Planets of the solar system: eight and one. The internal structure of the earth

Planet characteristics:

Distance from the Sun: 149.6 million km
Planet Diameter: 12,765 km
Days on the planet: 23h 56min 4s*
Year on the planet: 365 days 6h 9m 10s*
t° on the surface: average for the planet +12°C (In Antarctica up to -85°C; in the Sahara desert up to +70°C)
Atmosphere: 77% Nitrogen; 21% oxygen; 1% water vapor and other gases
Satellites: Moon

* period of rotation around its own axis (in Earth days)
** orbital period around the Sun (in Earth days)

From the very beginning of the development of civilization, people were interested in the origin of the Sun, planets and stars. But most of all, the planet that is our common home, the Earth, arouses interest. Ideas about it changed along with the development of science, the very concept of stars and planets, as we understand it now, was formed only a few centuries ago, which is negligible compared to the very age of the Earth.

Presentation: planet Earth

The third planet from the Sun, which has become our home, has a satellite - the Moon, and is included in the group of terrestrial planets such as Mercury, Venus and Mars. The giant planets differ significantly from them in physical properties and structure. But even such a tiny planet in comparison with them, like the Earth, has an incredible mass in terms of comprehension - 5.97x1024 kilograms. It revolves around the star in an orbit at an average distance from the Sun of 149 million kilometers, rotating around its axis, which causes the change of days and nights. And the ecliptic of the orbit itself characterizes the seasons.

Our planet plays a unique role in the solar system, because the Earth is the only planet that has life! The Earth is located in an extremely successful way. It travels in orbit at a distance of almost 150,000,000 kilometers from the Sun, which means only one thing - Earth is warm enough for water to remain in liquid form. Under the condition of hot temperatures, the water would simply evaporate, and in the cold it would turn into ice. Only on Earth is there an atmosphere in which humans and all living organisms can breathe.

History of the origin of the planet Earth

Starting from the Big Bang Theory and based on the study of radioactive elements and their isotopes, scientists have found out that the approximate age of the earth's crust is about four and a half billion years, and the age of the Sun is about five billion years. Just like the entire galaxy, the Sun was formed as a result of gravitational compression of a cloud of interstellar dust, and after the luminary, the planets included in the solar system were formed.

As for the formation of the Earth itself as a planet, its very birth and formation lasted hundreds of millions of years and took place in several phases. At the birth phase, obeying the laws of gravity, a large number of planetesimals and large cosmic bodies fell on its ever-growing surface, which subsequently constituted almost the entire modern mass of the earth. Under the influence of such a bombardment, the planet's substance was heated and then melted. Under the influence of gravity, heavy elements such as ferrum and nickel formed the core, and lighter compounds formed the earth's mantle, the crust with continents and oceans lying on its surface, and an atmosphere that was originally very different from the present.

The internal structure of the earth

Of the planets of its group, the Earth has the largest mass and therefore has the largest internal energy - gravitational and radiogenic, under the influence of which processes in the earth's crust are still ongoing, as can be seen from volcanic and tectonic activity. Although igneous, metamorphic and sedimentary rocks have already formed, forming the outlines of landscapes, which are gradually modified under the influence of erosion.

Under the atmosphere of our planet is a solid surface called the earth's crust. It is divided into huge pieces (slabs) of solid rock, which can move and, when moving, touch and push each other. As a result of this movement, mountains and other features of the earth's surface appear.

The earth's crust is 10 to 50 kilometers thick. The crust "floats" on the liquid earth's mantle, the mass of which is 67% of the mass of the entire Earth and extends to a depth of 2890 kilometers!

The mantle is followed by the outer liquid core, which extends into the depths for another 2260 kilometers. This layer is also mobile and is capable of emitting electric currents, which create the planet's magnetic field!

At the very center of the Earth is the inner core. It is very hard and contains a lot of iron.

Atmosphere and surface of the Earth

Earth is the only one of all the planets in the solar system that has oceans - they cover more than seventy percent of its surface. Initially, water in the atmosphere in the form of steam played a large role in the formation of the planet - the greenhouse effect raised the temperature on the surface by those tens of degrees necessary for the existence of water in the liquid phase, and in combination with solar radiation gave rise to photosynthesis of living matter - organic matter.

