Planets of the Solar System

According to the official position of the International Astronomical Union (IAU), the organization that assigns names to astronomical objects, there are only 8 planets.

Pluto was removed from the planet category in 2006. because There are objects in the Kuiper belt that are larger/equal in size to Pluto. Therefore, even if we take it as a full-fledged celestial body, then it is necessary to add Eris to this category, which has almost the same size as Pluto.

By MAC definition, there are 8 known planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

All planets are divided into two categories depending on their physical characteristics: terrestrial planets and gas giants.

Schematic representation of the location of the planets

Terrestrial planets

Mercury

The smallest planet in the solar system has a radius of only 2440 km. The period of revolution around the Sun, equated to an earthly year for ease of understanding, is 88 days, while Mercury manages to rotate around its own axis only one and a half times. Thus, his day lasts approximately 59 Earth days. For a long time it was believed that this planet always turned the same side to the Sun, since periods of its visibility from Earth were repeated with a frequency approximately equal to four Mercury days. This misconception was dispelled with the advent of the ability to use radar research and conduct continuous observations using space stations. The orbit of Mercury is one of the most unstable; not only the speed of movement and its distance from the Sun change, but also the position itself. Anyone interested can observe this effect.

Mercury in color, image from the MESSENGER spacecraft

Its proximity to the Sun is the reason why Mercury is subject to the largest temperature changes among the planets in our system. The average daytime temperature is about 350 degrees Celsius, and the nighttime temperature is -170 °C. Sodium, oxygen, helium, potassium, hydrogen and argon were detected in the atmosphere. There is a theory that it was previously a satellite of Venus, but so far this remains unproven. It does not have its own satellites.

Venus

The second planet from the Sun, the atmosphere is almost entirely composed of carbon dioxide. It is often called the Morning Star and the Evening Star, because it is the first of the stars to become visible after sunset, just as before dawn it continues to be visible even when all the other stars have disappeared from view. The percentage of carbon dioxide in the atmosphere is 96%, there is relatively little nitrogen in it - almost 4%, and water vapor and oxygen are present in very small quantities.

Venus in the UV spectrum

Such an atmosphere creates a greenhouse effect; the temperature on the surface is even higher than that of Mercury and reaches 475 °C. Considered the slowest, a Venusian day lasts 243 Earth days, which is almost equal to a year on Venus - 225 Earth days. Many call it Earth's sister because of its mass and radius, the values ​​of which are very close to those of Earth. The radius of Venus is 6052 km (0.85% of Earth's). Like Mercury, there are no satellites.

The third planet from the Sun and the only one in our system where there is liquid water on the surface, without which life on the planet could not have developed. At least life as we know it. The radius of the Earth is 6371 km and, unlike other celestial bodies in our system, more than 70% of its surface is covered with water. The rest of the space is occupied by continents. Another feature of the Earth is the tectonic plates hidden under the planet's mantle. At the same time, they are able to move, albeit at a very low speed, which over time causes changes in the landscape. The speed of the planet moving along it is 29-30 km/sec.

Our planet from space

One revolution around its axis takes almost 24 hours, and a complete passage through the orbit lasts 365 days, which is much longer in comparison with its closest neighboring planets. The Earth's day and year are also accepted as a standard, but this is done only for the convenience of perceiving time periods on other planets. The Earth has one natural satellite - the Moon.

Mars

The fourth planet from the Sun, known for its thin atmosphere. Since 1960, Mars has been actively explored by scientists from several countries, including the USSR and the USA. Not all exploration programs have been successful, but water found at some sites suggests that primitive life exists on Mars, or existed in the past.

The brightness of this planet allows it to be seen from Earth without any instruments. Moreover, once every 15-17 years, during the Confrontation, it becomes the brightest object in the sky, eclipsing even Jupiter and Venus.

The radius is almost half that of Earth and is 3390 km, but the year is much longer - 687 days. He has 2 satellites - Phobos and Deimos .

Visual model of the solar system

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  • Sun

    The Sun is a star, which is a hot ball of hot gases at the center of our Solar System. Its influence extends far beyond the orbits of Neptune and Pluto. Without the Sun and its intense energy and heat, there would be no life on Earth. There are billions of stars like our Sun scattered throughout the Milky Way galaxy.

  • Mercury

    Sun-scorched Mercury is only slightly larger than Earth's satellite the Moon. Like the Moon, Mercury is practically devoid of an atmosphere and cannot smooth out the traces of impact from falling meteorites, so it, like the Moon, is covered with craters. The day side of Mercury gets very hot from the Sun, while on the night side the temperature drops hundreds of degrees below zero. There is ice in the craters of Mercury, which are located at the poles. Mercury completes one revolution around the Sun every 88 days.

  • Venus

    Venus is a world of monstrous heat (even more than on Mercury) and volcanic activity. Similar in structure and size to Earth, Venus is covered by a thick and toxic atmosphere that creates a strong greenhouse effect. This scorched world is hot enough to melt lead. Radar images through the powerful atmosphere revealed volcanoes and deformed mountains. Venus rotates in the opposite direction from the rotation of most planets.

  • Earth is an ocean planet. Our home, with its abundance of water and life, makes it unique in our solar system. Other planets, including several moons, also have ice deposits, atmospheres, seasons and even weather, but only on Earth did all these components come together in a way that made life possible.

