Not so long ago, any educated person on the question of how many planets in the solar system would answer without thinking - nine. And would be right. If you do not particularly follow the events in the world of astronomy and are not a permanent viewer of Discovery Channel, today you answer the question as well. However, this time you will be wrong.

And the thing is what. In 2006, namely, on August 26, 2.5 thousand participants of the Congress of the International Astronomical Union took a sensational decision and actually crossed out Pluto from the list of planets Solar systemSince 76 years after the opening, he stopped satisfying the requirements of scientists to the planets.

Let's see for a start, what is the planet, as well as how many planets in the solar system left us astronomers, and consider each of them separately.

A bit of history

Earlier, the planet was considered to be any body that turns around the star, the light reflected from it and has a size greater than that of asteroids.

Also in Ancient Greece We mentioned seven glowing bodies that move across the sky against the background of fixed stars. These cosmic bodies were: the sun, Mercury, Venus, Moon, Mars, Jupiter and Saturn. Earth did not enter this list, since the ancient Greeks believed exactly the land center of all things. And only in the XVI century, Nikolai Copernicus, in his scientific work, under the name "about the appeal of the heavenly spheres" came to the conclusion that not the Earth, namely the Sun should be in the center of the Planet System. Therefore, the Sun and the Moon were removed from the list, and brought the land into it. And after the appearance of telescopes, Uranus and Neptune added, in 1781 and 1846, respectively.
Pluto was recently considered the last open planet of the solar system since 1930.

And here, after almost 400 years since the creation of Galileo Galileem first in the world of the telescope to observe the stars, the astronomer scientists came to the next definition of the planet.

Planet - This is a heavenly body that must satisfy four conditions:
The body should contact around the star (for example, around the Sun);
The body must have sufficient gravity to have a spherical or form close to it;
The body should not have the orbit of other large bodies near its orbit;

The body should not be a star.

In turn star - This is a cosmic body that emits light and is a powerful source of energy. This is explained in the first, which occurred in it by thermonuclear reactions, and secondly, the processes of gravitational compression, as a result of which a huge amount of energy is distinguished.

Planet solar system today

solar system - This is a planetary system that consists of a central star - the Sun - and all natural space objects appealing around it.

So, today the solar system consists of the eight planets: four inner, so-called planets of the earth group, and four external planets called gas giants.
The planets of the Earth Group include land, Mercury, Venus and Mars. All of them consist mainly of silicates and metals.

External planets are Jupiter, Saturn, Uranus and Neptune. The composition of gas giants includes mainly hydrogen and helium.

The dimensions of the planets of the solar system differ both inside the groups and between groups. Thus, the gas giants are much larger and massive than the planets of the earthly group.
The closer to the Sun is Mercury, then as removal: Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

It would be wrong to consider the characteristics of the planets of the solar system, without paying attention to its main component: the sun itself. Therefore, we will start with it.

The sun

The sun is a star that gave rise to everything alive in the solar system. Planets, dwarf planets and their satellites, asteroids, comets, meteorites and cosmic dust are treated around it.

The sun arose about 5 billion years ago, it is a spherical, hot plasma ball and has a mass that is more than 300 thousand times higher than the mass of the Earth. The temperature on the surface is more than 5000 degrees of Kelvin, and the kernel temperature is more than 13 million K.

The sun is one of the biggest and most bright stars In our galaxy, which is called the Galaxy Milky Way. The sun is located at a distance of about 26 thousand light years from the center of the Galaxy and makes a full turn around it around 230-250 million years old! For comparison, the Earth makes a full turn around the Sun for 1 year.

Mercury

Mercury is the smallest planet system that is closer to others to the sun. Mercury has no satellites.

The surface of the planet is covered with craters that have arisen about 3.5 billion years ago due to massive bombing by meteorites. The diameter of the crater can be from several meters to more than 1000 km.

The atmosphere of Mercury is strongly discharged, consists mainly of helium and is inflated by the solar wind. Since the planet is located very close to the Sun and has no atmosphere, which would maintain heat at night, the temperature on the surface ranges from -180 to +440 degrees Celsius.

For earthly standards, Mercury's full turn around the Sun commits 88 days. But Mercurian days are 176 Earth.

Venus

Venus - the second in the proximity to the sun planet of the solar system. With its sizes of Venus, only a little inferior to the earth, so it is sometimes called the "sister of the Earth". Satellites has no.

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

Carbon dioxide and, as a result, a greenhouse effect, a compacted atmosphere, as well as proximity to the Sun allow Venus to wear the title of "hot planet." The temperature on its surface can reach 460 ° C.

