Which planets are considered internal and which are external. The outer planets of the solar system

Questions:

1. How is the name "wandering stars" translated from Greek?

2. Name the inner planets.

3. Which planets are external?

Planet - a solid or solid and gas that revolves around a star.

Even the ancient people in the sky noticed constantly moving stars, and the Greeks called them so "wandering stars" that is, in Greek "planets".
There are nine planets in the solar system: Mercury, Mars, Venus, Earth, Neptune, Uranus, Saturn, Jupiter, Pluto.

Inner planets- Mercury, Mars, Venus, Earth.

The planets belonging to this group are small in size and mass, the average density of these planets is several times higher than the density of water; they slowly revolve around their axes; they have few companions ( Mercury and Venus they don't have them at all, Mars - two, y Earth - one).

The similarity of the terrestrial planets does not exclude some difference. For example, Venus, unlike other planets, rotates in the opposite direction to its movement around the Sun, and is 243 times slower than the Earth.
Circulation period Mercury(i.e., the year of this planet) is only 1/3 longer than the period of its rotation around the axis.
The angles of inclination of the axes to the planes of their orbits y Earthand at Mars approximately the same, but completely different in Mercury and Venus... Same as Earth, there are seasons on Mars, although almost twice as long as Earth.

Similarities and differences are also found in the atmospheres of planets. terrestrial group... Unlike Mercurywhich, like Moon, practically devoid of atmosphere, Venus and Marspossess it.
Venus has a very dense atmosphere, mainly composed of carbon dioxide and sulfur compounds. Atmosphere Mars on the contrary, it is extremely rarefied and also poor in oxygen and nitrogen. Surface pressure Venusalmost 100 times more, while Mars almost 150 times less than the surface Earth.

Outer planets include Neptune, Uranus, Saturn, Jupiter, Pluto.

GIANT PLANETS Jupiter, Saturn, Uranus and Neptune does not at all correspond to our ideas about comfort: it is very cold, terrible gas composition (methane, ammonia, hydrogen, etc.), there is practically no solid surface - only a dense atmosphere and an ocean of liquid gases. All of this is very unlike Earth. However, in the era of the origin of life, the Earth was not at all the same as it is now. Its atmosphere was more like Venusian and Jupiterian, except perhaps warmer. Therefore, in the near future, the search for organic compounds in the atmosphere of the giant planets will certainly be carried out.

The giant planets are far from the Sun, and regardless of the nature of the change of seasons, low dark temperatures always dominate them. On the Jupiterthere is no change of seasons at all, since the axis of this planet is almost perpendicular to the plane of its orbit. The seasons change in a peculiar way on the planet Uranus, since the axis of this planet is inclined to the orbital plane at an angle of 8¦.

The giant planets are distinguished by a large number of satellites; Jupiter has found 16 to date, Saturn - 17, Uranus- 16 and y Neptune - 8. An interesting feature of the giant planets is the rings that were found not only in Saturnbut also Jupiter, Uranus and Neptune.

The most important feature of the structure of giant planets is that these planets have a solid surface. They are composed mainly of light elements - hydrogen and helium.

The solar system is a planetary system that includes the central star - the Sun - and all natural objects in space that revolve around it. It was formed by the 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 characteristics.

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 are mainly composed 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. Largest planets Solar system, Jupiter and Saturn, are composed primarily of hydrogen and helium; the smaller gas giants, Uranus and Neptune, in addition to hydrogen and helium, contain methane and carbon monoxide in their atmospheres.

Figure: 1. Planets of the solar system.

The list of the planets of the solar system in order from the sun looks like this: 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 rotates (counterclockwise when viewed from the North Pole of the Sun).

Mercury has the highest angular velocity - it manages to complete a complete revolution around the Sun in just 88 Earth days. And for the most distant planet - Neptune - the orbital period is 165 Earth years.

Most of the planets revolve around their axis in the same direction as revolve around the Sun. The exceptions are Venus and Uranus, and Uranus rotates practically "lying on its side" (axis tilt about 90 degrees).

