The solar system is part of the Milky Way, and it, in turn, is a spiral galaxy, around the center of which the Sun revolves - the largest and heaviest object in the solar system, which is its heart. The sun, in its system, has eight planets with their satellites, many asteroids, comets and an incredible number of meteoroids. The planets of the solar system are divided into two types: the first is the terrestrial group, and the second is the giant planets.

The structure of the solar system has a significant impact not only on the planets, but also on their satellites, asteroids, comets and countless meteor elements that are also part of it.

This includes Mercury, Venus, Earth and Mars. Their characteristic features are small size and weight. As a rule, their composition includes metals and rocks, due to which they are distinguished by a significant density. The terrestrial planets are located closer to the Sun than other cosmic bodies.

giant planets

Jupiter, Saturn, Uranus and Neptune. They are characterized by a large size and low density, due to their predominantly gas composition. Despite this, the giant planets have strong gravity and have a considerable number of satellites, only Jupiter has 63 of them. These huge cosmic bodies are located at a distance from the Sun.

asteroid rings

The first ring of asteroids is located on the border of two groups of celestial bodies - in the region of Mars and Jupiter and is considered the main, and the second - the final element of the solar system, it is located behind Pluto, in the recent past the ninth major planet, it is called the Kuiper belt. These asteroids are also called minor planets, in our time about 10,000 asteroids in the main ring have been studied, presumably their number is 300,000.

dwarf planets

This is Pluto, which received this status in 2006, the brightest representative of the main asteroid ring - Ceres and the distant one - Eris. Dwarf planets are those that have a diameter of about 1000 km.

Comets

Objects of the solar system, consisting of ice and dust. They exist outside the second asteroid ring, practically in interstellar space, and only a few of them fall into the gravitational pull of the Sun, collapsing, forming a trail of steam and dust.

The pattern of the solar system

The main regularity is the movement of the planets. They move in the same direction relative to the Sun, namely against the movement of the clock hands. Venus and Uranus, which moves almost on its side, as well as some satellites of the planets, have a different direction of rotation. Space bodies rotate in an orbit, the shape of which is close to a circle, however, the orbits of Mercury and Pluto have an elongated trajectory, and comets also move along such orbits.

Journey through the solar system

solar system is one of 200 billion star systems located in the Milky Way galaxy. It is located approximately in the middle between the center of the galaxy and its edge.
The solar system is a certain accumulation of celestial bodies that are connected by gravitational forces with a star (the Sun). It includes: the central body - the Sun, 8 large planets with their satellites, several thousand small planets or asteroids, several hundred observed comets and an infinite number of meteoric bodies.

Large planets are divided into 2 main groups:
- terrestrial planets (Mercury, Venus, Earth and Mars);
- planets of the Jupiter group or giant planets (Jupiter, Saturn, Uranus and Neptune).
Pluto has no place in this classification. In 2006, it was found that Pluto, due to its small size and great distance from the Sun, has a low gravitational field and its orbit is not similar to the orbits of planets adjacent to it, closer to the Sun. In addition, the elongated ellipsoidal orbit of Pluto (for the rest of the planets it is almost circular) intersects with the orbit of the eighth planet of the solar system - Neptune. That is why, since recent times, it was decided to deprive Pluto of the status of a "planet".

terrestrial planets are relatively small and have a high density. Their main constituents are silicates (silicon compounds) and iron. At giant planets virtually no hard surface. These are huge gas planets, formed mainly from hydrogen and helium, the atmosphere of which, gradually condensing, smoothly passes into a liquid mantle.
Of course, the main elements The solar system is the sun. Without it, all the planets, including ours, would have scattered over great distances, and perhaps even beyond the galaxy. It is the Sun, due to its huge mass (99.87% of the mass of the entire solar system), that creates an incredibly powerful gravitational effect on all planets, their satellites, comets and asteroids, forcing each of them to rotate in its own orbit.

AT solar system, in addition to planets, there are two areas filled with small bodies (dwarf planets, asteroids, comets, meteorites). The first area is Asteroid Belt, which is between Mars and Jupiter. In composition, it is similar to the terrestrial planets, as it consists of silicates and metals. Beyond Neptune is a second region called Kuiper belt. It has many objects (mostly dwarf planets) consisting of frozen water, ammonia and methane, the largest of which is Pluto.

The Koipner belt begins just after the orbit of Neptune.

Its outer ring ends at a distance

8.25 billion km from the Sun. This is a huge ring around the whole

The solar system is an infinite

the amount of volatile substances from ice floes of methane, ammonia and water.