Venus is one of the brightest objects on the earthly heaven after the sun and the moon.

Land

Earth is the only planet known for today in the universe, which has a life. The land has the greatest dimensions, mass and density among the so-called internal planets of the solar system.

The age of the earth is about 4.5 billion years, and life appeared on the planet about 3.5 billion years ago. The moon is a natural satellite, the largest satellites of the planets of the earth group.

The atmosphere of the Earth is radically different from the atmospheres of the rest of the planets thanks to the presence of life. Most of the atmosphere consists of nitrogen, it also includes oxygen, argon, carbon dioxide and water vapor. The ozone layer and the magnetic field of the Earth, in turn weaken life-threatening effect of solar and cosmic radiation.

Due to carbon dioxide contained in the atmosphere, the greenhouse effect also takes place. It manifests itself not as much as on Venus, but without it the air temperature would be approximately 40 ° C below. Without the atmosphere and fluctuations in temperature, it would be very significant: according to scholars counting, from -100 ° C at night to + 160 ° F.

About 71% of the earth's surface occupies the world ocean, the remaining 29% is the continents and islands.

Mars

Mars is the seventh on the size of the planet in the solar system. "Red Planet", as it is also called due to availability large number Iron oxide in the ground. Mars has two satellites: Dimimos and Phobos.
The atmosphere of Mars is greatly discharged, and almost one and a half times longer than near the earth. Therefore, the average annual temperature on the planet is -60 ° C, and temperature drops in some places reach 40 degrees during the day.

Distinctive features of the surface of Mars are shock craters and volcanoes, valleys and deserts, icy polar caps like terrestrial. On Mars is the most high mountain In the Solar System: Extlined Volcano Olympus, whose height is 27 km! As well as the largest canyon: Marierin Valley, the depth of which reaches 11 km, and the length is 4500 km.

Jupiter

Jupiter is the largest planet of the solar system. It is 318 times heavier than the Earth, and almost 2.5 times more massive than all the planets of our system combined. In terms of its composition, Jupiter resembles the sun - it consists mainly of helium and hydrogen - and radiates a huge amount of heat equal to 4 * 1017 W. However, in order to become a star like the Sun, Jupiter must be even 70-80 times heavier.

Jupiter has a total of 63 satellites, listing only the biggest - Callisto, Ganymed, IO and Europe. Ganymed is the largest satellite in the solar system, it exceeds even Mercury in size.

Due to certain processes in the internal atmosphere of Jupiter, there are many vortex structures in its external atmosphere, for example, the bands of brown-red shades clouds, as well as a large red spot - a giant storm, known since the XVII century.

Saturn

Saturn is the second in the size of the planet of the solar system. Saturn business card is, of course, his rings system, which consists mainly of ice particles of different sizes (from the tenths of a millimeter to several meters), as well as mountain breeds And dust.

Saturn 62 satellites, the largest of which are Titan and Encelada.
In terms of its composition, Saturn resembles Jupiter, but it is also inferior in density even ordinary water.
The external atmosphere of the planet looks calm and homogeneous, which is explained by a very dense layer of fog. However, wind speed in places can reach 1800 km / h.

Uranus

Uranus is the first planet discovered using a telescope, as well as the only planet in the solar system, which turns around the sun, "lying on the side".
Uranus has 27 satellites that are named after Shakespeare's heroes. The greatest of them are Oberon, Titania and Umbol.

The composition of the planet differs from gas giants by the presence of a large number of high-temperature ice modifications. Therefore, along with Neptune, scientists have identified uranium to the category of "Ice Giants". And if Venus possesses the title of "the hottest planet" of the solar system, then uranium is the coldest planet with a minimum temperature of about -224 ° C.

Neptune

Neptune is the most remote from the center of the planet of the solar system. The history of its discovery is interesting: before watching the planet in the telescope, scientists with the help of mathematical calculations calculated its position in the sky. It happened after detecting inexplicable changes when uranium moved on its own orbit.

Today, 13 Neptune satellites are known for science. The largest of them is Triton - the only satellite that moves towards the opposite rotation of the planet. Anti-rotation of the planet also blows the fastest winds in the solar system: their speed reaches 2,200 km / h.

In composition, Neptune is very similar to Uranus, therefore is the second "ice giant". However, like Jupiter and Saturn, Neptun has an internal heat source and radiates 2.5 times more energy than it gets from the sun.
Blue colour The planet give traces of methane in the outer layers of the atmosphere.

