Surely every person has wondered: how is our planet different from all the others, except that it is inhabited by living organisms? Even at school, we were told that the Earth is very different from the eight planets of the solar system (after all, today we do not classify Pluto as a full-fledged planet). Of course, few people remember school lessons astronomy, so in this article we will identify the main differences.

Definition

Earth is the only planet in the solar system that has life. It is often called the Blue Planet (due to the fact that there is a huge amount of water on Earth). As scientists say, our planet was formed approximately 4.5 billion years ago, and soon it acquired a natural satellite - the Moon. Thanks to numerous studies, it was found that life on our planet did not form immediately, but only a billion years after its creation. Life on Earth is possible, among other things, due to the influence magnetic field, which significantly weakens the radiation of the Sun, which is destructive for all living organisms on the planet. Just over 70 percent of the surface is occupied by the oceans, while land accounts for less than thirty percent.

Other planets of the solar system Most of them remain a mystery to us, many of which we have yet to uncover. The main question that torments scientists is whether there is life on other planets? To date, the answer is no, but some scientists still suggest that this opinion may be wrong. The planets can be divided into two groups: the planets of the Terrestrial group (in addition to the Earth itself, these are Mars, Venus and Mercury), as well as the giant planets (these are Jupiter, Saturn, Uranus and Neptune). Each of these objects is of great interest to us, especially the most major planets– Jupiter and Saturn. For example, the famous rings of Saturn are constantly studied by various specialists, and the results obtained often cause a wide resonance in the public.

Comparison

Of course, the presence of intelligent life greatly distinguishes the Earth from other planets. However, there are other signs of difference. We will highlight five main ones:

• Our planet has a liquid shell. None of the planets or their satellites can boast of this. As noted above, a larger percentage of the planet’s surface is water.
• Despite the fact that the atmosphere can be found not only on Earth, our planet is the only one that contains such a huge amount of oxygen.
• Another difference is the presence of a unique satellite. The fact is that the Moon is enormous in size if you compare the satellite directly with the planet. No one else has such a ratio, including the planets of the Earth group.
• Planet Earth is also very different in appearance when observed from Space. Particularly clearly visible are parts of the World Ocean - such blue color no planet has.
• The Earth has unique physical properties, which are suitable for the existence of a protein form of life.

Conclusions website

1. Intelligent life forms are present only on Earth.
2. Only on Earth there is water (liquid shell).
3. Our planet has a huge amount of oxygen.
4. There is a unique satellite - the Moon, which largely determines living conditions.
5. Differences can also be found in appearance(blue color of planet Earth).
6. The earth has unique physical properties that are conducive to the development of protein life forms.

What regions are distinguished in the solar system?

What are the features of the Solar System?

Give the main characteristics of the Solar System.

Describe the structure of the Sun.

What are the theories of the origin of the solar system?

What is the generally accepted hypothesis for the origin of the solar system?

Define a planet.

What are the main attributes and parameters of the planet?

What are the general characteristics of the terrestrial planets?

Give the characteristics of Mercury.

Describe Venus.

Describe the Earth's satellite.

Give characteristics of Mars.

Describe the moons of Mars.

Describe the planets small group– asteroids.

Describe the dwarf planet Ceres.

How do meteorites form and how are they characterized?

Give general characteristics giant planets compared to planets terrestrial group.

Give characteristics of Jupiter.

Describe the main moons of Jupiter.

Give characteristics of Saturn.

Describe the main moons of Saturn.

Give characteristics of Uranus.

Describe the main moons of Uranus.

Describe Neptune.

Describe Neptune's main moons.

What are comets?

What are centaurs?

What about trans-Neptunian objects?

Describe the Kuiper Belt.

Which planets are classified as dwarfs?

Describe Pluto.

Describe the dwarf planets: Haumea, Makemake, Eris.

What is special about a scattered disk?

What is special about the distant regions of the solar system?

What is special about the border regions of the solar system?

Chapter 5 Geological Evolution

5.1. Earth is like a planet

Its differences from other terrestrial planets

Earth is the third planet from the Sun. The average distance from the Sun of 149.6 million km is taken as 1 astronomical unit. The average orbital speed is 29.765 km/s. The period of revolution around the Sun is 365.24 days. The inclination of the earth's axis to the ecliptic plane is 66 0. The period of rotation around the axis is 23 hours 56 minutes. The shape of the earth is geoid. Due to rotation, its shape is close to an ellipsoid, flattened at the poles and stretched in the equatorial zone. The average radius of the Earth is 6371.032 km. The Earth has a magnetic field that is dipole in nature. Magnetic poles do not coincide with geographic ones.

The available information allows for a comparative study of the outer shells of the Earth and other planets of the Solar System. On this basis, a new scientific direction arose, called comparative planetology. Other planets are surprisingly unlike Earth, although they are subject to the same physical laws.

Earth is the largest planet in its group. But, as estimates show, even such dimensions and mass are minimal for retaining their gas atmosphere. The Earth is rapidly losing hydrogen and some other light gases, which is confirmed by observations of its so-called plume.

