered a planet).
Eris (located behind Pluto).

It is a celestial luminous object with a distinct head and tail. The brightness of a comet directly depends on its distance from the Sun.

The comet consists of the following parts:

Core. It contains almost the entire weight of the comet.
Coma is a foggy membrane located around the nucleus.
Tail. It is located in the opposite direction from the Sun.

One of the famous comets is Halley's comet. It either approaches the Sun or moves away from it. The comet's head consists of frozen water, metal particles and various compounds. The diameter of the nucleus of this comet is 10 km. The period of passage of the orbit (ellipse) is about 75 years.

The point in the orbit at which the body is as close as possible to the Star is called perihelion, and the opposite (farthest) is called aphelion.

Meteorites

These are relatively small bodies that fall onto the surface of other larger celestial objects. can be iron, stone or iron-stone. About 2,000 tons of meteorites fall onto the surface of our planet per year. Some have a mass of several grams, while others weigh several tens of tons. For example, the Tunguska meteorite that fell to Earth in 1908 knocked down forests.

Research into our solar system will continue for many years, so surely in the future we will become aware of more and more new facts and information about planets, comets, asteroids and other cosmic bodies.

The Sun is a star in the solar system

, located in the center of our system and which is the basis of the layout of the solar system. Its mass is 1,989 ∙ 10 30 kg, which occupies 99.86% of the mass of the system. The diameter of the star is 1.391 million km. It is a fiery gas ball. Thanks to the processes occurring in the core, a huge amount of energy is released.

The Sun belongs to a group of stars called “yellow dwarfs.” Yellow stars are those whose surface temperatures range from 5000 to 7500 K.

Structure of the Sun

When considering the structure of the Solar System, it is worth starting from its center, namely the center of the Sun. The luminary can be divided into several layers:

Core. In the depths, hydrogen atoms rupture, which is accompanied by the release of enormous energy. There, protons and neutrons also fuse into the nuclei of helium atoms. In the core the temperature reaches 15 million K, which is 2.5 times higher than on the surface. The core extends 173 thousand km from the center of the Sun, which is about 20% of the radius of the star.
Radiation zone. In it, photons emitted by the nucleus wander for about 200 thousand years and lose their energy due to collisions with plasma particles.
Convective zone. It is similar to a boiling mass in which particles located on the border of the radiation and convective zones constantly rise to the surface. Here, the path of particles to the surface of the star takes much less time than the duration of the processes in the radiation zone. The convective zone extends from 70% and almost to the surface of the star.
Photosphere. It is extremely thin - only 100 km (compared to the size of the Sun - this is really not much). This visible surface luminaries
The chromosphere is a heterogeneous layer solar atmosphere, which is located directly above the photosphere. Here the temperature increases from 6,000 K to 20,000 K.
The corona is the outer layer of the atmosphere. Due to the fact that its brightness is much less than that of the star, the corona is not visible to the naked eye (without additional equipment it is visible only during eclipses). The temperature here is the highest in the entire solar system - 1,000,000 K.

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Planets in the Solar System: types

Location of the terrestrial group in relation to the Sun

The first planet is Mercury, followed by Venus; Next comes our Earth and, finally, Mars.
Terrestrial planets do not have many satellites or moons. Of these four planets, only Earth and Mars have satellites.

Planets that belong to the terrestrial group are highly dense and consist of metal or stone. Basically, they are small and rotate around their axis. Their rotation speed is also low.

Gas giants

These are the four space objects that are at the greatest distance from the Sun: Jupiter is at No. 5, followed by Saturn, then Uranus and Neptune.

Jupiter and Saturn are impressively sized planets made of hydrogen and helium compounds. The density of gas planets is low. They rotate at high speeds, have satellites and are surrounded by rings of asteroids.
The “ice giants,” which include Uranus and Neptune, are smaller; their atmospheres contain methane and carbon monoxide.

Gas giants have a strong gravitational field, so they can attract many space objects, in contrast to the terrestrial group.

According to scientists, asteroid rings are the remains of moons changed by the gravitational field of the planets.

Dwarf planet

Dwarfs are space objects whose size does not reach the size of a planet, but exceeds the dimensions of an asteroid. There are a great many such objects in the Solar System. They are concentrated in the Kuiper belt region. The satellites of the gas giants are dwarf planets that have left their orbit.

Planets of the Solar System: the process of emergence

According to the cosmic nebula hypothesis, stars are born in clouds of dust and gas, in nebulae.
Due to the force of attraction, substances come together. Under the influence of the concentrated force of gravity, the center of the nebula contracts and stars form. Dust and gases transform into rings. The rings rotate under the influence of gravity, and planetasimals are formed in the whirlpools, which increase in size and attract cosmetic objects to themselves.

Under the influence of gravity, planetesimals are compressed and acquire spherical shapes. The spheres can unite and gradually turn into protoplanets.

There are eight planets within the solar system. They revolve around the Sun. Their location is as follows:
The closest “neighbor” of the Sun is Mercury, followed by Venus, followed by the Earth, then Mars and Jupiter, further from the Sun are Saturn, Uranus and the last one, Neptune.