Conclusion
Pluto, unfortunately, did not have time to get into our parade of the planets of the solar system. But it is absolutely not worth worrying about this, because all the planets remain in their places, despite changes in scientific views and concepts.

So, we answered the question how much planets in the solar system. They are only 8 .

Pluto The Mac decision (International Astronomical Union) no longer belongs to the planets of the solar system, and is a dwarf planet and even inferior in the diameter of the other dwarf Erida planet. Pluto designation 134340.

solar system

Scientists put forward many versions of our solar system. In the forties of the last century, Otto Schmidt put forward a hypothesis that the solar system arose because cold dust clouds pulled to the sun. Over time, the clouds have formed the foundations of future planets. IN modern science It is the theory of Schmidt is the main. Solar system represents only a small part of a large galaxy called the Milky Way. The Milky Way includes more than one hundred billion different stars. For awareness, such a simple truth was needed by millennium. The opening of the solar system did not occur immediately, step by step, on the basis of victories and errors, the knowledge system was formed. The main base for the study of the solar system was knowledge of Earth.

Basics and theory

The main milestones in the study of the solar system are a modern atomic system, a heliocentric system of Copernicus and Ptolemy. The most likely version of the origin of the system is considered the theory of a large explosion. In accordance with it, the formation of the galaxy began with the "running" of the elements of the megasystem. At the turn of the impenetrable house, our solar system was originated. It becomes just the sun - 99.8% of the total volume, the planets account for 0.13%, the remaining 0.0003% constitute various bodies of our system. Acquired division of planets into two conventional groups . The first include the planets of the Land: Actually, the Earth itself, Venus, Mercury itself. The main distinguishing characteristics of the planets of the first group is a relatively small area, hardness, a small amount of satellites. The second group includes uranium, Neptune and Saturn - they are distinguished by large dimensions (planets giants), they form helium and hydrogen gases.

In addition to the Sun and planets, our system also includes planetary satellites, comets, meteorites and asteroids.

Special attention should be paid to asteroid belts that are between Jupiter and Mars, and between Pluto and Neptune orbits. At the moment, there is no unambiguous version of such formations in science.
What a planet is not considered now the planet:

Pluto since its discovery until 2006 was considered a planet, but later, in the outer part of the solar system, many celestial bodies were opened, comparable in size with Pluto and even exceeding it. To avoid confusion, a new definition of the planet was given. Pluto did not come under this definition, so he was assigned a new "status" - dwarf planet. So, Pluto can serve as a response to the question: before he was considered a planet, and now - no. However, some scientists continue to assume that Pluto must be reclassified back into the planet.

Deposits of scientists

On the basis of research, scientists suggest that the sun approaches the middle of its life path. Unimaginably imagine what will happen if the sun goes out. But scientists say that this is not only possible, but also inevitably. The age of the Sun was determined with the help of the latest computer developments and found out that he had about five billion years. According to astronomical law, the life of a star, a similar sun, lasts about ten billion years. Thus, our solar system is located in the middle of the life cycle. What are scientists imply under the word "go out"? Huge solar energy is hydrogen energy, which becomes helium in the kernel. Every second, about six hundred tons of hydrogen in the Sun kernel is processed in helium. According to the estimates of scientists, the sun has already spent most of its hydrogen reserves.

If instead of the moon, the planets of the solar system would be:

The solar system includes: the sun is the central body; nine big planets with their satellites (more than 60); Small planets - asteroids (50-60 thousand); Comets and meteoric bodies (meteorites and meteors).

The sun - The closest star to us. The distance from the ground to the Sun is 149.6 million kilometers. This distance is conventionally called one astronomical unit - 1 AE. The light passes it in 8 minutes and 19 seconds.

The mass of the sun is 770 times the mass of all planets combined. In the volume of the Sun, 1 million such balls could fit as the Earth. In the sun focused 99.9% of the entire mass of the solar system.

The sun is a huge plasma ball (its radius is approximately 700,000 km), consisting of 80% of hydrogen and almost 20% of helium. In the depths of the Sun, thermonuclear reactions occur: hydrogen turns into helium, which is accompanied by a colossal release of energy.

The temperature on the surface of the Sun is approximately 6000 o C, and in its depths - 15-20 million degrees.

The intensity of the processes occurring on the surface of the Sun is periodically changing, while they say that solar activity changes. The period of change in the activity of the Sun is an average of 11 years. Simultaneously with the eleven-year-old cycle proceeds by century, more precisely, 80-90-year-old cycle solar activity. It is inconsistently overlapping at each other, they make noticeable changes in the processes committed in the geographical shell.