The Earth's atmosphere is fundamentally different from the atmospheres of other planets: it has a low content of carbon dioxide, a high content of molecular oxygen and a relatively large amount of water vapor. Two reasons create the isolation of the Earth’s atmosphere: the water of the oceans and seas absorbs carbon dioxide well, and the biosphere saturates the atmosphere with molecular oxygen formed during the process of plant photosynthesis. Calculations show that if we release all the carbon dioxide absorbed and bound in the oceans, simultaneously removing from the atmosphere all the oxygen accumulated as a result of the life of plants, then the composition of the earth’s atmosphere in its main features would become similar to the composition of the atmospheres of Venus and Mars.

In the Earth's atmosphere, saturated water vapor creates a cloud layer covering a significant part of the planet. Clouds are an important element in the water cycle that occurs on our planet in the hydrosphere - atmosphere - land system.

The planets closest to the Sun - Mercury and Venus - rotate very slowly around their axis, with a period of tens to hundreds of Earth days. The slow rotation of these planets appears to be due to their resonant interactions with the Sun and each other. The Earth and Mars rotate with almost identical periods - about 24 hours.

Only the Earth in its group has a strong magnetic field of its own, which is more than two orders of magnitude greater than the magnetic fields of other planets.

None of the terrestrial planets has a developed system of satellites, which is typical for giant planets. The planet-like satellite of the Earth, the Moon, is close in size to Mercury. There is still no clear idea about the origin of the Moon.

The relief of the earth's surface as a whole is characterized by a global asymmetry of two hemispheres (northern and southern): one of them is a gigantic space filled with water. These are oceans, occupying more than 70% of the entire surface. In the other hemisphere, the crustal uplifts that form the continents are concentrated. Oceanic and continental varieties of crust differ both in age and in chemical and geological composition. It is clear that the topography of the ocean floor is different from the continental topography. Systematic studies of the sea and ocean floor became possible only in Lately. They have already led to a new understanding of the global nature of tectonic processes occurring on Earth. The average depth of the world's oceans is close to 4 km, individual depressions reach 10 km or more, and individual cones rise significantly above the surface of the water. The main attraction of the oceanic relief is the global system of median ridges, stretching for tens of thousands of kilometers (72 thousand km). The chains of mountain ranges entwine Earth. The Alps, Caucasus, Pamirs, Himalayas, even taken together, are incomparable with the discovered strip of the middle ridges of the World Ocean. Along them central parts there are faults, the so-called rift zones, through which fresh masses of matter emerge from the mantle to the surface. They push apart the oceanic crust, shaping it through a process of continuous renewal. The age of the oceanic crust does not exceed 150 million years. Another characteristic feature of the process is the existence subduction zones, where the oceanic crust plunges under one of the island arcs (for example, under the Kuril, Mariana, etc.) or under the edge of the continent. These zones are characterized by increased seismic and volcanic activity. Thus, only on earth there is a powerful hydrosphere that was formed simultaneously with the planet.

The relief of the continental part of the planet is more diverse: plains, hills, plateaus, mountain ranges and huge mountain systems. Certain areas of land lie below ocean level (for example, the Dead Sea area), and some mountain ranges are raised above its level by 8-9 km. According to modern views, the continental crust, together with the underlying layers of the mantle, forms a system of lithospheric continental plates. Unlike the lithosphere of the oceans, continental plates have a very ancient origin, their age is estimated at 2.5-3.8 billion years. The thickness of the central part of some of them reaches 250 km.

At the boundaries of lithospheric plates, called geosynclines, either compression or stretching of the crust occurs, which depends on the direction of the local horizontal displacement of the plates.

In the modern era, only the Earth remains a “living” planet, the geological development of which continues and manifests itself, in particular, in active tectonic activity. Mars and Venus went through periods of intense seismic and volcanic activity in the past, but this ceased on Mars several hundred million years ago and on Venus more than a billion years ago. Both of these planets are most likely completing or have already completed the cycle of their evolutionary development.

Numerous signs indicate that processes in the bowels of the Earth have proceeded and continue to proceed differently from those of Venus and Mars. This is indicated by such facts as the existence of a continental crust with granite rocks, clearly defined lithospheric plates with their movements under the influence of deep processes, and the presence of a relatively powerful magnetic field near the Earth.

Advances in science and technology have made direct study of the planets of the solar system accessible, opening up fundamentally new opportunities for comparative knowledge of our own planet. Thus, a new page has been opened in understanding the world around us, but so far only the first lines have been written on it. A particularly exciting question still remains unresolved: what distinguished the Earth from the families of planets of the same type so that it could become an abode of life? The question remains open about the possible existence of some forms of life on Mars in the distant past.

Methods for studying the structure of the Earth

Most of the special sciences about the Earth are the sciences about its surface, including the atmosphere. Until man penetrated deeper into the Earth further than 12-15 km (Kola superdeep well). From depths of approximately 200 km, subsurface matter is carried out in different ways and becomes available for research. Information about deeper layers is obtained by indirect methods: by recording the nature of the passage of seismic waves different types through the earth's interior, by studying meteorites as relict remains of the past, reflecting the composition and structure of the matter of the protoplanetary cloud in the zone of formation of the terrestrial planets. On this basis, conclusions are drawn about the coincidence of the substance of meteorites of a certain type with the substance of certain layers of the earth's depths. Conclusions about the composition of the earth's interior, based on data on the chemical and mineralogical composition of meteorites falling on the earth, are not considered reliable, since there is no generally accepted model of the formation and development of the Solar system.