  • Mars

    Although details of the surface of Mars are difficult to see from Earth, observations through a telescope indicate that Mars has seasons and white spots at the poles. For decades, people believed that the bright and dark areas on Mars were patches of vegetation, that Mars might be a suitable place for life, and that water existed in the polar ice caps. When the Mariner 4 spacecraft arrived at Mars in 1965, many scientists were shocked to see photographs of the murky, cratered planet. Mars turned out to be a dead planet. More recent missions, however, have revealed that Mars holds many mysteries that remain to be solved.

  • Jupiter

    Jupiter is the most massive planet in our solar system, with four large moons and many small moons. Jupiter forms a kind of miniature solar system. To become a full-fledged star, Jupiter needed to become 80 times more massive.

  • Saturn

    Saturn is the farthest of the five planets known before the invention of the telescope. Like Jupiter, Saturn is composed primarily of hydrogen and helium. Its volume is 755 times greater than that of the Earth. Winds in its atmosphere reach speeds of 500 meters per second. These fast winds, combined with heat rising from the planet's interior, cause the yellow and golden streaks we see in the atmosphere.

  • Uranus

    The first planet found using a telescope, Uranus was discovered in 1781 by astronomer William Herschel. The seventh planet is so far from the Sun that one revolution around the Sun takes 84 years.

  • Neptune

    Distant Neptune rotates almost 4.5 billion kilometers from the Sun. It takes him 165 years to complete one revolution around the Sun. It is invisible to the naked eye due to its vast distance from Earth. Interestingly, its unusual elliptical orbit intersects with the orbit of the dwarf planet Pluto, which is why Pluto is inside the orbit of Neptune for about 20 years out of 248 during which it makes one revolution around the Sun.

  • Pluto

    Tiny, cold and incredibly distant, Pluto was discovered in 1930 and was long considered the ninth planet. But after discoveries of Pluto-like worlds that were even further away, Pluto was reclassified as a dwarf planet in 2006.

Planets are giants

There are four gas giants located beyond the orbit of Mars: Jupiter, Saturn, Uranus, Neptune. They are located in the outer solar system. They are distinguished by their massiveness and gas composition.

Planets of the solar system, not to scale

Jupiter

The fifth planet from the Sun and the largest planet in our system. Its radius is 69912 km, it is 19 times larger than the Earth and only 10 times smaller than the Sun. The year on Jupiter is not the longest in the solar system, lasting 4333 Earth days (less than 12 years). His own day has a duration of about 10 Earth hours. The exact composition of the planet's surface has not yet been determined, but it is known that krypton, argon and xenon are present on Jupiter in much larger quantities than on the Sun.

There is an opinion that one of the four gas giants is actually a failed star. This theory is also supported by the largest number of satellites, of which Jupiter has many - as many as 67. To imagine their behavior in the planet’s orbit, you need a fairly accurate and clear model of the solar system. The largest of them are Callisto, Ganymede, Io and Europa. Moreover, Ganymede is the largest satellite of the planets in the entire solar system, its radius is 2634 km, which is 8% greater than the size of Mercury, the smallest planet in our system. Io has the distinction of being one of only three moons with an atmosphere.

Saturn

The second largest planet and the sixth in the solar system. In comparison with other planets, it is most similar to the Sun in the composition of chemical elements. The radius of the surface is 57,350 km, the year is 10,759 days (almost 30 Earth years). A day here lasts a little longer than on Jupiter - 10.5 Earth hours. In terms of the number of satellites, it is not much behind its neighbor - 62 versus 67. The largest satellite of Saturn is Titan, just like Io, which is distinguished by the presence of an atmosphere. Slightly smaller in size, but no less famous are Enceladus, Rhea, Dione, Tethys, Iapetus and Mimas. It is these satellites that are the objects for the most frequent observation, and therefore we can say that they are the most studied in comparison with the others.

For a long time, the rings on Saturn were considered a unique phenomenon unique to it. Only recently it was established that all gas giants have rings, but in others they are not so clearly visible. Their origin has not yet been established, although there are several hypotheses about how they appeared. In addition, it was recently discovered that Rhea, one of the satellites of the sixth planet, also has some kind of rings.

The endless space that surrounds us is not just a huge airless space and emptiness. Here everything is subject to a single and strict order, everything has its own rules and obeys the laws of physics. Everything is in constant motion and is constantly interconnected with each other. This is a system in which each celestial body occupies its specific place. The center of the Universe is surrounded by galaxies, among which is our Milky Way. Our galaxy, in turn, is formed by stars around which large and small planets with their natural satellites revolve. The picture of a universal scale is complemented by wandering objects - comets and asteroids.

Ours is also located in this endless cluster of stars. solar system- a tiny astrophysical object by cosmic standards, which includes our cosmic home - planet Earth. For us earthlings, the size of the solar system is colossal and difficult to perceive. In terms of the scale of the Universe, these are tiny numbers - only 180 astronomical units or 2.693e+10 km. Here, too, everything is subject to its own laws, has its own clearly defined place and sequence.