The following physical phenomena are delivered to the deepence on the degree of solar activity intensity: the magnetic storms, the frequency of polar beams, the amount of ultraviolet radiation, the intensity of thunderstorm activity, air temperature, atmospheric pressure, precipitation, etc. Ultimately, the change in solar activity can affect climate change, On the growth of wood, mass appearance of forest pests and crops, reproduction of rodents, fishing fish, etc. With periodic activities of the Sun are associated with many human diseases (cardiovascular, neuropsychic, viral, etc.).

Around the Sun, according to the laws of heavenly mechanics, eight large planets are moving: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.

In accordance with the laws of I.Kepler, firstly, each planet is drawn by an ellipse, in one of the focus of which the sun is; Secondly, the radius-vector of the planet for equal intervals describes equal areas (i.e. near the sun, the planet is moving faster than away from it); Thirdly, the ratio of the cubes of large semi-axes of the orbits of the two any planets of the solar system is equal to the ratio of the squares of their appeals around the Sun.

The movement of the planets is subordinated by the law of world-wide, open by I.Nutonon. According to this law, all bodies interact with force with force, directly proportional to the product of their masses and the backdrop-republication square of the distance between them:

F \u003d f ---------, where f -Pered the value, M 1 and M 2 - the masses of the two

existing bodies, R is the distance between them.

According to its size and physicochemical properties of the planet, the planets are divided into two groups: 1) the planet "Earth" group (Mercury, Venus, Earth, Mars) have relatively small sizes, a relatively short period of circulation around the Sun, have a high density of the substance (from 4, 0 to 5.5 g / cm 3); 2) Planets-Giants (Jupiter, Saturn, Uranus, Neptune) have a giant dimensions, low density (1.3-1.6 g / cm 3), the same type chemical composition And a large number of satellites. Pluto should be attributed to the third group, because In terms of its size, he adjoins the "earthly" group planets, and in physical and chemical properties it is brought together with the giants planets. Probably, the orbit of Pluto can exist other bodies whose orbits are strongly elongated ellipses.

In relation to the Earth orbit, the planet also shall be divided into two groups: 1) Internal (Mercury, Venus) are always near the sun and therefore they can be observed in the sky or in the East before sunrise, or in the west after it comes; 2) Outdoor (Mars, Jupiter, Saturn, Uranus, Neptune, only the first three are visible to the naked eye, the rest can only be observed in a telescope.

Mercury - The planet is the closest to the Sun (the distance of nearly 58 million km or 0.4 AE). The period of treatment around the Sun is 88 days. The atmosphere is strongly resolved (practically no, because the strength of gravity is small and cannot hold the gas shell). Temperature on the sunny side +400 ° C (at night below -100 ° C). The surface resembles the lunar landscape, because Strongly "exist" by crater.

Venus - The closest planet to Earth, its size is almost the same as the earth (the diameter of Venus is about 12,112 km). Distance from the Sun to Venus 108 million km (0.7 AE); The period of circulation is 225 days. Venus has a powerful atmosphere consisting of carbon dioxide (97%), nitrogen, inert gases, etc. Carbon dioxide and water vapor (0.1%) create a greenhouse effect, resulting in a temperature on Venus almost +500 o C. The surface of the planet Always hidden from observers with a dense layer of clouds.

Land - the third planet from the sun (the distance to the Sun is approximately 150 million km, or 1 AE). The average diameter of the Earth is about 12,742 km; The period of appeal around the Sun is 1 year. The land has 1 satellite - the moon. (For details, see the chapter "The Characteristics of the Earth as the Planet").

Mars - The fourth planet from the sun (the distance to the Sun is about 228 million km, or 1.5 A.; the circulation period is approximately 2 years). On the diameter of Mars twice the ground. Its atmosphere consists of carbon dioxide, argon, etc., its density is smaller than the earth (atmospheric pressure at the surface of Mars is the same as on Earth at an altitude of 35 km). The temperature ranges from +20 ° C to -120 about S. The surface of Mars has a reddish tint, and the poles are visible white caps (probably from frozen carbon dioxide). Since Mars has an axis tilt the same as the land, then it is well expressed a change of seasons (melting "caps"). Mars has two satellites: Phobos and Dimimos.