Structure of the Earth

Probing of the earth's interior with seismic waves made it possible to establish their shell structure and differentiated chemical composition.

There are 3 main concentrically located regions: core, mantle, crust. The core and mantle, in turn, are divided into additional shells that differ in physical and chemical properties (Fig. 50).

The core occupies the central region of the earth's geoid and is divided into 2 parts. Inner core is in a solid state, it is surrounded outer core staying in the liquid phase. There is no clear boundary between the inner and outer cores; they are distinguished by transition zone. The composition of the core is believed to be identical to that of iron meteorites. The inner core consists of iron (80%) and nickel (20%). The corresponding alloy at the pressure of the earth's interior has a melting point of the order of 4500 0 C. The outer core contains iron (52%) and eutectic (liquid mixture of solids) formed by iron and sulfur (48%). A small admixture of nickel cannot be ruled out. The melting point of such a mixture is estimated at 3200 0 C. In order for the inner core to remain solid and the outer core liquid, the temperature in the center of the Earth should not exceed 4500 0 C, but also not be lower than 3200 0 C. Ideas about the nature of terrestrial magnetism are associated with the liquid state of the outer core .

Rice. 50. Structure of the Earth

Paleomagnetic studies of the nature of the planet’s magnetic field in the distant past, based on measurements of the remanent magnetization of earth rocks, showed that over 80 million years there was not only the presence of magnetic field strength, but also multiple systematic magnetization reversals, as a result of which the north and south magnetic poles of the Earth swapped places. During periods of polarity change, moments of complete disappearance of the magnetic field occurred. Consequently, terrestrial magnetism cannot be created by a permanent magnet due to the stationary magnetization of the core or some part of it. It is believed that the magnetic field is created by a process called the self-excited dynamo effect. The role of the rotor (moving element) of the dynamo can be played by the mass of the liquid core, moving as the Earth rotates around its axis, and the excitation system is formed by currents that create closed loops inside the sphere of the core.

The density and chemical composition of the mantle, according to seismic waves, differ sharply from the corresponding characteristics of the core. The mantle is formed by various silicates (compounds based on silicon). It is assumed that the composition of the lower mantle is similar to that of stony meteorites (chondrites).

The upper mantle is directly connected to the outermost layer - the crust. It is considered a “kitchen” where many of the rocks that make up the bark or their semi-finished products are prepared. The upper mantle is believed to consist of olivine (60%), pyroxene (30%) and feldspar (10%). In certain zones of this layer, partial melting of minerals occurs and alkaline basalts are formed - the basis of the oceanic crust. Through rift faults of the mid-ocean ridges, basalts come from the mantle to the Earth's surface. But the interaction between the crust and the mantle is not limited to this. The fragile crust, which has a high degree of rigidity, together with part of the underlying mantle, forms a special layer about 100 km thick, called lithosphere. This layer rests on the upper mantle, whose density is noticeably higher. The upper mantle has a feature that determines the nature of its interaction with the lithosphere: in relation to short-term loads it behaves as a rigid material, and in relation to long-term loads - as a plastic one. The lithosphere creates a constant load on the upper mantle and, under its pressure, the underlying layer, called asthenosphere, exhibits plastic properties. The lithosphere “floats” in it. This effect is called isostasy.

The asthenosphere, in turn, rests on the deeper layers of the mantle, the density and viscosity of which increase with depth. The reason for this is the compression of rocks, causing a structural restructuring of some chemical compounds. For example, crystalline silicon in its normal state has a density of 2.53 g/cm 3 , under the influence of increased pressures and temperatures it transforms into one of its modifications, called stishovite, the density of which reaches 4.25 g/cm 3 . Silicates composed of this modification of silicon have a very compact structure. In general, the lithosphere, asthenosphere and the rest of the mantle can be considered as a three-layer system, each part of which is mobile relative to the other components. The light lithosphere, resting on a not too viscous and plastic asthenosphere, is particularly mobile.

The Earth's crust, which forms the upper part of the lithosphere, is mainly composed of eight chemical elements: oxygen, silicon, aluminum, iron, calcium, magnesium, sodium and potassium. Half of the total mass of the bark is oxygen, which is contained in it in bound states, mainly in the form of metal oxides. The geological features of the crust are determined by the combined effects of the atmosphere, hydrosphere and biosphere on it - these three outer shells of the planet. The composition of the bark and outer shells is continuously renewed. Thanks to weathering and demolition, the material of the continental surface is completely renewed in 80-100 million years. The loss of continental substances is compensated by secular uplifts of their crust. The vital activity of bacteria, plants and animals is accompanied by a complete change of carbon dioxide contained in the atmosphere in 6-7 years, oxygen - in 4,000 years. The entire mass of the hydrosphere (1.4 · 10 18 t) is completely renewed in 10 million years. An even more fundamental circulation of matter on the surface of the planet occurs in processes that connect all the internal shells into a single system.