Quick answer: 8 planets.

The solar system is a planetary system that includes the central star, which is the Sun, as well as all other natural space objects, which in turn revolve around the Sun.

Interestingly, most of the total mass of the solar system is accounted for by itself, while the rest is accounted for by 8 planets. Yes, yes, there are 8 planets in the solar system, and not 9, as some people believe. Why do they think so? One reason is that they mistake the Sun for another planet, but in fact it is the only star included in the solar system. But in reality everything is simpler - Pluto was previously considered a planet, but is now considered a dwarf planet.

Let's begin the review of the planets, starting with the one closest to the Sun.

Mercury

This planet was named after the ancient Roman god of trade - the fleet-footed Mercury. The fact is that it moves much faster than other planets.

Mercury completely revolves around the Sun in 88 Earth days, while the duration of one sidereal day on Mercury is 58.65 Earth days.

Relatively little is known about the planet, and one of the reasons is that Mercury is too close to the Sun.

Venus

Venus is the second so-called inner planet solar system, which was named after the goddess of love Venus. It is worth noting that this is the only planet that received its name in honor of a female deity, rather than a male one.

Venus is very similar to Earth, not only in size, but also in composition and even gravity.

It is believed that Venus once had many oceans similar to the ones we have. However, some time ago the planet heated up so much that all the water evaporated, leaving behind only rocks. Water vapor was carried into outer space.

Earth

The third planet is Earth. It is the largest planet among the terrestrial planets.

It was formed approximately 4.5 billion years ago, after which it was almost immediately joined by its only satellite, which is the Moon. It is believed that life on Earth appeared about 3.9 billion years ago and over time its biosphere began to change into better side, which made it possible to form the ozone layer, increase the growth of aerobic organisms, etc. All this, among other things, allows us to exist now.

Mars

Mars closes the four terrestrial planets. The planet is named after the ancient Roman god of war, Mars. This planet is also called red because its surface has a reddish tint due to iron oxide.

Mars has surface pressure 160 times less than Earth's. On the surface there are craters similar to those that can be seen on the Moon. There are also volcanoes, deserts, valleys and even ice caps.

Mars has two satellites: Deimos and Phobos.

Jupiter

It is the fifth planet from the Sun and the first among the giant planets. By the way, it is the largest in the solar system, which received its name in honor of the ancient Roman supreme god of thunder.

Jupiter has been known for a long time, which is reflected in ancient myths and legends. Has very a large number of satellites - 67 to be exact. Interestingly, some of them were discovered several centuries ago. Thus, Galileo Galilei himself discovered 4 satellites in 1610.

Sometimes Jupiter can be seen with the naked eye, as was the case in 2010.

Saturn

Saturn is the second largest planet in the solar system. It was named after the Roman god of agriculture.

It is known that Saturn consists of hydrogen with signs of water, helium, ammonia, methane and other heavy elements. An unusual wind speed was observed on the planet - about 1800 kilometers per hour.

Saturn has prominent rings that are mostly made of ice, dust, and other elements. Saturn also has 63 satellites, one of which, Titan, is larger than even Mercury.

Uranus

The seventh planet in terms of distance from the Sun. It was discovered relatively recently (in 1781) by William Herschel and was named after the god of the sky.

Uranus is the first planet to be discovered using a telescope, between the Middle Ages and modern times. Interestingly, although the planet can sometimes be seen with the naked eye, before its discovery it was generally believed that it was a dim star.

Uranus has a lot of ice but no metallic hydrogen. The planet's atmosphere is composed of helium and hydrogen, as well as methane.

Uranus has a complex ring system and 27 satellites.

Neptune

Finally, we have reached the eighth and last planet of the solar system. The planet is named after the Roman god of the seas.

Neptune was discovered in 1846, and, interestingly, not through observations, but thanks to mathematical calculations. Initially, only one of its satellites was discovered, although the remaining 13 were not known until the 20th century.

Neptune's atmosphere consists of hydrogen, helium and possibly nitrogen. The most raging here strong winds, the speed of which reaches a fantastic 2100 km/h. In the upper layers of the atmosphere the temperature is about 220°C.

Neptune has a poorly developed ring system.

The solar system is the central star, the Sun, and all the cosmic bodies that revolve around it.

There are 8 largest celestial bodies, or planets, in the solar system. Our Earth is also a planet. In addition to it, 7 more planets travel around the Sun in space: Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune. The last two can only be observed from Earth through a telescope. The rest are visible to the naked eye.

More recently, another celestial body, Pluto, was considered a planet. It is located very far from the Sun, beyond the orbit of Neptune, and was discovered only in 1930. However, in 2006, astronomers introduced a new definition of a classical planet, and Pluto did not fall under it.

The planets have been known to people since ancient times. The closest neighbors of the Earth are Venus and Mars, the farthest from it are Uranus and Neptune.