Brief characteristics and description

The interstellar medium and the stability of the Solar System are ensured by the location of the Sun. Its location is an interstellar cloud included in the Orion-Cygnus arm, which in turn is part of our galaxy. From a scientific point of view, our Sun is located on the periphery, 25 thousand light years from the center of the Milky Way, if we consider the galaxy in the diametrical plane. In turn, the movement of the solar system around the center of our galaxy is carried out in orbit. A complete revolution of the Sun around the center of the Milky Way is carried out in different ways, within 225-250 million years and is one galactic year. The orbit of the Solar System has an inclination of 600 to the galactic plane. Nearby, in the neighborhood of our system, other stars and other solar systems with their large and small planets are running around the center of the galaxy.

The approximate age of the Solar System is 4.5 billion years. Like most objects in the Universe, our star was formed as a result of the Big Bang. The origin of the Solar System is explained by the same laws that operated and continue to operate today in the fields of nuclear physics, thermodynamics and mechanics. First, a star was formed, around which, due to the ongoing centripetal and centrifugal processes, the formation of planets began. The Sun was formed from a dense accumulation of gases - a molecular cloud, which was the product of a colossal Explosion. As a result of centripetal processes, molecules of hydrogen, helium, oxygen, carbon, nitrogen and other elements were compressed into one continuous and dense mass.

The result of grandiose and such large-scale processes was the formation of a protostar, in the structure of which thermonuclear fusion began. We observe this long process, which began much earlier, today, looking at our Sun 4.5 billion years after its formation. The scale of the processes occurring during the formation of a star can be imagined by assessing the density, size and mass of our Sun:

  • density is 1.409 g/cm3;
  • the volume of the Sun is almost the same figure - 1.40927x1027 m3;
  • star mass – 1.9885x1030 kg.

Today our Sun is an ordinary astrophysical object in the Universe, not the smallest star in our galaxy, but far from the largest. The Sun is in its mature age, being not only the center of the solar system, but also the main factor in the emergence and existence of life on our planet.

The final structure of the solar system falls on the same period, with a difference of plus or minus half a billion years. The mass of the entire system, where the Sun interacts with other celestial bodies of the Solar System, is 1.0014 M☉. In other words, all the planets, satellites and asteroids, cosmic dust and particles of gases revolving around the Sun, compared to the mass of our star, are a drop in the bucket.

The way we have an idea of ​​our star and the planets revolving around the Sun is a simplified version. The first mechanical heliocentric model of the solar system with a clock mechanism was presented to the scientific community in 1704. It should be taken into account that the orbits of the planets of the solar system do not all lie in the same plane. They rotate around at a certain angle.

The model of the solar system was created on the basis of a simpler and more ancient mechanism - tellurium, with the help of which the position and movement of the Earth in relation to the Sun was simulated. With the help of tellurium, it was possible to explain the principle of the movement of our planet around the Sun and to calculate the duration of the earth's year.

The simplest model of the solar system is presented in school textbooks, where each of the planets and other celestial bodies occupies a certain place. It should be taken into account that the orbits of all objects revolving around the Sun are located at different angles to the central plane of the Solar System. The planets of the Solar System are located at different distances from the Sun, rotate at different speeds and rotate differently around their own axis.

A map - a diagram of the Solar System - is a drawing where all objects are located in the same plane. In this case, such an image gives an idea only of the sizes of celestial bodies and the distances between them. Thanks to this interpretation, it became possible to understand the location of our planet among other planets, to assess the scale of celestial bodies and to give an idea of ​​the enormous distances that separate us from our celestial neighbors.

Planets and other objects of the solar system

Almost the entire universe is made up of myriads of stars, among which there are large and small solar systems. The presence of a star with its own satellite planets is a common occurrence in space. The laws of physics are the same everywhere and our solar system is no exception.

If you ask the question how many planets there were in the solar system and how many there are today, it is quite difficult to answer unequivocally. Currently, the exact location of 8 major planets is known. In addition, 5 small dwarf planets revolve around the Sun. The existence of a ninth planet is currently disputed in scientific circles.

The entire solar system is divided into groups of planets, which are arranged in the following order:

Terrestrial planets:

  • Mercury;
  • Venus;
  • Mars.

Gas planets - giants:

  • Jupiter;
  • Saturn;
  • Uranus;
  • Neptune.

All planets presented in the list differ in structure and have different astrophysical parameters. Which planet is larger or smaller than the others? The sizes of the planets of the solar system are different. The first four objects, similar in structure to the Earth, have a solid rock surface and are endowed with an atmosphere. Mercury, Venus and Earth are the inner planets. Mars closes this group. Following it are the gas giants: Jupiter, Saturn, Uranus and Neptune - dense, spherical gas formations.

The process of life of the planets of the solar system does not stop for a second. Those planets that we see in the sky today are the arrangement of celestial bodies that the planetary system of our star has at the current moment. The state that existed at the dawn of the formation of the solar system is strikingly different from what has been studied today.

The astrophysical parameters of modern planets are indicated by the table, which also shows the distance of the planets of the Solar System to the Sun.

The existing planets of the solar system are approximately the same age, but there are theories that in the beginning there were more planets. This is evidenced by numerous ancient myths and legends that describe the presence of other astrophysical objects and disasters that led to the death of the planet. This is confirmed by the structure of our star system, where, along with planets, there are objects that are products of violent cosmic cataclysms.

A striking example of such activity is the asteroid belt, located between the orbits of Mars and Jupiter. Objects are concentrated here in a huge number extraterrestrial origin, mainly represented by asteroids and minor planets. It is these irregularly shaped fragments that are considered in human culture to be the remains of the protoplanet Phaeton, which perished billions of years ago as a result of a large-scale cataclysm.

