Characteristics of the land. General characteristics of the land

Earth– third planet solar system. Find out the planet's description, mass, orbit, size, interesting facts, distance to the Sun, composition, life on Earth.

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

Planet Earth also called the Blue Planet, Gaia, World and Terra, which reflects its role for each people in historical terms. We know that our planet is rich in many various forms life, but how exactly did she manage to become like this? First, consider some interesting facts about 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. Because of this, the length of the day increases. In 140 million years, a day will cover 25 hours.

Believed that the Earth was 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 is at the center of everything ( heliocentric system world), 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 rotates rapidly. The field is important because it protects us from the influence of the solar wind.

Has one satellite

• If you look at the percentage, the Moon protrudes largest satellite in the system. But in reality it is in 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 followed the tradition when discovering Uranus and Neptune.

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. Average earth density - 5.52 grams per cm 3.

Size, mass, orbit of planet Earth

With a radius of 6371 km and a mass of 5.97 x 10 24 kg, the Earth ranks 5th in size and massiveness. This is the largest planet earth type, but it is smaller in size than the gas and ice giants. However, in terms of density (5.514 g/cm3) it ranks first in the Solar System.

Polar compression	0,0033528
Equatorial	6378.1 km
Polar radius	6356.8 km
Average 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 falls at the equator	9.780327 m/s²
First escape velocity	7.91 km/s
Second escape 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.)

There is a slight eccentricity in the orbit (0.0167). The distance from the star at perihelion is 0.983 AU, and at aphelion – 1.015 AU.

One passage around the Sun takes 365.24 days. We know that due to existence leap year, we add a day every 4 passes. We are used to thinking that a day lasts 24 hours, but in reality this time takes 23 hours 56 minutes and 4 seconds.

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

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

Composition and surface of planet Earth

The shape of planet Earth is like a spheroid, flattened at the poles and with a convexity at the equatorial line (diameter - 43 km). This happens 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 crust. The first deepens to 2890 km (the densest layer). It is represented by silicate rocks with iron and magnesium. The crust is divided into lithosphere (tectonic plates) and asthenosphere (low viscosity). You can carefully examine the structure of the Earth in the diagram.

The lithosphere breaks down 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 notable for the fact that approximately 70.8% of its surface is covered with water. Bottom card The earth demonstrates tectonic plates.

The earth's landscape is different everywhere. The submerged surface resembles mountains and has 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. It also affects the transformation of glaciers, the creation of coral reefs, meteorite impacts, etc.

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

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

The outer layer contains soil. This is a certain 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 rise, the less air, pressure and density you will feel.

The troposphere is located closest to the surface (0-12 km). Contains 80% of the mass of the atmosphere, with 50% located within the first 5.6 km. It consists of nitrogen (78%) and oxygen (21%) with admixtures 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 line with relatively warm air. This is where it is located ozone layer. The temperature rises as the interlayer absorbs ultraviolet light. The atmospheric layers of the Earth are shown in the figure.

This is a stable layer and is practically free from turbulence, clouds and other weather formations.

At an altitude of 50-80 km there is the mesosphere. This is the coldest place (-85°C). It is located near the mesopause, extending from 80 km to the thermal pause (500-1000 km). The ionosphere lives within the range of 80-550 km. Here the temperature increases 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 auroras are formed and the International space station(320-380 km).

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

This mark is influenced by many factors. The Earth makes an axial revolution every 24 hours, which means one side always experiences night and lower temperatures. In addition, the axis is tilted, so the northern and southern hemispheres alternately move away and move closer.

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 was 70.7°C (Lut Desert), and the minimum of -89.2°C was reached at the Soviet Vostok station on the Antarctic plateau in July 1983.

Moon and asteroids of the Earth

The planet has only one satellite, which affects not only physical changes planet (for example, ebbs and flows), but also reflected in history and culture. To be precise, the Moon is the only celestial body on which a person has walked. This happened on July 20, 1969 and the right to take the first step went to Neil Armstrong. Overall, 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). We 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 gravitational locking (one side always faces the Earth).