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Table. The sequence of the location of the planets in the solar system and their features.

Planet	Distance from the Sun	Circulation period	Rotation period	Diameter, km.	Number of satellites	Density g / cc cm.
Mercury

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 the 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, its surface temperature exceeds 400 degrees Celsius. The most likely reason for such a high temperature is the greenhouse effect arising from a dense atmosphere rich in carbon dioxide.

Figure: 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 planets of the terrestrial group, the Earth is unique (primarily due to the hydrosphere). The 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 terrestrial planets in the solar system.
• Mars - less than Earth and Venus. It possesses an atmosphere composed mainly of carbon dioxide. On its surface there are volcanoes, the largest of which, Olympus, exceeds all earthly volcanoes in size, reaching an altitude of 21.2 km.

Outer region of the solar system

The outer region of the solar system is home to the gas giants and their moons.

• Jupiter - has a mass 318 times that of Earth, and 2.5 times more massive than all other planets combined. It is mainly composed of hydrogen and helium. Jupiter has 67 satellites.
• 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.

Figure: 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 satellites.
• Neptune - the last planet in the solar system. Although slightly smaller than Uranus, it is more massive and therefore more dense. Neptune has 14 known moons.

What have we learned?

One of the fascinating topics of astronomy is the structure of the solar system. We learned what the names of the planets of the solar system are, in what sequence 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 4th grade children.

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The planets of the solar system

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

Pluto was excluded from the category of planets in 2006. since in the Kuiper belt there are objects that are larger / or equal in size to Pluto. Therefore, even if it is taken for 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 groups 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 2,440 km. The period of revolution around the Sun, for ease of understanding, equated to the Earth's year, is 88 days, while Mercury manages to complete a revolution around its own axis only one and a half times. Thus, his day lasts approximately 59 Earth days. For a long time, it was believed that this planet was all the time turned to the Sun by the same side, since the periods of its visibility from the Earth were repeated with a periodicity 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, changing not only the speed of movement and its distance from the Sun, but also the position itself. Anyone interested can observe this effect.

Mercury in color, image from MESSENGER spacecraft

The proximity to the Sun has caused Mercury to experience the largest temperature fluctuations among the planets of our system. The average daytime temperature is about 350 degrees Celsius, and the nighttime temperature is -170 ° C. Sodium, oxygen, helium, potassium, hydrogen and argon were found in the atmosphere. There is a theory that he was previously a satellite of Venus, but so far this remains unproven. He has no satellites of his own.

Venus

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

Venus in the UV spectrum

This atmosphere creates a greenhouse effect, the surface temperature is therefore even higher than that of Mercury and reaches 475 ° C. It is considered the most leisurely, the Venusian day lasts 243 Earth days, which is almost equal to a year on Venus - 225 Earth days. Many call it the sister of the Earth because of its mass and radius, the values \u200b\u200bof which are very close to those of the Earth. 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 have developed. At least life is as we know it. The radius of the Earth is 6371 km and, unlike other celestial bodies of our system, more than 70% of its surface is covered with water. The rest of the space is occupied by continents. Another feature of the Earth is the tectonic plates hidden under the planet's mantle. At the same time, they are able to move, albeit at a very low speed, which over time causes a change in the landscape. The speed of the planet moving along it is 29-30 km / sec.

Our planet from space

One revolution on its axis takes almost 24 hours, and the full orbital passage lasts 365 days, which is much longer in comparison with the nearest neighboring planets. The Earth's day and year are also taken as a standard, but this is done only for the convenience of perception of time intervals on other planets. The Earth has one natural satellite - the Moon.