In fact, there is an opinion in scientific circles that the asteroid belt was formed as a result of the destruction of a comet. Astronomers have discovered the presence of water on the large asteroid Themis and on the small planets Ceres and Vesta, which are the largest objects in the asteroid belt. Ice found on the surface of asteroids may indicate the cometary nature of the formation of these cosmic bodies.

Previously one of the major planets, Pluto is not considered a full-fledged planet today.

Pluto, which was previously ranked among the large planets of the solar system, is today reduced to the size of dwarf celestial bodies revolving around the Sun. Pluto, along with Haumea and Makemake, the largest dwarf planets, is located in the Kuiper belt.

These dwarf planets of the solar system are located in the Kuiper belt. The region between the Kuiper belt and the Oort cloud is the most distant from the Sun, but space is not empty there either. In 2005, the most distant celestial body of our solar system, the dwarf planet Eris, was discovered there. The process of exploration of the most distant regions of our solar system continues. The Kuiper Belt and Oort Cloud are hypothetically the border regions of our star system, the visible boundary. This cloud of gas is located at a distance of one light year from the Sun and is the region where comets, the wandering satellites of our star, are born.

Characteristics of the planets of the solar system

The terrestrial group of planets is represented by the planets closest to the Sun - Mercury and Venus. These two cosmic bodies of the solar system, despite the similarity in physical structure with our planet, are a hostile environment for us. Mercury is the smallest planet in our star system and is closest to the Sun. The heat of our star literally incinerates the surface of the planet, practically destroying its atmosphere. The distance from the surface of the planet to the Sun is 57,910,000 km. In size, only 5 thousand km in diameter, Mercury is inferior to most large satellites, which are dominated by Jupiter and Saturn.

Saturn's satellite Titan has a diameter of over 5 thousand km, Jupiter's satellite Ganymede has a diameter of 5265 km. Both satellites are second in size only to Mars.

The very first planet rushes around our star at tremendous speed, making a full revolution around our star in 88 Earth days. It is almost impossible to notice this small and nimble planet in the starry sky due to the close presence of the solar disk. Among the terrestrial planets, it is on Mercury that the largest daily temperature differences are observed. While the surface of the planet facing the Sun heats up to 700 degrees Celsius, the back side of the planet is immersed in universal cold with temperatures up to -200 degrees.

The main difference between Mercury and all the planets of the solar system is its internal structure. Mercury has the largest iron-nickel inner core, which accounts for 83% of the mass of the entire planet. However, even this uncharacteristic quality did not allow Mercury to have its own natural satellites.

Next to Mercury is the closest planet to us - Venus. The distance from Earth to Venus is 38 million km, and it is very similar to our Earth. The planet has almost the same diameter and mass, slightly inferior in these parameters to our planet. However, in all other respects, our neighbor is fundamentally different from our cosmic home. The period of Venus' revolution around the Sun is 116 Earth days, and the planet rotates extremely slowly around its own axis. The average surface temperature of Venus rotating around its axis over 224 Earth days is 447 degrees Celsius.

Like its predecessor, Venus lacks the physical conditions conducive to the existence of known life forms. The planet is surrounded by a dense atmosphere consisting mainly of carbon dioxide and nitrogen. Both Mercury and Venus are the only planets in the solar system that do not have natural satellites.

Earth is the last of the inner planets of the solar system, located at a distance of approximately 150 million km from the Sun. Our planet makes one revolution around the Sun every 365 days. Rotates around its own axis in 23.94 hours. The Earth is the first of the celestial bodies located on the path from the Sun to the periphery, which has a natural satellite.

Digression: The astrophysical parameters of our planet are well studied and known. Earth is the largest and densest planet of all the other inner planets in the solar system. It is here that natural physical conditions have been preserved under which the existence of water is possible. Our planet has a stable magnetic field that holds the atmosphere. Earth is the most well studied planet. The subsequent study is mainly of not only theoretical interest, but also practical one.

Mars closes the parade of terrestrial planets. The subsequent study of this planet is mainly not only of theoretical interest, but also of practical interest, associated with human exploration of extraterrestrial worlds. Astrophysicists are attracted not only by the relative proximity of this planet to Earth (on average 225 million km), but also by the absence of difficult climatic conditions. The planet is surrounded by an atmosphere, although it is in an extremely rarefied state, has its own magnetic field, and temperature differences on the surface of Mars are not as critical as on Mercury and Venus.

Like Earth, Mars has two satellites - Phobos and Deimos, the natural nature of which has recently been questioned. Mars is the last fourth planet with a rocky surface in the solar system. Following the asteroid belt, which is a kind of inner boundary of the solar system, begins the kingdom of gas giants.

The largest cosmic celestial bodies of our solar system

The second group of planets that are part of the system of our star has bright and large representatives. These are the largest objects in our solar system, which are considered the outer planets. Jupiter, Saturn, Uranus and Neptune are the most distant from our star, huge by earthly standards and their astrophysical parameters. These celestial bodies are distinguished by their massiveness and composition, which is mainly gaseous in nature.