The diameter covers 3474.8 km (1/4 of the Earth), and the mass is 7.3477 x 10 22 kg. The average density is 3.3464 g/cm3. In terms of gravity it reaches only 17% of the Earth's. The moon influences 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 falls into the Earth's shadow, and the second happens when a satellite passes between us and the Sun. The satellite's atmosphere is weak, causing temperatures 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 due to radioactive decay potassium There is also evidence of frozen water in craters. The surface is divided into various types. There is Maria - flat plains that ancient astronomers mistook for seas. Terras are lands, like highlands. You can even notice mountainous areas and craters.

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

Formation and evolution of planet Earth

In the 18th century, humanity came to the conclusion that our terrestrial planet, like the entire solar system, emerged from a nebulous 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 we know.

The primordial Earth appeared 4.54 billion years ago. From the very beginning, it was molten 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 arriving on comets formed the oceans.

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

The modern picture was created 40 million years ago and consolidated 2.58 million years ago. The last one is going on now ice age, which began 10,000 years ago.

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

Then 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 began during the Cambrian explosion.

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

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

Reasons for the habitability of planet Earth

If a 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. Besides, main star must provide sufficient light and heat to maintain the atmosphere. Important factor– location in the habitable zone (distance of the Earth from the Sun).

We should understand how lucky we are. After all, Venus is similar in size, but due to its close location to the Sun, it is a hellishly hot place with acid rain. And Mars, which lives 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.

There are also a lot of interesting things in the form. In ancient times the planet was considered flat, but different cultures added their own features. For example, in Mesopotamia, a flat disk floated in the middle of the ocean. The Mayans had 4 jaguars that held up the heavens. For the Chinese it was generally a cube.

Already in the 6th century BC. e. scientists sewed it onto 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 became established with the advent of the Roman Empire. About changes in earth's surface Aristotle also spoke. He believed that it happens too slowly, so a person is not able to catch it. 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 11th century Persia, explorers studied Indian geology. The theory of geomorphology was created by the Chinese naturalist Shen Guo. He identified marine fossils located far from the water.

In the 16th century, understanding and exploration of the Earth expanded. We should thank the heliocentric model of Copernicus, which proved that the Earth is not the universal center (previously used geocentric system). And also Galileo Galilei for his telescope.

In the 17th century, geology became firmly established among other sciences. They say that the term was coined by Ulysses Aldvandi or Mikkel Eschholt. The fossils discovered at that time caused serious controversy in the age of the earth. All the religious people insisted on 6000 years (as the Bible said).

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

The first geological maps of the Earth appeared in the 19th century. Main work– “Principles of Geology”, published in 1830 by Charles Lyell. In the 20th century, age calculations became much easier thanks to radiometric dating (2 billion years). However, the study of tectonic plates has already led to the 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 the plants will die, and in a billion years all living things will disappear, and the 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 view all earthly history, then humanity is just a fleeting flash. However, the Earth remains the most important planet, home and unique place. One can only hope that we will have time to populate other planets outside our system before critical period solar development. Below you can explore a map of the Earth's surface. In addition, our website contains many beautiful photos planets and places on Earth from space to high resolution. Using online telescopes from the ISS and satellites, you can observe the planet for free in real time.

Click on the image to enlarge it

Characteristics of the planet:

• Distance from the Sun: 149.6 million km
• Planet diameter: 12,765 km
• Day on the planet: 23h 56min 4s*
• Year on the planet: 365 days 6h 9min 10s*
• t° on the surface: global average +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)
**period of orbit 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 the planet that is of most interest is ours. common house, Earth. Ideas about it have 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 part of the group of terrestrial planets such as Mercury, Venus and Mars. 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 149.0 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 Earth is the only planet that has life! The Earth was positioned in an extremely fortunate way. It travels in orbit at a distance of almost 150,000,000 kilometers from the Sun, which means only one thing: It’s warm enough on Earth for water to remain liquid. Given 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.