Mars

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

An illustrative model of the solar system

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• The sun

  The Sun is a star, which is a hot ball of incandescent 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

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

• Venus

  Venus is a world of monstrous heat (even more than on Mercury) and volcanic activity. Similar in structure and size to Earth, Venus is covered 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 have revealed volcanoes and warped 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, atmosphere, 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 believed that the bright and dark areas on Mars were patches of vegetation and that Mars might be a suitable place for life, and that water exists in the polar caps. When the spacecraft Mariner 4 flew off Mars in 1965, many of the scientists were shocked to see photographs of the gloomy planet covered with craters. Mars turned out to be a dead planet. Later missions, however, revealed that Mars holds many mysteries that still remain to be solved.

• Jupiter

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

• Saturn

  Saturn is the farthest of the five planets known before the invention of the telescope. Like Jupiter, Saturn is composed primarily of hydrogen and helium. Its volume is 755 times that of the Earth. Winds in its atmosphere reach speeds of 500 meters per second. These fast winds, combined with the heat rising from the interior of the planet, are causing 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

  The distant Neptune revolves almost 4.5 billion kilometers from the Sun. It takes 165 years for one revolution around the Sun. It is invisible to the naked eye due to its great distance from Earth. It is interesting that its unusual elliptical orbit intersects with the orbit of the dwarf planet Pluto, which is why Pluto is inside the orbit of Neptune for about 20 years out of 248 during which it makes one revolution around the Sun.

• Pluto

  Tiny, cold and incredibly distant, Pluto was discovered in 1930 and has long been considered the ninth planet. But after the discoveries of Pluto-like worlds that were even further away, Pluto was transferred to the category of dwarf planets in 2006.

Planets are giants

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

Planets of the solar system, not scaled

Jupiter

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

It is believed that one of the four gas giants is actually a failed star. This theory is supported by the largest number of satellites, of which Jupiter has many - as many as 67. To imagine their behavior in the planet's orbit, a sufficiently accurate and precise 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 differs in that it is one of three satellites with an atmosphere.

Saturn

The second largest planet and the sixth in the solar system. Compared to other planets, the composition of chemical elements is most similar to the Sun. The surface radius is 57350 km, the year is 10 759 days (almost 30 Earth years). The day here lasts a little longer than on Jupiter - 10.5 Earth hours. By the number of satellites, it is not much behind its neighbor - 62 versus 67. The largest satellite of Saturn is Titan, just like Io, which has an atmosphere. Slightly smaller in size, but no less famous from 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. It has only recently been found that rings are present in all gas giants, but in others they are not so clearly visible. Their origin has not yet been established, although there are several hypotheses about how they came about. In addition, quite recently it was discovered that Rhea, one of the satellites of the sixth planet, also possesses a kind of rings.

The universe is the whole infinite world around us. These are other planets and stars, our planet Earth, its plants and animals, all this is the Universe, including what is outside the Earth- space, planets, stars. This is matter without end and edge, taking on the most diverse forms of its existence. The universe is everything that exists. From the smallest grains of dust and atoms to huge clusters of matter from stellar worlds and stellar systems. The universe, or space, is made up of giant clusters of stars. These huge star systems are called galaxies.

According to modern concepts, the Universe we are now observing arose 13.7 ± 0.2 billion years ago from some initial singular state with gigantic temperature and density, and since then has been continuously expanding and cooling. Recently, scientists have been able to determine that the rate of expansion of the Universe, starting from a certain moment in the past, is constantly increasing, which clarifies some of the concepts of the Big Bang theory.

Big Bang (English Big Bang) is a generally accepted cosmological model that describes the early development of the Universe, namely, the beginning of the expansion of the Universe, before which the Universe was in a singular state. (The word singularity means that this is something incomprehensible to science.)