The main beauties of the solar system are Jupiter and Saturn. The total mass of this pair of giants would be quite enough to fit in it the mass of all known celestial bodies of the Solar System. So Jupiter is the most big planet The solar system weighs 1876.64328 1024 kg, and the mass of Saturn is 561.80376 1024 kg. These planets have the most natural satellites. Some of them, Titan, Ganymede, Callisto and Io, are the largest satellites of the Solar System and are comparable in size to the terrestrial planets.

The largest planet in the solar system, Jupiter, has a diameter of 140 thousand km. In many respects, Jupiter more closely resembles a failed star - a striking example of the existence of a small solar system. This is evidenced by the size of the planet and astrophysical parameters - Jupiter is only 10 times smaller than our star. The planet rotates around its own axis quite quickly - only 10 Earth hours. The number of satellites, of which 67 have been identified to date, is also striking. The behavior of Jupiter and its moons is very similar to the model of the solar system. Such a number of natural satellites for one planet raises a new question: how many planets were there in the Solar System at the early stage of its formation. It is assumed that Jupiter, having a powerful magnetic field, turned some planets into its natural satellites. Some of them - Titan, Ganymede, Callisto and Io - are the largest satellites of the solar system and are comparable in size to the terrestrial planets.

Slightly smaller in size than Jupiter is its smaller brother, the gas giant Saturn. This planet, like Jupiter, consists mainly of hydrogen and helium - gases that are the basis of our star. With its size, the diameter of the planet is 57 thousand km, Saturn also resembles a protostar that has stopped in its development. The number of satellites of Saturn is slightly inferior to the number of satellites of Jupiter - 62 versus 67. Saturn's satellite Titan, like Io, a satellite of Jupiter, has an atmosphere.

In other words, the largest planets Jupiter and Saturn with their systems of natural satellites strongly resemble small solar systems, with their clearly defined center and system of movement of celestial bodies.

Behind the two gas giants come the cold and dark worlds, the planets Uranus and Neptune. These celestial bodies are located at a distance of 2.8 billion km and 4.49 billion km. from the Sun, respectively. Due to their enormous distance from our planet, Uranus and Neptune were discovered relatively recently. Unlike the other two gas giants, Uranus and Neptune contain large quantities of frozen gases - hydrogen, ammonia and methane. These two planets are also called ice giants. Uranus is smaller in size than Jupiter and Saturn and ranks third in the solar system. The planet represents the pole of cold of our star system. The average temperature on the surface of Uranus is -224 degrees Celsius. Uranus differs from other celestial bodies revolving around the Sun by its strong tilt on its own axis. The planet seems to be rolling, revolving around our star.

Like Saturn, Uranus is surrounded by a hydrogen-helium atmosphere. Neptune, unlike Uranus, has a different composition. The presence of methane in the atmosphere indicates Blue colour spectrum of the planet.

Both planets move slowly and majestically around our star. Uranus orbits the Sun in 84 Earth years, and Neptune orbits our star twice as long - 164 Earth years.

Finally

Our Solar System is a huge mechanism in which each planet, all satellites of the Solar System, asteroids and other celestial bodies move along a clearly defined route. The laws of astrophysics apply here and have not changed for 4.5 billion years. Along the outer edges of our solar system, dwarf planets move in the Kuiper belt. Comets are frequent guests of our star system. These space objects visit the inner regions of the Solar System with a periodicity of 20-150 years, flying within sight of our planet.

If you have any questions, leave them in the comments below the article. We or our visitors will be happy to answer them

Looking at the starry night sky, I often think about how big and vast our universe is. After all, after so many centuries of searching, we were able to study only a tiny part of it. Even the Solar System, our home, still contains many secrets and mysteries.

The solar system and what it is

The solar system is a group of celestial bodies continuously revolving around the sun. Central figure our system - the Sun, this star provides us with light and warmth. Celestial bodies are planets (such as the Earth), satellites (the Moon, for example), asteroids and meteorites (which are so scary in American blockbusters), dwarf planets, comets and cosmic dust. They all revolve around the Sun in their orbits counterclockwise at varying distances from it. The closer to the center, the correspondingly higher the temperature on the planet.


The approximate age of our system is 4.5 million years. Researchers suggest that the system arose after a supernova explosion, from dust and gas particles remaining after the explosion and our planets were formed. The system includes eight planets.

Major participants in the solar system

For a long time it was believed that there were nine planets in the system. But after its discovery in 2005, Pluto was demoted and relegated to the category of dwarf planets. This is due to the fact that scientists have discovered several planets with characteristics similar to Pluto, and in order not to cause confusion, scientists have named the signs by which the planets will be identified. This includes the presence of gravity, rotation around the Sun and getting rid of space debris in its orbit. These parameters fit:


Thus, several dwarf planets appeared in the Solar System (Pluto, Orcus, Eris, Haumea, Makeake, Quaoar, Sedna) and, who knows, perhaps there are even more. After all, every day scientists make more and more new discoveries about our common home. And not only in relation to new planets. After all, what the solar system is is a mystery that we have yet to solve.

> Solar system

solar system– planets in order, the Sun, structure, system model, satellites, space missions, asteroids, comets, dwarf planets, interesting facts.

solar system- a place in outer space in which the Sun, the planets in order, and many other space objects and celestial bodies are located. The solar system is the most precious place in which we live, our home.

Our Universe is a huge place where we occupy a tiny corner. But for earthlings, the Solar System seems to be the most vast territory, the farthest corners of which we are only beginning to approach. And it still hides a lot of mysterious and mysterious formations. So, despite centuries of study, we have only opened the door to the unknown. So what is the solar system? Today we will look at this issue.