The history of the origin of planet Earth

Starting from Theory Big Bang and based on the study of radioactive elements and their isotopes, scientists have found out the approximate age of the earth's crust - it 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 the gravitational compression of a cloud of interstellar dust, and after the star, 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. During the birth phase, obeying the laws of gravity, a large number of planetesimals and large cosmic bodies fell onto its ever-growing surface, which subsequently made up almost the entire modern mass of the earth. Under the influence of such bombardment, the planet's substance warmed up and then melted. Under the influence of gravity, heavy elements such as ferrum and nickel created the core, and lighter compounds formed the earth's mantle, crust with continents and oceans lying on its surface, and an atmosphere that was initially very different from the present one.

Internal structure of the Earth

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

Beneath the atmosphere of our planet there is a solid surface called 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 such movement, mountains and other features of the earth's surface appear.

The earth's crust has a thickness of 10 to 50 kilometers. 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 an outer liquid core, which extends further into the depths for another 2,260 kilometers. This layer is also movable and capable of producing 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

The 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. Water initially found in the atmosphere in the form of steam played a large role in the formation of the planet - 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 as a blue border around the planet. This thinnest dome consists of 77% nitrogen, 20% oxygen. The rest is a mixture of various gases. 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 of chance. It was the ocean that gave rise to the origin of life on the planet, and, as a consequence, the emergence of homo sapiens. Surprisingly, the oceans still hold many secrets. Developing, humanity continues to explore space. Entering low-Earth orbit has provided an opportunity to gain a new understanding of many of the geoclimatic processes occurring on Earth, the mysteries of which are still to be further studied by more than one generation of people.

Earth's satellite - Moon

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 wrote a map of the visible side of the lunar surface. In the 20th century, on February 3, 1966, the Luna-9 lander landed on the Moon for the first time, and a few years later, on July 21, 1969, a person set foot on the surface of the Moon for the first time.

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

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

Hello readers! It's a cool planet, isn't it? She is beautiful and loved. Today, in this article, I would like to tell you about what our planet is made of, what its shape, temperature, composition, size and a few other interesting things are...

Earth, on this planet we live, it is the fifth of major planets c and third from the Sun. On Earth, generally favorable , many natural resources, and it may be the only planet on which life exists.

Active geodynamic processes occurring in the bowels of the Earth are manifested in the growth of the oceanic crust and its further opening, earthquakes, eruptions, etc.

Shape and size.

The approximate contours and dimensions of the Earth have been known for more than 2000 years. The Greek scientist quite accurately calculated the radius of the Earth back in the 3rd century. BC e. In our time, it is already known that the polar radius of the Earth is about 12,711 km, and the equatorial radius is 12,754 km.

The Earth's surface area is about 510.2 million km2, of which 361 million km2 is water. The volume of the Earth is approximately 1121 billion km 3. Due to the rotation of the planet, a centrifugal force arises, which is maximum at the equator and decreases towards the poles; this rotation is responsible for the uneven radii of the Earth.

If only this one force acted on Earth, then all objects located on the surface would fly into space, but thanks to the force of gravity, this does not happen.

Gravity.

Gravity, or the force of the earth's attraction, keeps the atmosphere near the earth's surface and the moon in orbit. With height, the force of gravity decreases. The state of weightlessness that astronauts feel is explained precisely by this circumstance.

Due to the rotation of the Earth and the action of centrifugal force, gravity on its surface decreases somewhat. The acceleration of freely falling objects, the value of which is 9.8 m/s, is due to the force of gravity.

The heterogeneity of the Earth's surface leads to differences in gravity in different areas. Information about internal structure The Earth allows you to obtain a measurement of the acceleration of the force of weight.

Mass and density.

The mass of the Earth is approximately 5976 ∙ 10 21 tons. For comparison, the mass of the Sun is approximately 333 thousand times greater, and the mass of Jupiter is 318 times greater. But on the other hand, the mass of the Earth exceeds the mass of the Moon by 81.8 times. The Earth's density varies from extremely high in the center of the planet to negligible in upper layers atmosphere.