Jupiter - The largest planet in the solar system. The distance to the Sun is 780 million km (5 AE), the circulation period is approximately 12 years. The diameter of Jupiter is 11 times longer than the diameter of the Earth. Because of the rapid rotation around its axis, Jupiter is strongly compressed from the poles. The atmosphere of it consists of hydrogen, helium, methane, ammonia. Temperature -140 o S. Jupiter has a system of small rings and 16 satellites (IO, Europe, Callisto, Ganymed, etc.), and the Gamornad and Callisto in size exceed the Mercury Planet.

Saturn - The second largest planet in the solar system. The distance to the Sun is 1 billion 430 million km (10 AE), the period of circulation is about 30 years. The atmosphere of gases is close to the atmosphere of Jupiter; Temperature -170 About S. Saturn has a rings system (external, medium, internal). Rings are not solid, they are a totality of bodies rotating around the planet. Saturn has 18 satellites (Titan, Janus, Reya, etc.).

Uranus - The seventh of the sun planet (the distance to the Sun is 2 billion 869 million km, or 19 AE; the circulation period of approximately 84 years). The atmosphere is similar to the atmospheres of other planets-giants, the temperature -215 o C. Uranus has a system of small rings and 17 satellites (Ariel, etc.).

Neptune It is at a distance of 4 billion 497 million km from the Sun (30 AE), the period of its appeal is 165 years. In terms of size and physical conditions, Neptune is close to uranium. It has 11 satellites (Triton, Neret, etc.).

Besides big planets, around the sun moving and small planets - asteroids . They form an independent belt between the orbits of Mars and Jupiter. Asteroids do not have a certain form, but are angular boulders or debris. It is likely that these are fragments of a small destroyed planet. Their orbits are enough elliptic. The major asteroids are known about 2000 (Ceres, Vesta, Pallada, Juno, etc.), and their total number of more than 60 thousand.

Comet (Translated from Greek means tailed). Most comet moves around the Sun along the strongly elongated elliptical orbits. According to the hypothesis of the Dutch Scientist Oort, a bunch of substances remained on the outskirts of the solar system, from which comets were formed ("Oort Cloud"). Some comets are aliens from space, their orbits are parabolas and hyperboles. Comets have the appearance of foggy objects with a luminous core in the center and tail, the length of which increases with the comet approaches to the Sun. Consist the comet from the fatty stones and gases (CO, CO 2, N 2, CH, etc.). When approaching the Sun around the Kernel comet is formed, a gas shell is formed (a head that can be the size of the sun) and the tail - evaporating gases (tail length can reach tens million km). The most famous comet of Halley with the period of circulation around the Sun is 76 years old (the last time it passed near the Earth in 1986. At the end of March 1996, a comet was passed near the Earth, which was visible to the naked eye. In 1997, in March-April, Khyla's comet was observed -Poppa. This comet was opened in July 1995 by American scientists A. Höhil and T. Bopep. It turned out that this comet has an elliptical orbit with a period of about 3,000 years. On March 23, 1997, the comet passed by the Earth at a distance of 195 million. km, at this time brilliance comet reached the maximum. Thus, at the end of March - early April 1997, Khyla-Bopp comet was also clearly visible in heaven.

Meteoric bodies - These are meteorites and meteors. Meteorites are bodies coming from the interplanetary space, they fall out in the form of fragments. Large meteorites are called cars. It is believed that meteorites are fragments of asteroids. Meteors are the smallest solid particles that invadant to the atmosphere of the Earth (observed in the form of "falling" stars). Their origin is associated with the swollen nuclei comet. Especially many meteors appear every year in early January, late April, mid-August and mid-November ("Meteoric rains"). During the year, several tons of meteorite substance falls on the ground.

On March 13, 1781, the English astronomer William Herschel opened the seventh planet of the Solar System - Uranus. And on March 13, 1930, American astronomer Clyde Tombo opened the ninth planet of the Solar System - Pluto. By the beginning of the XXI century it was believed that the solar system includes nine planets. However, in 2006, the International Astronomical Union decided to deprive the Pluton of this status.

There are already 60 natural satellites of Saturn, most of which are detected using spacecraft. Most of the satellites consists of rock and ice. The largest satellite - Titan, opened in 1655 by Christian Guigens, is superior to the Mercury Planet. Titanium diameter is about 5,200 km. Titan flies around Saturn every 16 days. Titan is the only satellite with a very dense atmosphere, 1.5 times more terrestrial, and consisting mainly of 90% nitrogen, with moderate methane content.