Discovering the Solar System

In fact, you need to look into the sky and you will see our system. But few peoples and cultures understood exactly where we exist and what place we occupy in space. For a long time we thought that our planet was static, located in the center, and other objects rotated around it.

But still, even in ancient times, supporters of heliocentrism appeared, whose ideas would inspire Nicolaus Copernicus to create a true model where the Sun was located in the center.

In the 17th century, Galileo, Kepler and Newton were able to prove that planet Earth revolves around the star Sun. The discovery of gravity helped to understand that other planets follow the same laws of physics.

The revolutionary moment came with the advent of the first telescope from Galileo Galilei. In 1610, he noticed Jupiter and its moons. This will be followed by the discovery of other planets.

In the 19th century, three important observations were made that helped to calculate the true nature of the system and its position in space. In 1839, Friedrich Bessel successfully identified an apparent shift in stellar position. This showed that there is a huge distance between the Sun and the stars.

In 1859, G. Kirchhoff and R. Bunsen used the telescope to conduct a spectral analysis of the Sun. It turned out that it consists of the same elements as the Earth. The parallax effect can be seen in the bottom picture.

As a result, Angelo Secchi was able to compare the spectral signature of the Sun with the spectra of other stars. It turned out that they practically converge. Percival Lowell carefully studied the distant corners and orbital paths of the planets. He guessed that there was still an undisclosed object - Planet X. In 1930, Clyde Tombaugh noticed Pluto at his observatory.

In 1992, scientists expanded the boundaries of the system by discovering a trans-Neptunian object, 1992 QB1. From this moment on, interest in the Kuiper belt begins. This is followed by the findings of Eris and other objects from Michael Brown's team. All this will lead to a meeting of the IAU and the displacement of Pluto from the status of a planet. Below you can study in detail the composition of the Solar system, considering all the solar planets in order, the main star the Sun, the asteroid belt between Mars and Jupiter, the Kuiper belt and the Oort Cloud. The solar system also contains the largest planet (Jupiter) and the smallest (Mercury).

Structure and composition of the solar system

Comets are clumps of snow and dirt filled with frozen gas, rocks and dust. The closer they get to the Sun, the more they heat up and emit dust and gas, increasing their brightness.

Dwarf planets orbit the star, but have been unable to remove foreign objects from orbit. They are smaller in size than standard planets. The most famous representative is Pluto.

The Kuiper Belt lies beyond the orbit of Neptune, filled with icy bodies and formed as a disk. The most famous representatives are Pluto and Eris. Hundreds of ice dwarfs live on its territory. The farthest away is the Oort Cloud. Together they act as a source of arriving comets.

The solar system is only a small part of the Milky Way. Beyond its border there is a large-scale space filled with stars. At the speed of light it would take 100,000 years to cover the entire area. Our galaxy is one of many in the Universe.

In the center of the system is the main and only star - the Sun (main sequence G2). The first are the 4 terrestrial planets (inner), the asteroid belt, 4 gas giants, the Kuiper belt (30-50 AU) and the spherical Oort Cloud, extending to 100,000 AU. to the interstellar medium.

The Sun contains 99.86% of the entire system mass, and gravity is superior to all forces. Most of the planets are located near the ecliptic and rotate in the same direction (counterclockwise).

Approximately 99% of the planetary mass is represented by gas giants, with Jupiter and Saturn covering more than 90%.

Unofficially, the system is divided into several sections. The inner one includes 4 terrestrial planets and an asteroid belt. Next comes the outer system with 4 giants. A zone with trans-Neptunian objects (TNOs) is separately identified. That is, you can easily find the outer line, since it is marked by the large planets of the solar system.

Many planets are considered mini-systems because they have a group of satellites. Gas giants also have rings - small bands of small particles revolving around the planet. Typically large moons arrive in a gravitational block. On the lower layout you can see a comparison of the sizes of the Sun and the planets of the system.

The sun is 98% hydrogen and helium. Terrestrial planets are endowed with silicate rock, nickel and iron. The giants consist of gases and ices (water, ammonia, hydrogen sulfide and carbon dioxide).

Bodies in the Solar System that are distant from the star have low temperatures. From here, the ice giants (Neptune and Uranus) are distinguished, as well as small objects beyond their orbits. Their gases and ices are volatile substances that can condense at a distance of 5 AU. from the sun.

Origin and evolutionary process of the Solar System

Our system appeared 4.568 billion years ago as a result of the gravitational collapse of a large molecular cloud represented by hydrogen, helium and a small amount of heavier elements. This mass collapsed, causing rapid rotation.

Most of the mass gathered in the center. The temperature was rising. The nebula was shrinking, increasing the acceleration. This resulted in flattening into a protoplanetary disk containing a hot protostar.

Due to the high boiling level near the star, only metals and silicates can exist in solid form. As a result, 4 terrestrial planets appeared: Mercury, Venus, Earth and Mars. Metals were scarce, so they were unable to increase their size.

But the giants appeared further out, where the material was cool and allowed the volatile ice compounds to remain solid. There was much more ice, so the planets dramatically increased in size, attracting huge amounts of hydrogen and helium into the atmosphere. The remnants failed to become planets and settled in the Kuiper belt or retreated to the Oort Cloud.