The Asteroid Belt is located between the orbits of Mars and Jupiter.

The outer boundary is located 345 million km from the Sun.

Contains tens of thousands, possibly millions of objects more than one

kilometers in diameter. The largest of them are dwarf planets

(diameter from 300 to 900 km).

All planets and most other objects revolve around the Sun in the same direction as the Sun's rotation (counterclockwise as viewed from the north pole of the Sun). Mercury has the highest angular velocity - it manages to make a complete revolution around the Sun in just 88 Earth days. And for the most distant planet - Neptune - the period of revolution 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, and Uranus rotates almost "lying on its side" (axis tilt is about 90 °).

It was previously assumed that boundary of the solar system ends just after Pluto's orbit. However, in 1992, new celestial bodies were discovered, which undoubtedly belong to our system, since they are directly under the gravitational influence of the Sun.

Each celestial object is characterized by such concepts as a year and a day. Year- this is the time for which the body turns around the Sun at an angle of 360 degrees, i.e. makes a complete circle. BUT day is the period of rotation of the body around its own axis. The closest planet from the Sun, Mercury, revolves around the Sun in 88 Earth days, and around its axis - in 59 days. This means that even less than two days pass on the planet in one year (for example, on Earth, one year includes 365 days, i.e. that is how many times the Earth turns around its axis in one revolution around the Sun). While on the most distant, from the Sun, dwarf planet Pluto, a day is 153.12 hours (6.38 Earth days). And the period of revolution around the Sun is 247.7 Earth years. That is, only our great-great-great-great-grandchildren will catch the moment when Pluto finally goes all the way in its orbit.

galactic year. In addition to circular motion in orbit, the solar system performs vertical oscillations relative to the galactic plane, crossing it every 30-35 million years and ending up either in the northern or southern galactic hemisphere.
Disturbing factor for the planets solar system is their gravitational influence on each other. It slightly changes the orbit compared to that in which each planet would move under the action of the Sun alone. The question is whether these perturbations can accumulate up to the fall of the planet on the Sun or its removal beyond solar system, or they are periodic and the orbital parameters will only fluctuate around some average values. The results of theoretical and research work carried out by astronomers over the past 200 years speak in favor of the second assumption. This is also evidenced by the data of geology, paleontology and other Earth sciences: for 4.5 billion years, the distance of our planet from the Sun has practically not changed. And in the future, neither falling on the Sun, nor leaving solar system, as well as the Earth, and other planets are not threatened.

Planets of the solar system

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

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

As defined by MAC, 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 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, for ease of understanding, equated to the earth's year, is 88 days, while Mercury has time to complete a revolution around its own axis only one and a half times. Thus, its day lasts approximately 59 Earth days. For a long time it was believed that this planet was always turned to the Sun by the same side, since the periods of its visibility from the Earth were repeated with a frequency approximately equal to four Mercury days. This misconception was dispelled with the advent of the possibility of using radar research and conducting 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, as seen by the MESSENGER spacecraft

Mercury's proximity to the Sun has caused it to experience the largest temperature fluctuations of any of 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 have been identified in the atmosphere. There is a theory that it was previously a satellite of Venus, but so far this remains unproven. It has no satellites of its own.

Venus

The second planet from the Sun, the atmosphere of which 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 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 amounts.

Venus in the UV spectrum

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

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 develop. At least life as we know it. The radius of the Earth is 6371 km and, unlike the rest of the celestial bodies in our system, more than 70% of its surface is covered with water. The rest of the space is occupied by the 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 a change in the landscape. The speed of the planet moving along it is 29-30 km / s.

Our planet from space

One rotation around its axis takes almost 24 hours, and a complete orbit lasts 365 days, which is much longer in comparison with the nearest neighboring planets. The Earth day and year are also taken as a standard, but this is done only for the convenience of perceiving time intervals on other planets. The Earth has one natural satellite, the Moon.

Mars

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

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

The radius is almost half that of the 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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• The 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 moon. Like the Moon, Mercury is practically devoid of an atmosphere and cannot smooth out the traces of impact from the fall of meteorites, therefore, like the Moon, it is covered with craters. The day side of Mercury is very hot on the Sun, and on the night side the temperature drops hundreds of degrees below zero. In the craters of Mercury, which are located at the poles, there is ice. Mercury makes one revolution around the Sun in 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 in a thick and toxic atmosphere that creates a strong greenhouse effect. This scorched world is hot enough to melt lead. Radar images through the mighty 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 such a way that life became possible.