From space, the atmosphere appears to be a blue border around the planet. This thinnest dome consists of 77% nitrogen, 20% oxygen. The rest is a mixture of various gases. The Earth's atmosphere contains much more oxygen than any other planet. Oxygen is vital for animals and plants.

This unique phenomenon can be regarded as a miracle or considered an incredible coincidence. It was the ocean that gave rise to the birth of life on the planet, and, as a result, the emergence of Homo sapiens. Surprisingly, the oceans still hold many secrets. Developing, humanity continues to explore space. Entering the near-Earth orbit made it possible to comprehend in a new way many geoclimatic processes occurring on Earth, further study of the secrets of which is yet to be done by more than one generation of people.

Earth Satellite - Moon

The planet Earth has its only satellite - the Moon. The first to describe the properties and characteristics of the Moon was the Italian astronomer Galileo Galilei, he described the mountains, craters and plains on the surface of the Moon, and in 1651 the astronomer Giovanni Riccioli mapped the visible side of the lunar surface. In the 20th century, on February 3, 1966, the Luna-9 descent module landed on the Moon for the first time, and a few years later, on July 21, 1969, a human foot set foot on the Moon for the first time.

The moon is always turned to the planet Earth with only one of its sides. On this visible side of the Moon, flat "seas", chains of mountains and multiple craters of various sizes are visible. The other side, invisible from the Earth, has on the surface a large cluster of mountains and even more craters, and the light reflecting from the Moon, thanks to which we can see it at night in a pale lunar color, is weakly reflected rays from the Sun.

The planet Earth and its satellite the Moon are very different in many properties, while the ratio of stable oxygen isotopes for the planet Earth and its satellite the Moon is the same. Conducted radiometric studies have shown that the age of both celestial bodies is the same, approximately 4.5 billion years. These data give rise to the assumption that the Moon and the Earth originated from the same substance, which gives rise to several interesting hypotheses about the origin of the Moon: from the origin from the same protoplanetary cloud, the capture of the Moon by the Earth, and to the formation of the Moon from the collision of the Earth with a large object.

Earth is the third planet in the solar system. Find out the description of the planet, mass, orbit, size, interesting facts, distance to the Sun, composition, life on Earth.

Of course we love our planet. And not only because it is a home, but also because it is a unique place in the solar system and the universe, because so far we know only life on Earth. It lives in the inner part of the system and occupies a place between Venus and Mars.

planet earth also called the Blue Planet, Gaia, the World and Terra, which reflects its role for each people in historical terms. We know that our planet is rich in many different life forms, but how exactly did it manage to become so? First, consider interesting facts about the Earth.

Interesting facts about planet Earth

Rotation gradually slows down

For earthlings, the entire process of slowing down the rotation of the axis occurs almost imperceptibly - 17 milliseconds per 100 years. But the nature of the speed is not uniform. This results in an increase in the length of the day. After 140 million years, a day will cover 25 hours.

The earth was believed to be the center of the universe

Ancient scientists could observe celestial objects from the position of our planet, so it seemed that all objects in the sky were moving relative to us, and we remained at one point. As a result, Copernicus declared that the Sun (the heliocentric system of the world) is at the center of everything, although now we know that this does not correspond to reality, if we take the scale of the Universe.

Endowed with a powerful magnetic field

The earth's magnetic field is created by the nickel-iron planetary core, which is rapidly rotating. The field is important because it protects us from the influence of the solar wind.

Has one companion

If you look at the percentage, then the Moon is the largest satellite in the system. But in reality it is in the 5th position in size.

The only planet not named after a deity

Ancient scientists named all 7 planets in honor of the gods, and modern scientists, when discovering Uranus and Neptune, followed the tradition.

First in Density

Everything is based on the composition and specific part of the planet. So the core is represented by metal and bypasses the crust in density. The average earth density is 5.52 grams per cm 3.