Over 50 million years of development, the pressure and density of hydrogen in the protostar triggered nuclear fusion. Thus the Sun was born. The wind created the heliosphere and scattered gas and dust into space.

The system remains in its usual state for now. But the Sun develops and after 5 billion years completely transforms hydrogen into helium. The core will collapse, releasing a huge energy reserve. The star will increase in size by 260 times and become a red giant.

This will lead to the death of Mercury and Venus. Our planet will lose life because it will become hot. Eventually, the outer layers of stars will burst into space, leaving behind a white dwarf the size of our planet. A planetary nebula will form.

Inner Solar System

This is a line with the first 4 planets from the star. They all have similar parameters. This is a rocky type, represented by silicates and metals. Closer than the giants. They are inferior in density and size, and also lack huge lunar families and rings.

Silicates form the crust and mantle, and metals are part of the cores. All except Mercury have an atmospheric layer that allows them to shape weather conditions. Impact craters and tectonic activity are visible on the surface.

Closest to the star is Mercury. It is also the tiniest planet. The magnetic field reaches only 1% of Earth's, and the thin atmosphere causes the planet to be half-hot (430°C) and freezing (-187°C).

Venus similar in size to the Earth and has a dense atmospheric layer. But the atmosphere is extremely toxic and acts as a greenhouse. It consists of 96% carbon dioxide, along with nitrogen and other impurities. Dense clouds are made from sulfuric acid. There are many canyons on the surface, the deepest of which reaches 6,400 km.

Earth best studied because this is our home. It has a rocky surface covered with mountains and depressions. In the center is a heavy metal core. There is water vapor in the atmosphere, which smoothes the temperature regime. The Moon rotates nearby.

Because of appearance Mars received the nickname Red Planet. The color is created by the oxidation of iron materials on the top layer. It is endowed with the largest mountain in the system (Olympus), rising to 21229 m, as well as the deepest canyon - Valles Marineris (4000 km). Much of the surface is ancient. There are ice caps at the poles. A thin atmospheric layer hints at water deposits. The core is solid, and next to the planet there are two satellites: Phobos and Deimos.

Outer Solar System

Gas giants are located here - large planets with lunar families and rings. Despite their size, only Jupiter and Saturn can be seen without the use of telescopes.

The largest planet in the solar system is Jupiter with a rapid rotational speed (10 hours) and an orbital path of 12 years. The dense atmospheric layer is filled with hydrogen and helium. The core can reach the size of the Earth. There are many moons, faint rings and the Great Red Spot - a powerful storm that has not calmed down since the 4th century.

Saturn- a planet that is recognized by its gorgeous ring system (7 pieces). The system contains satellites, and the hydrogen and helium atmosphere rotates rapidly (10.7 hours). It takes 29 years to go around the star.

In 1781, William Herschel found Uranus. A day on the giant lasts 17 hours, and the orbital path takes 84 years. Holds huge amounts of water, methane, ammonia, helium and hydrogen. All this is concentrated around the stone core. There is a lunar family and rings. Voyager 2 flew to it in 1986.

Neptune– a distant planet with water, methane, ammonium, hydrogen and helium. There are 6 rings and dozens of satellites. Voyager 2 also flew by in 1989.

Trans-Neptunian region of the Solar System

Thousands of objects have already been found in the Kuiper belt, but it is believed that up to 100,000 with a diameter of more than 100 km live there. They are extremely small and located at large distances, so the composition is difficult to calculate.

The spectrographs show an icy mixture of hydrocarbons, water ice and ammonia. Initial analysis showed a wide color range: from neutral to bright red. This hints at the richness of the composition. A comparison of Pluto and KBO 1993 SC showed that they are extremely different in surface elements.

Water ice was found in 1996 TO66, 38628 Huya and 20000 Varuna, and crystalline ice was noticed in Quavar.

Oort cloud and beyond the solar system

This cloud is believed to extend to 2000-5000 AU. and up to 50,000 a.u. from the star. The outer edge can extend to 100,000-200,000 au. The cloud is divided into two parts: spherical outer (20000-50000 AU) and internal (2000-20000 AU).

The outer one is home to trillions of bodies with a diameter of a kilometer or more, as well as billions with a width of 20 km. There is no exact information about the mass, but it is believed that Halley's comet is a typical representative. The total mass of the cloud is 3 x 10 25 km (5 lands).

If we focus on comets, most of the cloud bodies are composed of ethane, water, carbon monoxide, methane, ammonia and hydrogen cyanide. The population is 1-2% made up of asteroids.

Bodies from the Kuiper Belt and Oort Cloud are called trans-Neptunian objects (TNOs) because they are located further than Neptune's orbital path.

Exploring the Solar System

The size of the solar system still seems immense, but our knowledge has expanded significantly with the sending of probes into outer space. The boom in space exploration began in the mid-20th century. Now it can be noted that all solar planets have been approached at least once by terrestrial spacecraft. We have photos, videos, as well as soil and atmosphere analysis (for some).

The first artificial spacecraft was the Soviet Sputnik 1. He was sent into space in 1957. Spent several months in orbit collecting data on the atmosphere and ionosphere. In 1959, the United States joined with Explorer 6, which took pictures of our planet for the first time.