There are stationary vertical flows called mantle jets; they rise from the lower mantle to the upper mantle and deliver flammable material there. Phenomena of the same nature include intraplate “hot fields”, which, in particular, are associated with the largest anomalies in the shape of the Earth’s geoid. Thus, the way of life in the interior of the earth is extremely complex. Deviations from mobilist positions do not undermine the idea of ​​tectonic plates and their horizontal movements. But it is possible that in the near future a more general theory of the planet will appear, taking into account horizontal plate movements and open vertical transfers of combustible matter in the mantle.

The uppermost shells of the Earth - the hydrosphere and atmosphere - are noticeably different from the other shells that form the solid body of the planet. By mass, this is a very small part of the globe, no more than 0.025% of its total mass. But the significance of these shells in the life of the planet is enormous. The hydrosphere and atmosphere arose at an early stage of the formation of the planet, and perhaps simultaneously with its formation. There is no doubt that the ocean and atmosphere existed 3.8 billion years ago.

The formation of the earth followed a single process that caused the chemical differentiation of the interior and the emergence of the precursors of the modern atmosphere and hydrosphere. First, the Earth's proto-core formed from grains of heavy non-volatile substances, then it very quickly attached the substance that later became the mantle. And when the Earth reached approximately the size of Mars, the period of its bombardment began planetesimalia. The impacts were accompanied by strong local heating and melting of the earth's rocks and planetesimalia. At the same time, gases and water vapor contained in the rocks were released. And since the average surface temperature of the planet remained low, water vapor condensed, forming a growing hydrosphere. In these collisions, the Earth lost hydrogen and helium, but retained heavier gases. The content of isotopes of noble gases in the modern atmosphere allows us to judge the source that generated them. This isotopic composition is consistent with the hypothesis about the impact origin of gases and water, but contradicts the hypothesis about the process of gradual degassing of the earth's interior as a source of formation of the atmosphere and hydrosphere. The ocean and atmosphere certainly existed not only throughout the history of the Earth as a formed planet, but also during the main accretion phase, when the proto-Earth was the size of Mars.

The idea of ​​impact degassing, considered as the main mechanism for the formation of the hydrosphere and atmosphere, is gaining increasing recognition. Laboratory experiments confirmed the ability of impact processes to release noticeable amounts of gases, including molecular oxygen, from earth rocks. This means that some amount of oxygen was present in the earth’s atmosphere even before the biosphere arose on it. Ideas about the abiogenic origin of some of the atmospheric oxygen were also put forward by other scientists.

Both outer shells - the atmosphere and the hydrosphere - interact tightly with each other and with the rest of the Earth's shells, especially with the lithosphere. They are directly influenced by the Sun and Space. Each of these shells is an open system, endowed with a certain autonomy and its own internal laws of development. Everyone who studies the oceans of air and water is convinced that the objects of study display an amazing subtlety of organization and the ability to self-regulate. But at the same time, none of the earth’s systems falls out of the general ensemble, and their joint existence demonstrates not just the sum of its parts, but a new quality.

Among the community of the Earth's shells, the biosphere occupies a special place. It covers the upper layer of the lithosphere, almost the entire hydrosphere and lower layers of the atmosphere. The term “biosphere” was introduced into science in 1875 by the Austrian geologist E. Suess (1831-1914). The biosphere was understood as the totality of living matter inhabiting the surface of the planet along with its habitat. A new meaning was given to this concept by V.I. Vernadsky, who considered the biosphere as a systemic formation. The significance of this system goes beyond the purely earthly world, which represents a link on a cosmic scale.

Age of the Earth

In 1896, the phenomenon of radioactivity was discovered, which led to the development of radiometric dating methods. Its essence is as follows. The atoms of some elements (uranium, radium, thorium, etc.) do not remain constant. The original, called mother element, spontaneously disintegrates, turning into a stable daughter. For example, uranium-238, when decaying, turns into lead-206, and potassium-40 into argon-40. By measuring the number of parent and daughter elements in a mineral, it is possible to calculate the time that has passed since its formation: the higher the percentage of daughter elements, the older the mineral.

According to radiometric dating, the oldest minerals on Earth are 3.96 billion years old, and the oldest single crystals are 4.3 billion years old. Scientists believe that the Earth itself is older, because radiometric counting is carried out from the moment of crystallization of minerals, and the planet existed in a molten state. These data, coupled with the results of studies of lead isotopes in meteorites, lead to the conclusion that the entire solar system was formed approximately 4.55 billion years ago.

Origin of continents.

Evolution earth's crust: plate tectonics

In 1915, the German geophysicist A. Wegener (1880-1930) suggested, based on the outlines of the continents, that during the geological period there was a single land mass, which he called Pangea(Greek: “all the earth”). Pangea split into Laurasia and Gondwana. 135 million years ago Africa separated from South America, and 85 million years ago North America - from Europe; 40 million years ago, the Indian continent collided with Asia and Tibet and the Himalayas appeared.