The International Astronomical Union officially recognized Pluto Planet in May 1930. At that moment, it was assumed that his mass is comparable to the mass of the earth, but later it was found that the mass of the pluto is almost 500 times less than the earth, even less than the mass of the moon. Mass of Pluto 1.2 per 10 B22 degree kg (0.22 mass of the Earth). The average distance of Pluto from the Sun 39.44 AE. (5.9 at 10 B12 degrees of the CM), the radius of about 1.65 thousand km. The period of circulation around the Sun is 248.6 years, the period of rotation around its axis is 6.4 days. Pluto composition presumably includes stone and ice; The planet has a thin atmosphere consisting of nitrogen, methane and carbon monofilament. Pluto has three satellites: Charon, Hydra and Nikta.

At the end of the XX and early XXI centuries, many objects were opened in the outside of the solar system. It became obvious that Pluto is just one of the largest objects known to the present objects of the Kuiper belt. Moreover, at least one of the objects of the belt - Erid is a larger body than Pluto and 27% harder. In this regard, the idea arose not to consider more Pluto as a planet. On August 24, 2006, at the XXVI General Assembly of the International Astronomical Union (MAC), it was decided to call Pluto not "planet", but a "dwarf planet".

The conference was developed by a new definition of the planet, according to which the planets are considered to be the bodies rotating around the star (and not the star), having a hydrostatically equilibrium form and the "clearing" region in the area of \u200b\u200btheir orbit from other, smaller, objects. The dwarf planets will be considered objects rotating around the stars having a hydrostatically equilibrium form, but not "clearing" nearby space and non-satellites. Planets and dwarf planets are two different classes of solar system objects. All other objects rotating around the Sun and are not satellites, will be called small bodies of the solar system.

Thus, since 2006, eight planets were in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. Five dwarf planets are officially recognized by the International Astronomical Union: Ceres, Pluto, Haumet, Mchamak, Erida.

On June 11, 2008, Mas declared the introduction of the concept of "Plotoid". Plutoids decided to call the heavenly bodies, turning around the Sun in orbit, the radius of which is more than the radius of the orbit of Neptune, the mass of which is sufficient so that the gravitational forces gave them almost a spherical shape, and which do not clear the space around their orbits (that is, there are many small objects around them. ).

Because for such distant objects as Plodoids, to determine the form and thus attitude to the class of dwarf planets is still difficult, scientists recommended all objects temporarily to plotoids, the absolute asteroid value of which (gloss from a distance of one astronomical unit) is brighter +1. If it is later clear that the objective planet is not considered to Plotoids, it is deprived of this status, although the assigned name will be left. Plotoids include dwarf planets Pluto and Erid. In July 2008, Mchamak was included in this category. September 17, 2008 Hawmea added list.

Material prepared on the basis of open sources information

From the surface to the kernel: eight travels to the depths of the planets of the solar system.

Eight planets of our solar system are made to divide on the internal (Mercury, Venus, Earth, Mars), located closer to the star, and external (Jupiter, Saturn, Uranus, Neptune). They differ not only to the distance to the Sun, but also a number of other characteristics. Interior planets - dense and stony, small sizes; External - gas giants. Internal quite a bit of natural satellites, or not at all; There are dozens of their external, and Saturn also has rings.

Comparative dimensions of the planets (from left to right: Mercury, Venus, Earth, Mars)

NASA.

The basic "anatomy" of the internal planets of the solar system is simple: all of them consist of bark, mantle and kernel. In addition, some kernel are divided into inner and external. For example, how is the earth? The solid bark covers a semi-plane mantle, and in the center there is a "two-layer" kernel - liquid external and solid internal. By the way, it is the presence of a liquid metal core creates a global magnetic field on the planet. On Mars, for example, everything is a bit otherwise: the solid bark, solid mantle, solid core - it resembles a one-piece billiard ball, and no magnetic field He has no.

Gaza giants - Saturn and Jupiter - are folded completely differently. From the very name of this type of planets it is clear that they are huge gas balls that do not have a solid surface. If anyone happened to descend one of these planets, he would fall and fell to her center, where a small solid core is located. In uranium and neptune, ammonia, methane and other familiar gases can exist only in solid form, so two distant planets are huge balls from ice and solid fragments - ice giants. However, let's consider them all in order, one after another.

Mercury: a huge core

The closest planet to the sun is one of the most dense on our list: being a little less satellite Saturn Titan, it is more than twice as harder. Mercury is only the Earth only, but the Earth is large enough to ensure that its own gravity also compacted, and if this effect did not appear, then Mercury would be a champion.