These devices provided a huge amount of information about planetary features. Luna-1 was the first to go to another object. It flew past our satellite in 1959. Mariner was a successful mission to Venus in 1964, Mariner 4 arrived at Mars in 1965, and the 10th mission passed Mercury in 1974.

Since the 1970s The attack on the outer planets begins. In 1973, Pioneer 10 flew past Jupiter, and the next mission visited Saturn in 1979. A real breakthrough was the Voyagers, which flew around large giants and their satellites in the 1980s.

The Kuiper Belt is being explored by New Horizons. In 2015, the device successfully reached Pluto, sending the first close images and a lot of information. Now he is rushing to distant TNOs.

But we longed to land on another planet, so rovers and probes began to be sent in the 1960s. Luna 10 was the first to enter lunar orbit in 1966. In 1971, Mariner 9 settled near Mars, and Verena 9 orbited the second planet in 1975.

Galileo first orbited near Jupiter in 1995, and the famous Cassini appeared near Saturn in 2004. MESSENGER and Dawn visited Mercury and Vesta in 2011. And the latter still managed to fly around the dwarf planet Ceres in 2015.

The first spacecraft to land on the surface was Luna 2 in 1959. This was followed by landings on Venus (1966), Mars (1971), asteroid 433 Eros (2001), Titan and Tempel in 2005.

Currently, manned vehicles have only visited Mars and the Moon. But the first robotic one was Lunokhod-1 in 1970. Spirit (2004), Opportunity (2004) and Curiosity (2012) landed on Mars.

The 20th century was marked by the space race between America and the USSR. For the Soviets it was the Vostok program. The first mission came in 1961, when Yuri Gagarin found himself in orbit. In 1963, the first woman flew, Valentina Tereshkova.

In the USA they developed the Mercury project, where they also planned to launch people into space. The first American to go into orbit was Alan Shepard in 1961. After both programs ended, countries focused on long-term and short-term flights.

The main goal was to land a man on the moon. The USSR was developing a capsule for 2-3 people, and Gemini was trying to create a device for a safe lunar landing. It ended with Apollo 11 successfully landing Neil Armstrong and Buzz Aldrin on the moon in 1969. In 1972, 5 more landings were carried out, and all were Americans.

The next challenge was the creation of a space station and reusable vehicles. The Soviets formed the Salyut and Almaz stations. The first station with a large number crews became NASA's Skylab. The first settlement was the Soviet Mir, operating in 1989-1999. In 2001 it was replaced by the International Space Station.

The only reusable spacecraft was Columbia, which completed several orbital flights. The 5 shuttles completed 121 missions before retiring in 2011. Due to accidents, two shuttles crashed: Challenger (1986) and Columbia (2003).

In 2004, George W. Bush announced his intention to return to the Moon and conquer the Red Planet. This idea was also supported by Barack Obama. As a result, all efforts are now spent on exploring Mars and plans to create a human colony.

All these flights and sacrifices have led to a better understanding of our system, its past and future. The modern model contains 8 planets, 4 dwarfs and a huge number of TNOs. Let's not forget about the army of asteroids and planetesimals.

On the page you can find out not only useful information about the Solar system, its structure and size, but also get detailed description and characteristics of all planets in order with names, photos, videos, diagrams and distance from the Sun. The composition and structure of the solar system will no longer be a mystery. Also use our 3D model to explore all the celestial bodies yourself.

The Earth has its own brothers and sisters in the solar system. It is very likely that other stars like the Sun have their own planetary systems. Studying the question of what the planets of the solar system are made of, as well as some of our neighbors, will allow us to better understand the planet on which we live.

The shape of these planets is similar.

Composition of objects in our planetary system

Planets closer to the Sun are called inner, or terrestrial, planets because they are similar in size, specific density and composition to Earth. These include Mercury, Venus, Earth and Mars.
Planetary system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and our mother Earth.

More distant planets are called outer or Jupiterian planets. They differ from the terrestrial planets, but they also have many related features.

If the closer and smaller planets consist of stone, then the more distant ones are made of gaseous substances.

If specifically what the planets of the solar system are made of:


We know nearby planets much better, although studying them is very difficult.

Even famous astronomers complained that they could not get a good look at Mercury, since this planet is visible for a very short time before sunrise and low on the horizon, which makes observations extremely difficult.

Our knowledge of the planets of the solar system is now incomparably wider than it was several decades ago. The study of planets is one of the most interesting areas of modern scientific research. And yet, or maybe that’s why there are still many blank spots here and, thanks to intensive work, their number is constantly increasing.

Every day, automatic stations created with the latest technology send a lot of new data that confirm, but often change our ideas about our closest neighbors, and raise new questions that scientists must answer.

Field studies

Current knowledge regarding the surface composition and internal structure of planets is based on measurements from automatic stations. This uses the experience gained from studying the structure and composition of the Earth.

But what are all the measurements taken or taken at a distance compared to an actual piece of rock brought back from the Moon, which can be weighed, measured, sat over, and ad infinitum invented new processes and methods for obtaining as much information as possible from it?

But we have more than just a piece of the Moon on Earth. We have another group of witnesses who can tell much more than the surface of the already finished Moon, who know this, but are still silent. These are meteorites, which are like a book written by someone about the development of our system, individual pages of which are dropped onto the surface of the Earth without observing their sequence. Although we know.

When we manage to find out exactly what the planets are made of, we will be able to correctly fold the pages and read this planetary book...