8. The appearance of elementary particles, gas inhomogeneities, stars of the first generation ...

The universe began with the Big Bang about 15 billion years ago. At that moment, she had a negligible size and an inconceivably high temperature. It expanded and cooled down very quickly. Its original composition - photons (radiation) and quarks - elementary particles, soon followed by heavy subatomic particles - protons and neutrons. As the universe further expanded and cooled, nuclei such as hydrogen and helium emerged from protons and neutrons. Simultaneously with the continued expansion and cooling of the Universe, hydrogen and helium expanded in all directions. Therefore, we can assume that the Universe consisted of a homogeneous cloud of these mixed gases, which became more and more rarefied, filling an ever increasing volume of space as the Universe expanded. However, this cloud did not maintain the same density and did not remain uniform. So, the initially homogeneous mixture of hydrogen and helium thickened over time into huge clouds of gas, separated from each other by almost complete vacuum. These huge in mass and volume gas clouds, which are associated in our view with entire galaxies or with a cluster of galaxies, we could call protogalaxies. In the end, the protogalaxies broke into billions of smaller clouds, between which lay almost empty space. Each gas cloud has its own gravitational field. A very dense gas cloud must have a gravitational field strong enough to cause the cloud to begin to collapse. In other words, having started to contract, the gas cloud continues to contract faster and faster. As it contracts, the pressure and temperature in its center increase. The temperature rises rapidly, and the incandescent cloud begins to glow. Now it is no longer a gas cloud. Before us is a star. The formed galaxies consisted exclusively of hydrogen and helium (mostly hydrogen). The stars formed in them, also having a hydrogen-helium structure, were called "stars of the first generation."

Supernovae - stars ending their evolution in a catastrophic explosive process.

The term “supernovae” was used to describe stars that flared up much (by orders of magnitude) stronger than the so-called “new stars”. In fact, neither one nor the other is physically new, already existing stars always flare up.

9. The solar system, its structure and age

Solar system - planetary system, which includes the central star - the Sun - and all natural space objects orbiting the Sun. It was formed by the gravitational compression of a gas and dust cloud about 4.57 billion years ago.

Most of the mass of objects in the solar system falls on the sun; the rest is contained in eight relatively secluded planets that have almost circular orbits and are located within an almost flat disk - the plane of the ecliptic.

The four smaller inner planets - Mercury, Venus, Earth, and Mars (also called terrestrial planets) - are composed primarily of silicates and metals. The four outer planets - Jupiter, Saturn, Uranus, and Neptune (also called gas giants) - are much more massive than the terrestrial planets. The largest planets in the solar system, Jupiter and Saturn, are composed primarily of hydrogen and helium; the outer, smaller Uranus and Neptune, in addition to hydrogen and helium, contain methane and carbon monoxide in their atmospheres.

There are two regions in the solar system filled with small bodies. The asteroid belt, located between Mars and Jupiter, is similar in composition to the terrestrial planets, since it consists of silicates and metals. The largest objects in the asteroid belt are the dwarf planet Ceres and the asteroids Pallas, Vesta and Hygea. Beyond the orbit of Neptune are trans-Neptunian objects consisting of frozen water, ammonia and methane, the largest of which are Pluto, Sedna, Haumea, Makemake, Kwavar, Ork and Eris. There are other populations of small bodies in the solar system, such as planetary quasi-satellites and Trojans, near-Earth asteroids, centaurs, damocloids, as well as comets, meteoroids and cosmic dust moving through the system.

The solar wind (the flow of plasma from the Sun) creates a bubble in the interstellar medium called the heliosphere, which extends to the edge of the scattered disk. The hypothetical Oort cloud, which is the source of long-period comets, may extend about a thousand times beyond the heliosphere.

The solar system is part of the Milky Way galaxy.

10. Inner and outer planets, their comparative characteristics

Inner planets.

Mercury - one of the smallest non-atmospheric. The surface of Mercury is covered with numerous impact craters up to 1300 km in diameter.

Venus in size and mass it is very close to the Earth, but it rotates in the opposite direction, compared to the rest of the planets. Venus is shrouded in a very dense atmosphere of carbon dioxide, and in the upper layers of sulfuric acid

Mars... This is the fourth planet from the Sun. Mars has a very thin carbon dioxide atmosphere. Low pressure does not allow water to exist, which must evaporate or freeze.