The decisive argument in favor of the adoption of this concept was the empirical discovery in the 50s of the 20th century of the expansion of the ocean floor, which served Starting point creation of lithospheric plate tectonics. It is currently believed that the continents are moving apart under the influence of deep convective currents directed upward and to the sides and pulling the plates on which the continents float. This theory is also confirmed by biological data on the distribution of animals on our planet. The theory of continental drift, based on plate tectonics, is now generally accepted in geology.

Also supporting this theory is that the coastline of eastern South America strikingly coincides with the coastline of western Africa, and the coastline of eastern North America– with the coastline of western Europe.

One of the modern theories explaining the dynamics of processes in the earth's crust is called theory of neomobilism. Its origins date back to the late 60s of the 20th century. and was caused by the sensational discovery at the bottom of the ocean of a chain of mountain ranges entwining the globe. There is nothing like it on land. The Alps, Caucasus, Pamirs, Himalayas, even taken together, are incomparable with the discovered strip of the middle ridges of the World Ocean. Its length exceeds 72 thousand km.

Humanity seemed to have discovered a previously unknown planet. The presence of narrow depressions and large basins, deep gorges stretching almost continuously along the axis of the median ridges, thousands of mountains, underwater earthquakes, active volcanoes, strong magnetic, gravitational and thermal anomalies, hot deep-sea springs, colossal accumulations of ferromanganese nodules - all this was discovered in a short period time at the bottom of the ocean.

As it turned out, the oceanic crust is characterized by constant renewal. It originates at the bottom of the rift, cutting the median ridges along the axis. The ridges themselves are from the same font and are also young. Oceanic crust“dies” in places of splits - where it moves under neighboring plates. Sinking deep into the planet, into the mantle and melting, it manages to give up part of itself, along with the sediments accumulated on it, for the construction of the continental crust. The density stratification of the Earth's interior gives rise to a kind of flow in the mantle. These currents provide material for the growth of the ocean floor. They also cause global plates with continents protruding from the World Ocean to drift. The drift of large plates of the lithosphere with land rising on them is called neomobilism.

The movement of continents has now been confirmed by observations from spacecraft. Researchers saw the birth of the ocean crust with their own eyes, approaching the bottom of the Atlantic, Pacific and Indian oceans, and the Red Sea. Using modern deep-sea diving techniques, aquanauts discovered the formation of cracks in the stretched bottom and young volcanoes rising from such “cracks.”

Earth is like a planet. Its difference from other planets
Earth? (lat. Terra) is the third planet from the Sun in the Solar System, the largest in diameter, mass and density among the terrestrial planets.
Most often referred to as Earth, planet Earth, World. The only body currently known to man, the Solar System in particular and the Universe in general, inhabited by living beings.
Scientific evidence indicates that the Earth formed from the Solar Nebula about 4.54 billion years ago, and shortly thereafter acquired its only natural satellite, the Moon. Life appeared on Earth about 3.5 billion years ago. Since then, the Earth's biosphere has significantly changed the atmosphere and other abiotic factors, causing the quantitative growth of aerobic organisms, as well as the formation of the ozone layer, which, together with the Earth's magnetic field, weakens harmful solar radiation, thereby maintaining conditions for life on Earth. The Earth's crust is divided into several segments, or tectonic plates, that gradually migrate across the surface over periods of many millions of years. Approximately 70.8% of the planet's surface is occupied by the World Ocean, the rest of the surface is occupied by continents and islands. Liquid water, essential for all known life forms, does not exist on the surface of any known planets or planetoids in the Solar System. The Earth's interior is quite active and consists of a thick, relatively solid layer called the mantle, which covers a liquid outer core (which is the source of the Earth's magnetic field) and an inner solid iron core.
The Earth interacts (is pulled by gravitational forces) with other objects in space, including the Sun and Moon. The Earth orbits the Sun and makes a complete revolution around it in approximately 365.26 days. This period of time is a sidereal year, which is equal to 365.26 solar days. The Earth's rotation axis is tilted 23.4° relative to its orbital plane, which causes seasonal changes on the planet's surface with a period of one tropical year (365.24 solar days). The Moon began its orbit around the Earth approximately 4.53 billion years ago, which stabilized the planet's axial tilt and is responsible for the tides that slow the Earth's rotation. Some theories suggest that asteroid impacts led to significant changes in the environment and the surface of the Earth, in particular, mass extinctions of various species of living beings.
Earth is more than 14 times less massive than the least massive gas planet, Uranus, but is about 400 times more massive than the largest known Kuiper Belt object.
Terrestrial planets consist mainly of oxygen, silicon, iron, magnesium, aluminum and other heavy elements.
All terrestrial planets have the following structure:
in the center is a core of iron mixed with nickel.
the mantle consists of silicates.
crust formed as a result of partial melting of the mantle and also consisting of silicate rocks, but enriched in incompatible elements. Of the terrestrial planets, Mercury does not have a crust, which is explained by its destruction as a result of meteorite bombardment. The Earth differs from other terrestrial planets in the high degree of chemical differentiation of matter and the wide distribution of granites in the crust.
The two outermost terrestrial planets (Earth and Mars) have satellites and (unlike all giant planets) neither of them has rings.