Knowing the mass and volume of the Earth, scientists calculated that its average density is approximately 5.5 times greater than the density of water. Granite is one of the most common fossils on the Earth's surface, its density is 2.7 g/cm3, the density in the mantle varies from 3 to 5 g/cm3, within the core - from 8 to 15 g/cm3. At the center of the Earth it can reach 17 g/cm3.

Conversely, the density of air near the Earth's surface is approximately 1/800th the density of water, and in the upper atmosphere it is very small.

Pressure.

At sea level, the atmosphere exerts a pressure of 1 kg/cm2 (pressure of one atmosphere), and with height it decreases. The pressure decreases by approximately 2/3 at an altitude of about 8 km. Inside the Earth, the pressure increases rapidly: at the boundary of the core it is about 1.5 million atmospheres, and in its center - up to 3.7 million atmospheres.

Temperatures.

On Earth, temperatures vary greatly. For example, in Al-Azizia (Libya), a record high temperature 58 °C (September 13, 1922), and at the Vostok station near South Pole Antarctica, record low – 89.2 °C (July 21, 1983).

In depth, the temperature rises by 0.6 °C every 18 m, then this process slows down. The earth's core, located in the center of the Earth, is heated to a temperature of 5000 - 6000 °C.

The average air temperature in the near-surface sphere of the atmosphere is 15 °C, it decreases gradually in the troposphere, and above (starting from the stratosphere) it varies within wide limits depending on the absolute altitude.

The cryosphere is the shell of the Earth, usually the temperature within which is below 0 °C. At high latitudes it begins at sea level, and in the tropics at an altitude of about 4500 m. The cryosphere in subpolar regions on continents can extend several tens of kilometers below the earth's surface, forming the horizon.

Thus, I told you the most important facts about the Earth, as it were, from the inside. From the side from which we usually never thought. It was brief description Earth. I hope this article was the answer to your search. 🙂

Earth is a unique planet! Of course, this is true in our solar system and beyond. Nothing that scientists have observed leads to the idea that there are other planets like Earth.

Earth is the only planet orbiting our sun on which we know life exists.

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

Some forms of life can be found in almost every ecological niche on the surface of the Earth. Even in the very cold of Antarctica, hardy microscopic creatures thrive in ponds, tiny wingless insects live in patches of moss and lichen, 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 flourishes. To this day, no signs of life have been found on any other planet.

The Earth is enormous in size, about 13,000 km in diameter, and weighing approximately 5.98 1024 kg. The Earth is on average 150 million km from the Sun. If the Earth goes much faster on its 584 million kilometer journey around the Sun, its orbit will become larger and it will move further away from the Sun. If it is too far from the narrow habitable zone, all life will cease to exist on Earth.

If this ride gets any slower in its orbit, the Earth will move closer to the Sun, and if it moves too close, all life will die as well. The Earth travels around the Sun in 365 days, 6 hours, 49 minutes and 9.54 seconds (a sidereal year), equivalent to more than a thousandth of a second!

If average annual temperature Earth's surface will change by just a few degrees or so, most of the life on it will eventually become fried or frozen. This change will disrupt water-glacier relations and other important balances, with catastrophic results. If the Earth rotates slower than its axis, all life will die in time, either by freezing at night from lack of heat from the Sun or by burning during the day from too much heat. large quantity heat.

Thus, our "normal" processes on Earth are undoubtedly unique among our Solar System, and, according to what we know, in the entire Universe:

1. It is a habitable planet. It is the only planet in the solar system that supports life. All forms of life right 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 average temperature from 18 to 20 degrees Celsius. It's not as hot as Mercury and Venus, nor as cold as Jupiter or Pluto.

3. It has an abundance of water (71%) that 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. Does not have poisonous gases like helium or methane as Jupiter.

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

7. Its atmosphere acts as a blanket of protection for the Earth from extreme temperatures.

Page 1 of 1 1

The place of planet Earth in the hierarchical organization of the Universe: Universe  Metagalaxy  our Galaxy (Milky Way galaxy)  Solar system  Earth.