Size, mass, orbit of the planet Earth

With a radius of 6371 km and a mass of 5.97 x 10 24 kg, the Earth is in the 5th position in terms of size and massiveness. This is the largest terrestrial planet, but it is inferior in size to the gas and ice giants. However, in terms of density (5.514 g / cm 3) it ranks first in the solar system.

polar contraction	0,0033528
Equatorial	6378.1 km
Polar radius	6356.8 km
Medium radius	6371.0 km
Great circle circumference	40,075.017 km (equator) (meridian)
Surface area	510,072,000 km²
Volume	10.8321 10 11 km³
Weight	5.9726 10 24 kg
Average density	5.5153 g/cm³
Acceleration free fall at the equator	9.780327 m/s²
first cosmic speed	7.91 km/s
Second space velocity	11.186 km/s
equatorial speed rotation	1674.4 km/h
Rotation period	(23 h 56 m 4,100 s)
Axis Tilt	23°26’21",4119
Albedo	0.306 (Bond) 0.367 (geom.)

A weak eccentricity (0.0167) is observed in the orbit. The distance from the star at perihelion is 0.983 AU, and at aphelion it is 1.015 AU.

It takes 365.24 days to go around the Sun. We know that due to the existence of a leap year, we add a day every 4 passes. We used to think that a day lasts 24 hours, in reality this time takes 23 hours 56 meters and 4 seconds.

If you observe the rotation of the axis from the poles, you can see that it occurs counterclockwise. The axis is tilted 23.439281° from the perpendicular to the orbital plane. This affects the amount of light and heat.

If the North Pole is turned towards the Sun, then summer is set in the northern hemisphere, and winter is set in the south. At a certain time, the Sun does not rise at all over the Arctic Circle, and then night and winter last there for 6 months.

The composition and surface of the planet Earth

In shape, the planet Earth resembles a spheroid, oblate at the poles and with a bulge on the equatorial line (diameter - 43 km). This is due to rotation.

The structure of the Earth is represented by layers, each of which has its own chemical composition. It differs from other planets in that our core has a clear distribution between the solid inner (radius - 1220 km) and the liquid outer (3400 km).

Next comes the mantle and bark. The first deepens to 2890 km (the densest layer). It is represented by silicate rocks with iron and magnesium. The crust is divided into the lithosphere (tectonic plates) and the asthenosphere (low viscosity). You can carefully consider the structure of the Earth in the diagram.

The lithosphere breaks up into solid tectonic plates. These are rigid blocks that move relative to each other. There are points of connection and break. It is their contact that leads to earthquakes, volcanic activity, the creation of mountains and ocean trenches.

There are 7 main plates: Pacific, North American, Eurasian, African, Antarctic, Indo-Australian and South American.

Our planet is remarkable in that approximately 70.8% of the surface is covered with water. The bottom map of the Earth shows tectonic plates.

The earth landscape is different everywhere. The submerged surface resembles mountains and features underwater volcanoes, oceanic trenches, canyons, plains, and even oceanic plateaus.

During the development of the planet, the surface was constantly changing. Here it is worth considering the movement of tectonic plates, as well as erosion. The transformation of glaciers, the creation of coral reefs, meteorite impacts, etc. also affect.

The continental crust is represented by three varieties: magnesium rocks, sedimentary and metamorphic. The first is divided into granite, andesite and basalt. Sedimentary is 75% and is created during the disposal of accumulated sediment. The latter is formed during icing of sedimentary rock.

From the lowest point, the surface height reaches -418 m (on the Dead Sea) and rises to 8848 m (the summit of Everest). The average height of land above sea level is 840 m. The mass is also divided between hemispheres and continents.

The outer layer contains soil. This is a kind of line between the lithosphere, atmosphere, hydrosphere and biosphere. Approximately 40% of the surface is used for agricultural purposes.

Atmosphere and temperature of planet Earth

There are 5 layers of the earth's atmosphere: troposphere, stratosphere, mesosphere, thermosphere and exosphere. The higher you go, the less air, pressure and density you will feel.

Closest to the surface is the troposphere (0-12 km). It contains 80% of the mass of the atmosphere, with 50% located within the first 5.6 km. Consists of nitrogen (78%) and oxygen (21%) with impurities of water vapor, carbon dioxide and other gaseous molecules.

In the interval of 12-50 km we see the stratosphere. It is separated from the first tropopause - a feature with relatively warm air. This is where the ozone layer is located. The temperature rises as the interlayer absorbs ultraviolet light. The atmospheric layers of the Earth are shown in the figure.

It is a stable layer and virtually free from turbulence, clouds and other weather formations.