• Mars

  Although details of the surface of Mars are difficult to see from Earth, telescope observations show that Mars has seasons and white spots at the poles. For decades, people have assumed that the bright and dark areas on Mars are patches of vegetation and that Mars might be a suitable place for life, and that water exists in the polar caps. When the Mariner 4 spacecraft flew by Mars in 1965, many of the scientists were shocked to see pictures of the bleak, cratered planet. Mars turned out to be a dead planet. More recent missions, however, have revealed that Mars holds many mysteries that have yet to be solved.

• Jupiter

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

• Saturn

  Saturn is the most distant of the five planets that were known before the invention of the telescope. Like Jupiter, Saturn is made up mostly of hydrogen and helium. Its volume is 755 times 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 with 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

  Nearly 4.5 billion kilometers from the Sun, distant Neptune rotates. It takes 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 Neptune's orbit for about 20 out of 248 years during which it makes one revolution around the Sun.

• Pluto

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

The planets are giants

There are four gas giants located beyond the orbit of Mars: Jupiter, Saturn, Uranus, Neptune. They are in the outer solar system. They differ in 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. A year on Jupiter is not the longest in the solar system, lasting 4333 Earth days (incomplete 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 orbit of the planet, a fairly accurate and clear model of the solar system is needed. The largest of them are Callisto, Ganymede, Io and Europa. At the same time, Ganymede is the largest satellite of the planets in the entire solar system, its radius is 2634 km, which is 8% larger 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 largest in the solar system. In comparison with other planets, the composition of chemical elements is most similar to the Sun. The surface radius 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 far 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 than it, but no less famous for this - 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 rest.

For a long time, the rings on Saturn were considered a unique phenomenon, inherent only to him. Only recently it was found that all gas giants have rings, but the rest 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.

Our planetary system consists of more than just the Sun and its surrounding planets. There are still a huge number of objects revolving in their orbits, but having a much smaller size to give them a full planetary status. For such objects in 2006, the International Astronomical Union introduced the term "small body of the solar system." These include interplanetary matter (gas and dust), asteroids, meteorites, comets and dwarf planets.

asteroid belt

The name of this mysterious place in the solar system - the main asteroid belt - was introduced in the middle of the 19th century by the German scientist and educator Alexander von Humboldt. The total mass of the cluster of flying rocks with a diameter from a meter to hundreds of kilometers is approximately 4% of the lunar mass, with more than half of it contained in the four largest bodies: Ceres, Pallas, Vesta and Hygiea. Their average diameter is close to 400 km, and the largest of them - Ceres - can even be considered a real dwarf planet (its diameter is more than 950 km, and its mass exceeds the total mass of Pallas and Vesta). However, the vast majority of the many millions of main belt asteroids are much smaller in size, they are only tens of meters in diameter.

Asteroids are considered bodies with a diameter of more than 30 m, smaller ones are called meteoroids, or meteorites. There are quite a few especially large bodies in the main asteroid belt, for example, there are only about 200 hundred-kilometer asteroids, and about a thousand asteroids with a radius of more than 15 km are known. The main population of the main belt, apparently, forms several million asteroids with a diameter of tens and hundreds of meters.

Planetary astronomers are still arguing about the reasons for the appearance of the main asteroid belt, but most agree that the monstrous gravity of Jupiter played a decisive role, either preventing the formation of a full-fledged planet, or, on the contrary, tearing it apart, the multiple collisions of which and led to today's picture of this orbital swarm of asteroids.

As a result, many asteroids broke up into smaller fragments. Most of them were ejected by gravity to the outskirts of the solar system or switched to very elongated orbits, moving along which (and returning to the inner part of the solar system) they collided with terrestrial planets during the era of late heavy bombardment, about 3.5 billion years ago . This explains the low density of the current state of the asteroid belt. Collisions between asteroids occur constantly, even taking into account the sparseness of the modern asteroid belt, which forms many asteroid families with similar orbits and chemical structures.

Asteroid groups

Among the asteroids, near-Earth cupids and Apollos are distinguished (named after their most famous representatives - the asteroids Amur and Apollo). The orbits of the cupids are completely outside the earth's orbit, the trajectory of the Apollos crosses the earth's from the outside.

Study of small bodies

The largest representatives of the main asteroid belt - Ceres, Pallas, Juno and Vesta - were discovered at the beginning of the 19th century, and Astrea and Hebe - in the middle. Unlike other planets, even in the most powerful telescopes of the time, they all looked like points of light, indistinguishable from ordinary stars in the absence of movement. Therefore, new celestial bodies began to be considered a separate class of star-like objects.