Our Galaxy unites more than 150 billion stars and more than 100 million nebulae. It has a spiral shape, symmetrical relative to the main galactic plane, the diameter of which is about 30,000 parsecs (1 n = 3.26 light years).

The solar system is located at a distance of about 10,000 parsecs from the center of the Galaxy (2/3 of the radius of the Galaxy), 25 n north of the galactic plane. The closest star to the Sun, Proxima Centauri, is located at a distance of 1.31 n. The Sun, an average-sized star in the Galaxy, moves, like other Stars, around its center, making a full revolution in approximately 230 million years (galactic year). The dimensions of the Solar system compared to the distances between the stars are very small (5905 million km to the orbit of Pluto from the Sun) (Fig. 1).

Position of the Earth in space and its physical properties

Earth, the third planet from the Sun, is one of the nine planets in the solar system. The Earth, like the other planets, revolves around the Sun in an elliptical orbit. At the same time, it rotates around its own axis, which is constantly tilted relative to the orbital plane by 66.5.

The main physical properties of the Earth are shape, size, mass, density, pressure and temperature.

Shape and dimensions. The shape of the Earth is a ball, flattened at the poles (spheroid of revolution). The length of the equatorial radius of this ball is 6378 km, the vertical radius is 6357 km, and the circumference of the Earth along the equator is 40076 km. The true geometric shape of the Earth has been named geoid. The area of ​​the Earth is 510.2 million km2.

Weight Earth is 5.98  1024 kg.

Density surface layers globe equal to 2.7-3.0 g/cm2. Density increases with depth and in the center of the Earth approaches 11.3 g/cm2. The average density of the Earth is 5.52 g/cm2.

Pressure increases with increasing density and increases by 27.5 MPa with each kilometer. At the center of the Earth it is 300 thousand MPa.

Temperature different in the surface and deep layers. The temperature of the Earth's surface is determined by the influx of energy from the Sun and depends on the geographic latitude of the area and the time of year. The upper part of the earth's crust warms up to an insignificant depth, below which there is a zone of constant temperature equal to the average annual temperature of the area. Below this zone the temperature rises. The vertical distance at which the temperature increases by 1°C is called geothermal stage. Its average value is 33 m. At great depths, the geothermal step is not observed. The temperature of the center of the Earth is 2000-3000°C.

The earth creates a row geophysical fields : gravitational, magnetic, electrical and thermal.

The emergence and existence of the geographical envelope and life on Earth are determined by the shape and size of our planet, as well as its distance from the Sun.

71% of the Earth's surface is occupied by the oceans and only 29% by land. Land is distributed unevenly among the World Ocean. In the northern hemisphere it occupies 39% of the total area, and in the southern hemisphere - 19%. IN southern hemisphere, unlike the north, in temperate latitudes (50-60) there is almost no land, but in the polar region there is a continent - Antarctica. There are a huge number of islands in the Ocean, 18 of which have an area of ​​more than 100 thousand km 2. The largest island, Greenland (2176 km 2), is 4.5 times smaller than the smallest continent, Australia.

Earth movements

The Earth revolves around the Sun in an elliptical orbit. At the same time, it rotates around its own axis.

Rotation of the Earth around its axis

The earth rotates around an axis from west to east. The main physical proof of this is the experiment with Foucault's swinging pendulum.

The rotation of the Earth around its axis has certain geographical consequences:

Compression of the Earth at the poles. Previously, when the Earth rotated at a higher speed, the polar compression was greater.

Deflection of bodies moving horizontally(winds, sea currents, etc.) from their initial movement (Coriolis acceleration). In the northern hemisphere, bodies deviate to the right, in the southern hemisphere - to the left.

Change of day and night. This phenomenon underlies daily periodicity in live and inanimate nature. The daily rhythm is determined by changes in light and temperature conditions.