Internal structure of the Earth (inner and outer core, mantle, crust) following methods (seismic exploration)

The Earth, like other terrestrial planets, has a layered internal structure. It consists of hard silicate shells (crust, extremely viscous mantle), and a metallic core. The outer part of the core is liquid (much less viscous than the mantle), and the inner part is solid. Geological layers of the Earth in depth from the surface:
The planet's internal heat is most likely provided by the radioactive decay of the isotopes potassium-40, uranium-238 and thorium-232. All three elements have half-lives of more than a billion years. At the planet's center, temperatures may rise to 7,000 K and pressures may reach 360 GPa (3.6 million atm). Part of the thermal energy of the core is transferred to the earth's crust through plumes. Plumes lead to the appearance of hot spots and traps.
Earth's crust
The earth's crust is top part solid ground. It is separated from the mantle by a boundary with a sharp increase in seismic wave velocities - the Mohorovicic boundary. There are two types of crust - continental and oceanic. The thickness of the crust ranges from 6 km under the ocean to 30-50 km on the continents. In the structure of the continental crust, three geological layers are distinguished: sedimentary cover, granite and basalt. The oceanic crust is composed predominantly of basic rocks, plus sedimentary cover. The earth's crust is divided into lithospheric plates of different sizes, moving relative to each other. The kinematics of these movements is described by plate tectonics.
Mantle- this is the silicate shell of the Earth, composed mainly of peridotites - rocks consisting of silicates of magnesium, iron, calcium, etc. Partial melting of mantle rocks gives rise to basalt and similar melts, which form the earth’s crust when rising to the surface.
The mantle makes up 67% of the Earth's total mass and about 83% of the Earth's total volume. It extends from depths of 5-70 kilometers below the boundary with the earth's crust, to the boundary with the core at a depth of 2900 km. The mantle is located in a huge range of depths, and with increasing pressure in the substance, phase transitions occur, during which minerals acquire an increasingly dense structure. The most significant transformation occurs at a depth of 660 kilometers. The thermodynamics of this phase transition are such that mantle matter below this boundary cannot penetrate through it, and vice versa. Above the boundary of 660 kilometers is the upper mantle, and below, accordingly, the lower mantle. These two parts of the mantle have different compositions and physical properties. Although information about the composition of the lower mantle is limited, and the number of direct data is very small, it can be confidently stated that its composition has changed significantly less since the formation of the Earth than the upper mantle, which gave rise to the earth's crust.
Heat transfer in the mantle occurs by slow convection, through plastic deformation of minerals. The speed of movement of matter during mantle convection is on the order of several centimeters per year. This convection sets the lithospheric plates in motion (see plate tectonics). Convection in the upper mantle occurs separately. There are models that assume an even more complex structure of convection.
Earth's core
The core is the central, deepest part of the Earth, the geosphere, located under the mantle and, presumably, consisting of an iron-nickel alloy with an admixture of other siderophile elements. Depth of occurrence - 2900 km. The average radius of the sphere is 3.5 thousand km. It is divided into a solid inner core with a radius of about 1300 km and a liquid outer core with a radius of about 2200 km, between which a transition zone is sometimes distinguished. The temperature in the center of the Earth's core reaches 5000 C, the density is about 12.5 t/m?, the pressure is up to 361 GPa. Core mass - 1.932?1024 kg.
Seismic exploration- a geophysical method of studying the structure and composition of the earth's crust using artificially excited elastic waves. The main characteristic of an elastic wave is its speed - a value determined by the density, porosity, fracturing, depth and mineral composition of rocks. The difference in elastic properties between geological layers determines the presence of boundaries in the section that reflect and refract elastic waves. Secondary waves formed at the interfaces reach the observation surface, where they are recorded and converted for ease of interpretation.
Methods for determining the age of the earth and the Universe
Studying the past of our earth and the universe through the centuries using physical methods, some scientists estimate its age at billions of years, although there are a huge number of facts that refute this statement. Let's take a closer look at this issue.
After the discovery of the phenomenon of radioactivity by the French physicist Henri Becquerel at the end of the 19th century and the establishment of the laws of radioactive decay, another way to determine the absolute age of geological objects appeared. Radioisotope methods soon, if not replaced, then significantly replaced other dating methods. Firstly, they seemed to provide the possibility of an absolute determination of age, and, secondly, they gave a very large age of rocks of the order of billions of years, which suited evolutionists.
Let us consider the essence of the radioisotope dating method. Radioactive decay is like an hourglass: by the ratio of the number of atoms of the element resulting from the decay to the number of atoms of the decaying element, it is possible to determine the duration of the decay process. It is assumed that the rate of decomposition is a constant value and does not depend on temperature, pressure, chemical reactions and other external influences. The most commonly used methods are those based on argon®Pb), potassium ®lead (U®on the reactions of transformation of atomic nuclei: uranium Sr) and the radiocarbon dating method.® strontium (Rb®Ar), rubidium ®(K
Pb) is used to determine® lead (U ®Radioisotope method uranium 4.51 ~ the age of decay of nuclei of the uranium isotope U238 with a half-life of billions of years. The decay process occurs in several stages, from uranium to lead there are 14 of them:
® a Rn222 + ® a Ra226 + ® a Th230 + ® b U234 + ® b Pr234 + ® a Th234 + ®U238 Po210® b Bi210 + ® a Pb210 + ® b Po214 + ® b Bi214 + ® a Pb 214 + ® aPo218 + . and leads to the formation of the stable isotope Pb206. It is clear thata Pb206 + ® b+ the greater the ratio of the number of Pb206 atoms to the number of U238 atoms, the older the sample should be, but one must take into account the possibility of contamination of the original rock with Pb206 by lead.