A new phase in the study of asteroids began with the use of astrophotography in 1891, which consisted of shooting with a long exposure, so that moving, poorly visible bodies leave clear lines of light. With the help of astrophotography, over a thousand asteroids were discovered over the next three decades, and today their number is about 300 thousand and continues to grow, and modern systems for searching for new asteroids make it possible to detect them automatically, with little or no human intervention. The closest attention is paid, first of all, to large objects capable of invading the earth's atmosphere, along with some comets and meteoroids.

The structure and composition of asteroids

The evolution of the largest belt asteroids involved a process of gravitational separation as they experienced heating that melted their silicate material, releasing metal cores and lighter silicate shells. So, large asteroids even had a kind of basaltic crust, just like the inner planets of the terrestrial group.

The theory of the emergence of the main asteroid belt assumes that at first the population of the belt should have included many large objects in which differentiation of the internal structure occurred. Such asteroids could have all the signs of minor planets along with a crust and mantle of basaltic rocks. Accordingly, in the future, more than half of the fragments of large bodies would have to consist of basalt. Nevertheless, basalt bodies are almost never found in the main belt. At one time, it was even believed that almost all basaltic asteroids were fragments of Vesta's crust, but more detailed studies showed a difference in their chemical composition, which indicates their separate
origin.

It is interesting that when the main belt was in the process of formation, the so-called snow line appeared in it, within which the surface of asteroids did not heat up above the temperature of ice melting. Therefore, water ice could form on asteroids formed outside this line, which led to the appearance of space icebergs with a large amount of ice.

Similar considerations were confirmed by the discovery of new varieties of inhabitants of the main asteroid belt in the form of relatively small comets inhabiting the outer part of the belt far beyond the snow line. Perhaps it was these "snow asteroids" that became the sources of water (and, consequently, life) in the earth's oceans, hitting our planet during a comet bombardment. This hypothesis is indirectly confirmed by the difference in the isotopic composition of comets arriving from the distant outskirts of the solar system, with the distribution of isotopes in the water of the Earth's hydrosphere. At the same time, the isotopic composition of small comets located in the outer part of the main asteroid belt is quite similar to that of the Earth, therefore, it can be assumed that these asteroids were sources of terrestrial water.

Between the composition of the asteroid and its distance from the Sun, one can trace a well-defined relationship. For example, stony silicate asteroids are located much closer to the sun than carbonaceous clay asteroids, which contain traces of water in a bound state and even ordinary water ice. Asteroids close to the Sun also have a higher reflectivity than central and peripheral ones. Astronomers attribute this to the effect of solar radiation, which “blows out” lighter elements, such as water and gases, to the periphery. Thus, water ice condensed on asteroids in the outer region of the main belt.

Classification of asteroids

Of the main characteristics of asteroids, it is worth mentioning their color indicators, surface reflectivity, and characteristics of the spectrum of reflected sunlight. Initially, this classification defined only three main classes of asteroids:

• class C - carbon, 75% of known asteroids;
• class S - silicate, 17% of known asteroids;
• class M - metal, most of the rest.

This list was later expanded, and the number of classes continues to grow as asteroids are explored.

The relatively high concentration of large and medium-sized bodies in the central region of the main belt suggests the possibility of quite frequent, by astronomical standards, crushing collisions that occur at least once every tens of million years. At the same time, they are crushed into separate fragments of various sizes. However, if asteroids meet at relatively low speeds, the reverse process of their “sticking together” is possible, when they combine into one larger body. In the modern astronomical era, crushing and dispersion of parts of asteroids undoubtedly dominate, but 4 billion years ago, it was the processes of enlargement that led to the formation of the planets of the solar system.

Since then, the fragmentation of asteroid fragments into meteoroids has completely changed the appearance of the main asteroid belt, filling it with vast trails of tiny grains and dust from microparticles with a radius of several hundred micrometers. The consequences of such crushing, “grinding” and mixing with additives, in addition to asteroid dust, also emitted by comets, cause the phenomenon of zodiacal light (a weak post-sunset and pre-dawn glow observed in the ecliptic plane, having the form of a blurry triangle).

carbon asteroids. Such bodies make up more than three-quarters of the population of the main belt and contain a large percentage of elemental carbon compounds. Their number is especially large in the outer regions of the main belt. Externally, carbonaceous asteroids have a dull dark red hue and are quite difficult to detect. Apparently, the main belt of asteroids contains quite a lot of such bodies, which can be found by radiation in the invisible infrared range due to the presence of water in them. The largest representative of carbonaceous asteroids is Hygiea.

silicate asteroids. A fairly common class of asteroids are class S silicate bodies, grouped in the inner part of the belt. Their surface is covered with various silicates and some metals, mainly iron and magnesium, in the complete absence of carbon compounds. All this is the result of significant changes caused by the melting and separation of substances.

metal asteroids. This is also the name of meteoroids of class M of the main belt. They are rich in nickel and iron. They are about 10% of all bodies. Moderately reflective, these objects could be parts of the metallic cores of asteroids like Ceres, formed during the formation of the solar system and destroyed in mutual collisions.