At an altitude of 50-80 km is the mesosphere. This is the coldest place (-85°C). It is located near the mesopause, which extends from 80 km to the thermopause (500-1000 km). The ionosphere lives within 80-550 km. Here the temperature rises with altitude. In the photo of the Earth you can admire the northern lights.

The layer is devoid of clouds and water vapor. But it is here that the auroras are formed and the International Space Station (320-380 km) is located.

The outermost sphere is the exosphere. This is a transitional layer to outer space, devoid of atmosphere. Represented by hydrogen, helium and heavier molecules with low density. However, the atoms are so widely dispersed that the layer does not behave like a gas, and the particles are constantly escaping into space. Most of the satellites live here.

This score is influenced by many factors. The Earth makes an axial rotation in 24 hours, which means that one side always experiences night and lower temperatures. In addition, the axis is tilted, so the northern and southern hemispheres take turns deviating and approaching.

All this creates seasonality. Not every part of the earth experiences sharp drops and rises in temperatures. For example, the amount of light entering the equatorial line remains virtually unchanged.

If we take the average, we get 14 ° C. But the maximum is 70.7°C (Lut Desert), and the minimum of -89.2°C was reached at the Soviet station Vostok on the Antarctic Plateau in July 1983.

Moon and Earth's asteroids

The planet has only one satellite, which affects not only the physical changes of the planet (for example, tides), but also reflected in history and culture. To be precise, the Moon is the only celestial body on which a person walked. It happened on July 20, 1969, and Neil Armstrong got the first step. Generally speaking, 13 astronauts landed on the satellite.

The moon appeared 4.5 billion years ago due to the collision of the Earth and a Martian-sized object (Theia). You can be proud of our satellite, because it is one of the largest moons in the system, and also ranks second in density (after Io). It is in a gravitational lock (one side always faces the Earth).

It covers 3474.8 km in diameter (1/4 of the Earth's), and its mass is 7.3477 x 10 22 kg. The average density is 3.3464 g/cm 3 . According to gravity, it reaches only 17% of the earth. The moon affects the earth's tides, as well as the activity of all living organisms.

Do not forget that there are lunar and solar eclipses. The first happens when the Moon enters the Earth's shadow, and the second happens when a satellite passes between us and the Sun. The satellite's atmosphere is weak, which causes temperature readings to fluctuate greatly (from -153°C to 107°C).

Helium, neon and argon can be found in the atmosphere. The first two are created by the solar wind, and argon is due to the radioactive decay of potassium. There is also evidence of frozen water in the craters. The surface is divided into different types. There is Maria - flat plains, which ancient astronomers took for the seas. Terras are lands, like highlands. You can even see mountainous areas and craters.

Earth has five asteroids. Satellite 2010 TK7 resides at point L4, and asteroid 2006 RH120 approaches the Earth-Moon system every 20 years. If we talk about artificial satellites, then there are 1265 of them, as well as 300,000 pieces of garbage.

Formation and evolution of the planet Earth

In the 18th century, mankind came to the conclusion that our terrestrial planet, like the entire solar system, emerged from a foggy cloud. That is, 4.6 billion years ago, our system resembled a circumstellar disk, represented by gas, ice and dust. Then most of it approached the center and, under pressure, transformed into the Sun. The remaining particles created the planets known to us.

The primordial Earth appeared 4.54 billion years ago. From the very beginning, it was melted due to volcanoes and frequent collisions with other objects. But 4-2.5 billion years ago, solid crust and tectonic plates appeared. Degassing and volcanoes created the first atmosphere, and ice that arrived on comets formed the oceans.

The surface layer did not remain frozen, so the continents converged and moved apart. Approximately 750 million years ago, the very first supercontinent began to diverge. Pannotia was created 600-540 million years ago, and the last (Pangaea) collapsed 180 million years ago.

The modern picture was created 40 million years ago and fixed 2.58 million years ago. The last ice age, which began 10,000 years ago, is currently underway.

It is believed that the first hints of life on Earth appeared 4 billion years ago (the Archean eon). Due to chemical reactions, self-replicating molecules appeared. Photosynthesis created molecular oxygen, which together with ultraviolet rays formed the first ozone layer.

Further, various multicellular organisms began to appear. Microbial life arose 3.7-3.48 billion years ago. 750-580 million years ago, most of the planet was covered with glaciers. Active reproduction of organisms started during the Cumbrian explosion.