Earth- the third planet from the Sun in the solar system, the largest in diameter, mass and density among the inner planets. Scientific evidence indicates that the Earth was formed about 4.54 billion years ago, and soon acquired its own satellite - the Moon. It is believed that life on Earth appeared 3.5 billion years ago. Approximately 71% of the planet's surface is covered with water, the rest of the surface is occupied by continents and islands.

Outer planetsthe outer group planets located behind the asteroid belt are very different from the inner group planets. They have huge dimensions, low density, large masses, rotate faster, have a powerful atmosphere, gas-liquid shells and a small silicate core. The inner planets are also distinguished by a small number of satellites or their absence.

Weight Jupiter 314 times the mass of the Earth. Jupiter's magnetic field is 10 times stronger than the Earth's magnetic field, in addition, Jupiter is surrounded by powerful radiation belts. Jupiter has 4 rings and 16 moons

Saturn - the second largest planet, but has a very low density. Saturn is more of a gas planet. Saturn is known for its rings up to 400 thousand km in diameter.

Uranus is 4 times larger than the Earth and 14.5 times in mass. This is the third planet - a giant, rotating in the direction opposite to the rotation of most of the planets. Uranus is surrounded by a system of thin rings. Uranus has 26 satellites.

Neptune - the smallest of the giant planets, has the largest density among them. In the atmosphere of Neptune, as on Jupiter, large vortex structures are visible, changing in time. Neptune has a system of rings and 8 satellites on the surface of which there are traces of water-ice volcanism.

Pluto - the ninth planet from the Sun, very different from the giant planets. Pluto has a very elongated elliptical orbit that crosses Neptune's orbit as Pluto revolves around the Sun. It has a tenuous atmosphere surrounding the planet's icy surface. The large moon Charon (1172 km in diameter) consists of a mixture of ice and silicates and in its rotation around Pluto is always facing the planet with the same side.

11. The main natural uniqueness of the planet Earth

Earth is a unique planet! Like no other planet, ours is covered with green vegetation, a huge blue ocean containing more than a million islands, hundreds of thousands of streams and rivers, huge masses of land called continents, mountains, glaciers and deserts, which produce a wide variety of colors and textures.

Certain life forms can be found in virtually every ecological niche on the Earth's surface. Even in the very cold Antarctica, hardy microscopic creatures thrive in ponds, tiny wingless insects live in patches of mosses and lichens, and plants grow and bloom annually. From the top of the atmosphere to the bottom of the oceans, from the cold part of the poles to the warm part of the equator, life is flourishing. To this day, no signs of life have been found on any other planet.

Thus, our "normal" processes on Earth are undoubtedly unique among our solar system, and, according to what we know, throughout the universe:

1. She is an inhabited planet. It is the only planet in the solar system that supports life. All forms of life, from the smallest microscopic organisms to huge land and sea animals.

2. Its distance from the Sun (150 million kilometers) is advisable to give it an average temperature of 18 to 20 degrees Celsius. It is not as hot as Mercury and Venus, nor as cold as Jupiter or Pluto.

3. It has an abundance of water (71%), which is not found on any other planet. And which is not found on any of the planets known to us in a liquid state so close to the surface.

4. Has a biosphere that provides us with food, shelter, clothing and minerals.

5. Has no poisonous gases like helium or methane as Jupiter.

6. It is rich in oxygen, which makes life possible on Earth.

7. Its atmosphere acts as a blanket to protect the Earth from extreme temperatures.

Inner planets

the terrestrial planets closest to the Sun 4 large planets - Mercury, Venus, Earth, Mars - having a number of similar physical characteristics. See Planets.

Great Soviet Encyclopedia. - M .: Soviet encyclopedia. 1969-1978 .

See what "Inner planets" are in other dictionaries:

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The image of the solar system from the book by Andreas Cellarius Harmonia Macrocosmica (1708) The heliocentric system of the world the idea that the Sun is the central celestial body around which the Earth and others revolve ... Wikipedia

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