Since the kinetic energy of the collision of asteroids can reach very significant values, their fragments can spread throughout the solar system, falling into the atmosphere of our planet. Today, there are tens of thousands of all kinds of meteorites, of which almost all (99.8%) came from the main asteroid belt.

New source of resources

In the tasks of colonizing the solar system, asteroids play an important role as a source of raw materials for construction and industrial production. It is even supposed to organize the transportation of the most valuable asteroids to the earth's orbit, where by that time space metallurgical enterprises will be operating. Main belt asteroids can be valuable sources of water ice, from which it is possible to obtain oxygen for breathing and hydrogen for fuel. And of course, space geologists of the future hope to find various rare minerals and metals, including nickel, iron, cobalt, titanium, platinum, molybdenum, rhodium, etc., under a thin crust of sintered basalts.

Asteroids are practically inexhaustible sources of resources, just one kilometer-diameter M-class iron-nickel body can contain a couple of billion tons of ore, several times the annual production of a mineral on Earth. Even more promising is the location of metallurgical production in space with vacuum melting and remelting of various space infrastructure products necessary for further research and development of near and, in the future, deep space.

The science

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

After Pluto ceased to be considered a planet of the solar system in 2006, and moved into the category of dwarf planets, the number of major planets has been reduced to 8.

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

Here are 10 facts you may not have known about the solar system.

1. The hottest planet is not closest to the Sun

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

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

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

2. The boundary of the solar system is a thousand times farther from Pluto

We tend to think that the solar system extends to the orbit of Pluto. Today, Pluto is not even considered a major planet, but this idea has remained in the minds of many people.

Scientists have discovered many objects orbiting the Sun, which are much further than Pluto. These are the so-called trans-Neptunian or Kuiper belt objects. The Kuiper belt extends for 50-60 astronomical units (the 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 made up of iron, oxygen, silicon, magnesium, sulfur, nickel, calcium, sodium and aluminum.

Although all of these elements have been found in various places throughout the universe, they are only trace elements that overshadow the abundance of hydrogen and helium. Thus, the Earth for the most part consists of rare elements. This does not speak of any special place on planet Earth, since the cloud from which the Earth formed contained a large amount of hydrogen and helium. But since they are light gases, they were blown into space by the heat of the sun 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 once believed that there is a planet Vulcan, which is closer to the Sun than Mercury. Its possible existence was discussed 150 years ago to explain some of the features of Mercury's orbit. However, later observations ruled out the possibility of Vulcan's existence.

In addition, recent studies have shown that it is possible once there was a fifth giant planet, similar to Jupiter, which revolved around the Sun, but was ejected from the solar system due to gravitational interaction with other planets.

5. Jupiter has the largest ocean of all the planets

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

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

According to computer models on this planet, not only is the largest ocean in the solar system, its depth is approximately 40,000 km, that is, it 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 such large objects as planets could have natural satellites or moons. The fact that satellites exist is sometimes even used to determine what a planet really is. It seems counterintuitive that small cosmic bodies could have enough gravity to hold a satellite. After all, Mercury and Venus don't have them, and Mars only has two tiny moons.

But in 1993, the Galileo interplanetary station discovered the Dactyl satellite, just 1.6 km wide, near the asteroid Ida. Has since been found moons orbiting about 200 other minor planets, which greatly complicated the definition of "planet".

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 the Earth. Actually the outer atmosphere of the sun extends much further than the visible surface.

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

8. Saturn isn't the only planet with rings.

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

The ring system of Uranus is slightly more visible than that of Jupiter, and may have formed after the collision of small satellites. Neptune's rings are faint and dark, like those of Jupiter. The dim rings of Jupiter, Uranus and Neptune impossible to see through small telescopes from Earth, because Saturn became best known 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 atmospheres of Venus and Mars, which are much thicker and thinner, respectively, than those of Earth and are composed of carbon dioxide, Titan's atmosphere is mostly nitrogen.

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