Since that moment (535 million years ago), history has 5 major extinction events. The last (the death of dinosaurs from a meteorite) occurred 66 million years ago.

They were replaced by new species. The African ape-like animal stood up on its hind legs and freed its forelimbs. This stimulated the brain to apply various tools. Further, we know about the development of crops, socialization and other mechanisms that led us to modern man.

Reasons why planet earth is habitable

If the planet meets a number of conditions, then it is considered potentially habitable. Now the Earth is the only lucky one with developed life forms. What is needed? Let's start with the main criterion - liquid water. In addition, the main star must provide enough light and heat to maintain the atmosphere. An important factor is the location in the habitat (the distance of the Earth from the Sun).

You have to understand how lucky we are. After all, Venus is similar in size, but because of its proximity to the Sun, it is a hell of a hot place with acid rain. And Mars behind us is too cold and has a weak atmosphere.

Planet earth research

The first attempts to explain the origin of the Earth were based on religion and myths. Often the planet became a deity, namely a mother. Therefore, in many cultures, the history of everything begins with the mother and the birth of our planet.

The shape is also very interesting. In ancient times, the planet was considered flat, but different cultures added their own characteristics. For example, in Mesopotamia, a flat disk floated in the middle of the ocean. The Maya had 4 jaguars holding the heavens. For the Chinese, it was generally a cube.

Already in the 6th century BC. e. scientists sewed to a round shape. Surprisingly, in the 3rd century BC. e. Eratosthenes even managed to calculate the circle with an error of 5-15%. The spherical shape was fixed with the advent of the Roman Empire. Aristotle spoke about changes in the earth's surface. He believed that this happens too slowly, so a person is not able to catch. This is where attempts to understand the age of the planet arise.

Scientists are actively studying geology. The first catalog of minerals was created by Pliny the Elder in the 1st century AD. In the 11th century in Persia, explorers studied Indian geology. The theory of geomorphology was created by the Chinese naturalist Shen Kuo. He identified marine fossils located far from the water.

In the 16th century, understanding and exploration of the Earth expanded. It is worth thanking the heliocentric model of Copernicus, which proved that the Earth does not act as a universal center (previously they used the geocentric system). And also Galileo Galilei for his telescope.

In the 17th century, geology was firmly entrenched among other sciences. It is said that the term was coined by Ulysses Aldvandi or Mikkel Eschholt. The fossils discovered at that time caused serious controversy in the earth's age. All religious people insisted on 6,000 years (as the Bible said).

These disputes ended in 1785 when James Hutton declared that the Earth was much older. It was based on the blurring of rocks and the calculation of the time required for this. In the 18th century, scientists were divided into 2 camps. The former believed that the rocks were precipitated by floods, while the latter complained about the fiery conditions. Hutton stood in firing position.

The first geological maps of the Earth appeared in the 19th century. The main work is "Principles of Geology", published in 1830 by Charles Lyell. In the 20th century, it became much easier to calculate the age thanks to radiometric dating (2 billion years). However, already the study of tectonic plates has led to a modern mark of 4.5 billion years.

The future of planet Earth

Our life depends on the behavior of the Sun. However, each star has its own evolutionary path. It is expected that in 3.5 billion years it will increase in volume by 40%. This will increase the flow of radiation, and the oceans may simply evaporate. Then plants will die, and in a billion years all living things will disappear, and a constant average temperature will be fixed at around 70 ° C.

In 5 billion years, the Sun will transform into a red giant and shift our orbit by 1.7 AU.

If you look through the entire earth's history, then humanity is just a fleeting flash. However, the Earth remains the most important planet, a native home and a unique place. One can only hope that we will have time to populate other planets outside our system before the critical period of solar development. Below you can explore the map of the Earth's surface. In addition, on our site there are many beautiful photos of the planet and places of the Earth from space in high resolution. With the help of online telescopes from the ISS and satellites, you can observe the planet in real time for free.

Click on the image to enlarge it

On March 13, 1781, English astronomer William Herschel discovered the seventh planet in the solar system - Uranus. And on March 13, 1930, American astronomer Clyde Tombaugh discovered the ninth planet in the solar system - Pluto. By the beginning of the 21st century, it was believed that the solar system included nine planets. However, in 2006, the International Astronomical Union decided to strip Pluto of this status.