A heavy iron and nickel kernel reigns here. It is extremely large for the planet of such sizes - according to some assumptions, the kernel can occupy the bulk of Mercury volume and have a radius of about 1800-1900 km, approximately with the moon. But the surrounding silicon mantle and bark are relatively thin, no more than 500-600 km in thickness. Judging by the fact that the planet rotates slightly unevenly (as a raw egg), the kernel is melted and creates a global magnetic field on the planet.

The origin of a large, dense, extremely rich iron core of Mercury remains a mystery. Perhaps once Mercury was several times larger, and his kernel was not something abnormal, but as a result of a collision with an unknown body "fell off" a fair piece of bark and mantle. Unfortunately, it is not yet possible to confirm this theory.

1. Bark, thickness - 100-300 km. 2. Mantle, thickness - 600 km. 3. The kernel, radius - 1800 km.

Joel Holdsworth.

Venus: Fat Bark

The most restless and hot planet of the solar system. Its extremely dense and stormy atmosphere consists of carbon dioxide, methane and hydrogen sulfide, which emit numerous active volcanoes. The surface of Venus is 90% covered with basalt lava, there are extensive hills on the manner of earthly mainland - it is a pity that water in liquid form cannot exist here, she has long evaporated.

The inner structure of Venus is well studied. It is believed that its thick silicate bark goes deep into a few tens of kilometers. Judging by some data, 300-500 million years ago, the planet completely updated the bark as a result of the catastrophic amounts of volcanism. It is assumed that heat that is produced in the depths of the planet due to radioactive decay, can not gradually on Venus, as on Earth, by means of slab tectonics. Tectonics plates are not here, and this energy is accumulated for a long time, and from time to time "breaks through" such global volcanic "storms".

Under the bark of Venus begins a 3000-kilometer layer of molten melt of an unidentified composition. And once Venus applies to the same type of planets as the Earth, it is supposed to also have an iron-nickel nucleus with a diameter of about 3000 km. On the other hand, observations did not discovery from Venus of their own magnetic field. This may mean that the charged particles are not moving in the kernel, and it is in a solid state.

Possible inner structure of Venus

Wikimedia / VZB83.

Earth: everything is perfect

Our favorite native planet has been studied, of course, the best of all, including geologically. If you move from its surface to the depth, the solid bark will reach up to about 40 km. The continental and ocean bark are sharply different: the thickness of the first can reach up to 70 km, and the second is almost no more than 10 km. The first contains many volcanic rocks, the second is covered with a thick layer of sediment.

The bark, as a cracked dry dirt, is divided into lithospheric plates moving relative to each other. Judging by modern data, the tactics of the plates - the phenomenon is unique in the solar system, which ensures constant and noncatastrophic, as a whole, the calm update of its surface. Very convenient for everyone!

The layers of mantle begins below: the upper (40-400 km), the lower (up to 2700 km). The mantle accounts for the lion's share of the mass of the planet - almost 70%. In terms of the volume of the mantle is still impressive: if not considered the atmosphere, it takes about 83% of our planet. The composition of the mantle is likely to resemble the composition of stony meteorites, it is rich in silicon, iron, oxygen, magnesium. Despite the constant mixing, you should not consider the mantle of liquid in the usual understanding of this word. Due to the huge pressure, almost all of its substance is in the crystalline state.

Finally, we will fall into the iron-nickel kernel: molten external (at a depth of 5100 km) and solid internal (up to 6400 km). The kernel accounts for almost 30% of the mass of the Earth, and the convection of the liquid metal in the external core creates a global magnetic field on the planet.

General structure of the planet Earth

Wikimedia / Jeremy Kemp

Mars: Frozen Plates

Although Mars himself is noticeably less than the Earth, it is interesting that its surface area is approximately equal to the area of \u200b\u200bthe earth sushi. But the height differences are much more significant: on the red planet there are the highest in the solar mountain system. Local Everest - Mons Olympus - rises to a height of 24 km, and huge mountain ranges above 10 km can reach thousands of kilometers.

Basalt planet bark covered in the northern hemisphere has a thickness of about 35 km, and in South - already up to 130 km. It is believed that once on Mars also there was a movement of lithospheric plates, but from some moment they stopped. Because of this, volcanic dots ceased to change their location, and volcanoes began to grow and grow hundreds of millions of years, creating exceptionally mighty mountain peaks.

The average density of the planet is quite small - apparently, due to the small size of the nucleus and the presence of a considerable element in it (up to 20%) in it - say, sulfur. Judging by the data available, the kernel of Mars has a radius of about 1500-1700 km and remains liquid only partially, and therefore it is capable of creating on the planet only a very weak magnetic field.