For radioisotope dating, rocks like granites, which were formed by crystallization of a liquid, are selected. Such a rock can be dated and may be useful in determining the age of associated sedimentary rock or fossils within it. For example, during crystallization of zircon (ZrSiO4), atoms of the uranium isotope U238 can replace zirconium atoms in the crystal lattice. Then the U238 atoms decay, eventually turning into lead Pb206. It is clear that for correct dating it is necessary to know the initial content of the lead isotope Pb206 in the rock. It can be taken into account by assuming that the ratio of the concentrations of the isotopes Pb206 and Pb204 in zircon and the surrounding rocks that do not contain uranium is the same. Then, by the excess of the lead isotope Pb206 in zircon relative to the surrounding rock (only this lead isotope is obtained from uranium), one can determine its proportion obtained from uranium. Further, the assumption is made that there was no contamination of the samples with lead, for example, from groundwater or car exhaust, nor was there any leaching of uranium, and the age of the zircon crystals is determined from the ratio of the concentrations of the Pb206 and U238 isotopes. The above example shows how scrupulous the chemical analysis of rocks must be, what assumptions are made, and we will leave it to the reader to judge the reality of their implementation.
Ar) is important because uranium®-containing argon (K ®Radioisotope method potassium minerals are rare, but potassium-containing minerals are common. The method is based on the fact that Ar40, turning into nuclei®-decay K40bthat nuclei of the potassium isotope K40 experience argon (half-life is 1.31 billion years). The main disadvantage of this method is the penetration of argon into rocks from the atmosphere (and there is about 1% of it in the atmosphere), which they try to take into account by the ratio of the concentrations of atoms of two argon isotopes Ar40 / Ar36 present in the atmosphere. However, argon gives plausible ®not always dating using the potassium method results: when analyzing lava from the Hawaiian Islands, the age of which was known Ar, an age of 22 million years was obtained?!®and was 200 years old, according to the K method (apparently due to excess pressure underwater lavas contain more argon). error sources taken into account. Note that the potassium-argon dating method assumes a constant ratio of the concentrations of argon isotopes Ar40/Ar36 in the atmosphere over billions of years, which is unlikely, because The isotope Ar36 is formed in the atmosphere under the influence of cosmic radiation.
A common feature of the radioisotope dating methods listed above is the close values ​​of the half-lives of the isotopes used, several billion years, and the age of geological rocks corresponding to these periods. In many ways, the methods themselves determine the age obtained with their help, since these methods cannot give another age, for example, about thousands of years, just as on scales for weighing carriages and cars, it is impossible to determine the weight of a wedding ring or use them for needs pharmacology.
One should not particularly trust the consistency of the results obtained by various radioisotope methods: they are all based on the same assumptions, many of which have long been proven to be untenable. The main assumptions are:
1. The origin of the Earth in accordance with Laplace's nebular hypothesis. Laplace's hypothesis has not stood the test of time. However, for geology, the Laplace model has not been canceled today.
2. Pyrogenic (solidification of liquid) or metamorphic (crystallization of sedimentary rock) formation of crystals.
3. Closedness of the crystal after its formation.
4. Assumptions about the invariance of half-lives and the constancy of the percentage ratio between isotopes at all times.
The last assumption is extrapolation on a gigantic time scale, since the decay of nuclei is observed for only about a hundred years, and conclusions about the constancy of characteristics are generalized over billions of years, i.e. for a period of time 107 times longer. For some reason, most people are indifferent to such procedures; apparently, they have the illusion that we know our past well, but we cannot agree with this when it comes to geological times. Many simply do not realize what a billion is (after all, there are apparently no billionaires among the readers), and how it differs from a million. To make it easier to understand what times go by speech, comparable to the age of the Earth at 5.6 billion years one week. Then the Trojan War, one of the first events recorded in writing in Homer's poems, took place less than a second ago.
In addition, the independence of the half-life from external conditions does not cover all possible cases - after all, when irradiated, for example by neutrons, the decay rate of nuclei can become arbitrarily high, which is realized in an atomic bomb and nuclear reactors. Therefore, in many ways, the assumption of a constant decay rate is an act of faith, which most of the scientific community does not want to admit, convincing the few initiated, including with such terms as “decay constant,” so that there is no longer any doubt about the method. Thus, of the four assumptions, two are questionable, as is the uniformitarian concept itself, which has other weaknesses.
The radiocarbon dating method operates over significantly shorter periods of time, corresponding to the handwritten history of mankind (about 4000 years). The carbon method was developed and applied by Willard Libby, who later received the Nobel Prize for this. There are two isotopes of carbon, stable and unstable, with a half-life of 5700 years. The balance of carbon isotope concentrations is ensured by the cosmic neutron flux in + p. The idea of ​​the method as a result of the n + nuclear reaction occurring in the atmosphere is to compare the concentrations of these two isotopes (for one C14 atom there are 765,000,000,000 C12 atoms). The method is based on the assumption that this ratio has not changed over the past 50,000 years and the concentration of isotopes is the same throughout the atmosphere. After formation, the C14 isotope is almost immediately oxidized to CO2 and is included in the carbon cycle of life: plant leaves, etc. The ratio of C14/C12 isotopes does not change during the life of a plant or animal, and after death the concentration drops in accordance with the law of radioactive decay. Half-life is the time during which the number of atoms of a radioactive isotope decreases by half. Then in two periods it will decrease by four times, in three - by eight, etc. Similar reasoning leads to the general formula: over n half-lives, the number of atoms decreases by a factor of 2n. This formula sets the upper limit of applicability of the radiocarbon method at 50,000 years. Since the development of radiocarbon dating, many fossils have been dated, and none have been found that do not contain the C14 isotope. Those. All fossils were within 50,000 years old, rather than millions or billions of years old as previously thought. However, subsequently, the results of carbon dating were censored and facts that were objectionable to evolutionists were simply hushed up.
Based on a comparison of the production and decay rates of the C14 isotope within the same uniformitarian model, the age of the atmosphere, estimated from today's concentration of the C14 isotope, is limited to approximately 20,000 years.
etc.................