There are already 60 known natural satellites of Saturn, most of which have been discovered using spacecraft. Most satellites are made up of rocks and ice. The largest satellite, Titan, discovered in 1655 by Christian Huygens, is larger than the planet Mercury. The diameter of Titan is about 5200 km. Titan orbits Saturn every 16 days. Titan is the only satellite to have a very dense atmosphere, 1.5 times the size of Earth's, and consisting mostly of 90% nitrogen, with a moderate amount of methane.

The International Astronomical Union officially recognized Pluto as a planet in May 1930. At that moment, it was assumed that its mass was comparable to the mass of the Earth, but later it was found that the mass of Pluto is almost 500 times less than the Earth's, even less than the mass of the Moon. The mass of Pluto is 1.2 times 1022 kg (0.22 Earth masses). The average distance of Pluto from the Sun is 39.44 AU. (5.9 by 10 to the 12th degree km), the radius is about 1.65 thousand km. The period of revolution around the Sun is 248.6 years, the period of rotation around its axis is 6.4 days. The composition of Pluto supposedly includes rock and ice; the planet has a thin atmosphere composed of nitrogen, methane and carbon monoxide. Pluto has three moons: Charon, Hydra and Nyx.

In the late 20th and early 21st centuries, many objects were discovered in the outer solar system. It has become clear that Pluto is only one of the largest Kuiper belt objects known to date. Moreover, at least one of the objects of the belt - Eris - is a larger body than Pluto and 27% heavier than it. In this regard, the idea arose to no longer consider Pluto as a planet. On August 24, 2006, at the XXVI General Assembly of the International Astronomical Union (IAU), it was decided to henceforth call Pluto not a "planet", but a "dwarf planet".

At the conference, a new definition of the planet was developed, according to which planets are considered to be bodies revolving around a star (and not being a star themselves), having a hydrostatic equilibrium shape and "clearing" the area in the region of their orbit from other, smaller, objects. Dwarf planets will be considered objects that revolve around a star, have a hydrostatically equilibrium shape, but have not "cleared" the nearby space and are not satellites. Planets and dwarf planets are two different classes of solar system objects. All other objects revolving around the Sun and not being satellites will be called small bodies of the solar system.

Thus, since 2006, there have been eight planets 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, Haumea, Makemake, and Eris.

On June 11, 2008, the IAU announced the introduction of the concept of "plutoid". It was decided to call plutoids celestial bodies that revolve around the Sun in an orbit whose radius is greater than the radius of Neptune's orbit, whose mass is sufficient for gravitational forces to give them an almost spherical shape, and which do not clear the space around their orbit (that is, many small objects revolve around them ).

Since it is still difficult to determine the shape and thus the relation to the class of dwarf planets for such distant objects as plutoids, scientists recommended temporarily assigning to plutoids all objects whose absolute asteroid magnitude (brilliance from a distance of one astronomical unit) is brighter than +1. If it later turns out that the object assigned to the plutoids is not a dwarf planet, it will be deprived of this status, although the assigned name will be left. The dwarf planets Pluto and Eris were classified as plutoids. In July 2008, Makemake was included in this category. On September 17, 2008, Haumea was added to the list.

The material was prepared on the basis of information from open sources

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

Brief information about the planets of the solar system

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

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

Rice. 1. Planets of the solar system.

The list of planets in the solar system in order from the sun is as follows: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. By listing the planets from largest to smallest, this order changes. The largest planet is Jupiter, followed by Saturn, Uranus, Neptune, Earth, Venus, Mars and finally Mercury.

All planets 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 degrees).

Terrestrial planets (inner planets)

The four planets closest to the Sun consist mainly of heavy elements, have a small number of satellites, and have no rings. They are largely composed of refractory minerals such as silicates that form their mantle and crust, and metals such as iron and nickel that form their core. Three of these planets - Venus, Earth and Mars - have an atmosphere.

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

Venus is the hottest planet in our system, with surface temperatures exceeding 400 degrees Celsius. The most likely reason for such a high temperature is the greenhouse effect due to the dense atmosphere rich in carbon dioxide.

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

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

Outer region of the solar system

The outer region of the solar system is the location of the gas giants and their satellites.

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

Rice. 3. Planet Saturn.

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

What have we learned?

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

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