Large planets are usually divided into two groups. The first group includes the planets closest to the Sun: these are terrestrial planets, or inner planets, - Mercury, Venus, Earth and Mars. All of these planets have a high density and a solid surface (although there is a liquid core underneath). The largest planet in this group is Earth. However, the planets farthest from the Sun - Jupiter, Saturn, Uranus and Neptune - are significantly larger than the Earth. That's why they got the name giant planets. They are also called outer planets. Thus, the mass of Jupiter exceeds the mass of the Earth by more than 300 times. Giant planets differ significantly from the terrestrial planets in their structure: they do not consist of heavy elements, but of gas, mainly hydrogen and helium, like the Sun and other stars. Giant planets do not have a solid surface - they are just balls of gas. That's why they are also called gas planets.

Between Mars and Jupiter there is a belt asteroids, or minor planets. An asteroid is a small planet-like body in the Solar System, ranging in size from a few meters to a thousand kilometers. The largest asteroids in this belt are Ceres, Pallas and Juno.

Beyond the orbit of Neptune there is another belt of small celestial bodies, which is called the Kuiper belt. It is 20 times wider than the asteroid belt. Pluto, which lost its planetary status and was classified as dwarf planets, is just in this belt. There are other dwarf planets in the Kuiper belt that are similar to Pluto, and in 2008 they were named as such - plutoids. These are Makemake and Haumea. By the way, Ceres from the asteroid belt is also classified as dwarf planets(but not plutoids!).

Another plutoid - Eris - is comparable in size to Pluto, but is located much further from the Sun - beyond the Kuiper belt. Interestingly, Eris was at one time even a candidate for the role of the 10th planet in the solar system. But as a result, it was the discovery of Eris that caused a revision of the status of Pluto in 2006, when the International Astronomical Union (IAU) introduced a new classification of celestial bodies of the Solar System. According to this classification, Eris and Pluto did not fall under the concept of a classical planet, but “earned” only the title of dwarf planets - celestial bodies that revolve around the Sun, are not satellites of planets and have a large enough mass to maintain an almost round shape, but, unlike planets, they are not able to clear their orbit from other space objects.

The solar system, in addition to the planets, includes their satellites that revolve around them. There are currently 415 satellites in total. The Earth's constant satellite is the Moon. Mars has 2 satellites - Phobos and Deimos. Jupiter has 67 satellites, and Saturn has 62. Uranus has 27 satellites. And only Venus and Mercury do not have satellites. But the “dwarfs” Pluto and Eris have satellites: Pluto has Charon, and Eris has Dysnomia. However, astronomers have not yet come to a final conclusion whether Charon is a satellite of Pluto or the Pluto-Charon system is a so-called double planet. Even some asteroids have satellites. The champion in size among satellites is Ganymede, a satellite of Jupiter; Saturn's satellite Titan is not far behind it. Both Ganymede and Titan are larger than Mercury.

In addition to planets and satellites, the solar system is crisscrossed by tens, or even hundreds of thousands of different small bodies: tailed celestial bodies - comets, a huge number of meteorites, particles of gas and dust matter, scattered atoms of various chemical elements, flows of atomic particles and others.

All objects of the Solar system are held in it due to the gravitational force of the Sun, and they all rotate around it, moreover, in the same direction with the rotation of the Sun itself and practically in the same plane, which is called plane of the ecliptic. The exception is some comets and Kuiper belt objects. In addition, almost all objects of the Solar system rotate around their own axis, and in the same direction as around the Sun (the exception is Venus and Uranus; the latter even rotates “lying on its side”).

The planets of the solar system revolve around the sun in one plane - the ecliptic plane

Pluto's orbit is highly inclined relative to the ecliptic (17°) and highly elongated

Almost the entire mass of the solar system is concentrated in the Sun - 99.8%. The four largest objects - the gas giants - account for 99% of the remaining mass (with Jupiter and Saturn accounting for the majority - about 90%). As for the size of the solar system, astronomers have not yet reached a consensus on this issue. By modern estimates, the size of the solar system is at least 60 billion kilometers. To at least approximately imagine the scale of the solar system, let us give a more clear example. Within the Solar System, the unit of distance is taken to be the astronomical unit (AU) - the average distance from the Earth to the Sun. It is approximately 150 million km (light travels this distance in 8 minutes 19 seconds). The outer limit of the Kuiper Belt is located at a distance of 55 AU. e. from the Sun.

Another way to imagine the actual size of the solar system is to imagine a model in which all dimensions and distances are reduced to a billion times . In this case, the Earth would be about 1.3 cm in diameter (the size of a grape). The moon will rotate at a distance of about 30 cm from it. The sun will be 1.5 meters in diameter (about the height of a person) and located 150 meters from the Earth (about a city block). Jupiter is 15 cm in diameter (the size of a large grapefruit) and 5 city blocks away from the Sun. Saturn (the size of an orange) is 10 blocks away. Uranus and Neptune (lemons) - 20 and 30 quarters. A person on this scale would be the size of an atom; and the nearest star is 40,000 km away.