Comparison of the structure of Mars and other planets of the earth group

NASA.

Jupiter: gravity and light gases

Today there is no technical opportunity to explore the structure of Jupiter: this planet is too great, its gravity is too strong, the atmosphere is too tight and restless. However, where the atmosphere ends here and the planet itself begins, it is difficult to say: this gas giant, in fact, has no clear inner borders.

According to existing theories, in the center of Jupiter there is a solid core by weight of 10-15 times more land and one and a half times larger in size. However, on the background of the planet-giant (the mass of Jupiter is greater than the mass of all the other planets of the solar system combined) this value is completely insignificant. In general, the Jupiter consists of 90% of conventional hydrogen, and for the remaining 10% from helium, with some simple hydrocarbons, nitrogen, sulfur, oxygen. But do not think that because of this, the structure of the gas giant "is simple".

In colossal pressure and temperature, hydrogen (and according to some data, and helium) should exist here, mainly in an unusual metal form - this layer may stretch to a depth of 40-50 thousand km. Here the electron breaks away from the proton and begins to behave freely as in metals. Such liquid metal hydrogen is naturally an excellent conductor and creates an exceptionally powerful magnetic field on the planet.

Model of the internal structure of Jupiter

NASA.

Saturn: self-heating system

Despite all the external differences, the lack of the famous red spots and the presence of even more famous rings, Saturn is very similar to the nearby Jupiter. It consists of 75% hydrogen, and 25% of helium, with a trace amount of water, methane, ammonia and solids, mainly focused in the hot core. As with Jupiter, there is a thick layer of metallic hydrogen, creating a powerful magnetic field.

Perhaps the main difference between the two gas giants are warm subsystem of Saturn: the processes in the depth supply the planet is already more energy than solar radiation - it emits 2.5 times more energy himself than getting from the sun.

These processes, apparently, two (we note that they also work on Jupiter, simply on Saturn have a greater value) - radioactive decay and the Kelvin - Helmholtz mechanism. The work of this mechanism can be presented quite easily: the planet is cooled, the pressure in it drops, and it is slightly compressed, and the compression creates additional heat. However, it is impossible to exclude other effects of energy in the depths of Saturn.

The inner structure of Saturn

Wikimedia.

Uranus: ice and stone

But in uranium internal heat is clearly not enough, and so much that it still requires a special explanation and puzzles scientists. Even Neptune, the uranium is very similar, radiates warm times more, the uranue is not enough that it gets completely a bit from the Sun, and gives about 1% of this energy. This is the coldest planet of the solar system, the temperature here can fall to 50 Kelvin.

It is believed that the bulk of uranium is accounted for a mixture of ice - water, methane and ammonia. It is half less by weight here hydrogen with helium, and even less solid rocks, most likely focused in a relatively small stone core. The main share falls on an ice mantle. True, this ice is not exactly the substance to which we are accustomed to, he is tech and carnal.

This means that the ice giant also does not have any solid surface: a gaseous, consisting of hydrogen and helium atmosphere without an obvious border goes into liquid upper layers of the planet itself.

The internal structure of uranium

Wikimedia / Francescoa.

Neptune: Diamond rain

As with uranium, Neptune the atmosphere is especially noticeable, it is 10-20% of the entire mass of the planet and extends 10-20% of the distance to the nucleus in its center. It consists of hydrogen, helium and methane, which gives the planet bluish color. Running deep into it, we note that the atmosphere is gradually compacted, slowly moving into a liquid and hot electrically conductive mantle.

Neptune Mantle is ten times heavier than our Earth and is rich in ammonia, water, methane. It is really hot - the temperature can reach thousands of degrees - but traditionally the substance is called ice, and Neptune, as well as uranium belongs to the ice giants.

There is a hypothesis, according to which the pressure is closer to the nucleus and the temperature reaches such a value that methane "scatters" and "sucks" into diamond crystals, which at a depth of 7,000 km form the ocean of "diamond liquid", which is shedding "rains" to the core of the planet. The iron-nickel nucleus of Neptune is rich in silicates and only a little more terrestrial, although the pressure in the central regions of the giant is much higher.

1. Upper atmosphere, upper clouds 2. The atmosphere consisting of hydrogen, helium and methane 3. Mantle consisting of water, ammonia and methane ice 4. Iron-nickel kernel

Naked Science.

http://naked-science.ru/article/nakedScience/kak-ustroeny-planety.