Rotation of the Earth around the Sun

The Earth's path around the Sun is called an orbit. The Earth's orbit has the shape of an ellipse, with the Sun at one of its focuses. Therefore, the distance from the Earth to the Sun varies throughout the year from 147 million km - at perihelion (in January) to 152 million km - at aphelion (in July). The Earth moves in orbit from west to east at an average speed of about 30 km/s and travels the entire path in a year - 365 days 6 hours 9 minutes 9 seconds.

The Earth's rotation axis is inclined to the orbital plane at an angle of 66.50 and moves in space parallel to itself throughout the year. This leads to the most important geographical consequences - the change of seasons and the inequality of day and night.

The inclination of the earth's axis to the orbital plane and the preservation of its orientation in space causes different angles of incidence of solar rays and, accordingly, differences in the flow of heat to the earth's surface, as well as unequal lengths of day and night throughout the year at all latitudes except the equator.

Summer Solstice Day (June 22). On this day, the northern end of the earth's axis faces the Sun, sun rays at noon they fall vertically to 23.5° parallel north latitude - northern tropic . All parallels north of the equator up to 66.5°N. Most of the day is illuminated; at these latitudes, the day is longer than the night. North of 66.5° N latitude. On the day of the summer solstice, the territory is completely illuminated by the Sun - it is a polar day there. Parallel 66.5° N is the boundary from which it begins polar day- This Arctic Circle . On the same day, at all parallels south of the equator to 66.5° S. the day is shorter than the night. South of 66.5° S. The area is not illuminated at all - there polar night. Parallel 66.5° S - Antarctic Circle . June 22 is the beginning of astronomical summer in the northern hemisphere and astronomical winter in the southern hemisphere.

Winter Solstice Day (December 22). On this day, the earth's axis with its southern end faces the Sun, the sun's rays at noon fall vertically at 23.5° parallel to southern latitude - southern tropic . On all parallels south of the equator up to 66.5° S. the day is longer than the night. Starting from the southern polar circle it is established polar day. On this day, at all parallels north of the equator up to 66.5° N latitude. the day is shorter than the night. Beyond the Arctic Circle - polar night. December 22 is the beginning of astronomical summer in the southern hemisphere, astronomical winter in the northern hemisphere.

The vernal equinox (March 21) and the autumn equinox (September 23). These days the terminator passes through both poles of the Earth and divides all parallels in half. The northern and southern hemispheres are equally illuminated these days, daylight everywhere on Earth equal to night. The sun's rays at noon are at their zenith above the equator, the hemispheres receive the same amount of heat. On Earth, March 21 and September 23 are the beginning of astronomical spring and autumn in the respective hemispheres.

The change of seasons is at the core seasonal periodism in living and inanimate nature. The seasonal rhythm is determined by changes in temperature, air humidity, duration of illumination during the day, etc.

The earth has five lighting belts . They are limited from each other by the tropics and polar circles. The lighting belts differ in the height of the sun's midday position above the horizon, the length of the day and, accordingly, the amount of heat entering the earth's surface.

Hot belt limited to the northern and southern tropics. Within its boundaries, the Sun is at its zenith twice a year, in the tropics - once a year, on the days of the solstices (and in this they differ from all other parallels). At the equator, day is always equal to night; at other latitudes of this zone, their duration differs little. Hot belt occupies about 40% of the earth's surface.

Temperate zones (there are two of them) are located: one between the northern tropic and the Arctic Circle, the other between the southern tropic and the southern Arctic Circle. The sun is never at its zenith in them. During the day there is always a change of day and night, and their duration depends on the latitude and time of year. Near the polar circles (from 60 to 66.5°) in the summer there are bright, so-called white nights with twilight illumination due to the merging of the evening and morning dawn, since the Sun briefly and shallowly goes below the horizon. The total area of ​​temperate zones is 52% of the earth's surface.

Cold belts (there are also two of them) are located: one north of the Arctic Circle, the other south of the Antarctic Circle. They are distinguished by the presence of polar days and nights, the duration of which increases from one day - at the polar circles (and this is how they differ from all other parallels) to six months - at the poles. Their total area 8% of the earth's surface.

Lighting belts are the basis of climatic zonation and natural zonation in general.