Subject: " How is Earth different from other planets?.

Target : to contribute to the formation of students’ knowledge about planet Earth, about its place in the solar system, about its features and differences from other planets solar system; The Moon as a satellite of the Earth; expanding ideas about the globe as a model of the Earth, the shapes of the earth's surface; ensure the development of UUD:

1) personal: motivation for learning;2) cognitive: formulating a cognitive goal, searching and isolating information, modeling, analysis to identify features, choosing grounds and criteria for comparing seriation, classifying objects, establishing cause-and-effect relationships, putting forward hypotheses and their justification,

3)communicative: assessment of the partner’s actions, the ability to express one’s thoughts with sufficient completeness and accuracy,

4) regulatory: goal setting, planning, forecasting, control, correction, evaluation;education of moral sense, ethical consciousness and readiness to perform positive actions, including speech;

cognitive abilities; environmental education; aesthetic education.

Equipment: educational presentation, table “Comparison of the planets of the solar system”, globe, equipment for the experiment: ball, flashlight, texts for group work

I. Motivation (self-determination) for educational activities.

What science deals with the knowledge of the starry sky? (Children's answers.)

What are scientists who study the starry sky called? (Children's answers.)

What are the names of great scientists - astronomers? (N. Copernicus.)

Do you also want to learn something new about space and planets?

Let's try to become researchers too.

The motto of our lesson: “Borders scientific knowledge and it is impossible to predict.” This is a statement by the great Russian scientist Dmitry Ivanovich Mendeleev.

- How do you understand these words?

ΙI. Updating knowledge, defining a topic and setting an educational problem

1.Guess the riddles and try to determine the topic of today's lesson.

There is one garden planet
In this cold space.
Only here the forests are noisy,
Calling migratory birds,
It's the only one they bloom on
Lilies of the valley in the green grass,
And dragonflies are only here
They look into the river in surprise...

Alone in the sky at night
Golden orange.
Two weeks have passed
We didn't eat orange
But only remained in the sky
Orange slice.

Stands on one leg
He twists and turns his head.
Shows us countries
Rivers, mountains, oceans.

What is the relationship between the clue words?

Topic: How is Earth different from other planets?

–What problems will we solve in class?

Why is life possible on Earth?

Globe is a model of the Earth.

The Moon is the Earth's satellite.

What do you already know about this topic?

– What question interested you most?

– Why?

What will we do in class to achieve the assigned tasks?

What research methods will help us find necessary information?

Regulatory UUD:

1) we develop the ability to determine the purpose of activity in the lesson;

2)

Cognitive UUD:

1) features of objects;

2)

3)

4)

ΙΙI. Collaborative discovery of knowledge

What is the best way to organize research?

Why do you like working in a group?

As the lesson progresses, we will evaluate our work on self-assessment sheets.

Self-assessment sheet

Types of activities in the lesson

Performance evaluation

Done it myself

There were difficulties

Completed with the help of friends

Defining a theme

Staging educational task

Planning

Learning new material

Group work

Research route on the board

1. Research “How is the Earth different from other planets?”

Table “Comparison of the planets of the solar system.” (Additional material.)

Review the table. What interested you? What questions have arisen? (Brief explanations from the teacher.)

Read the names of the planets. (Children's answers.)

Name

planets

Surface temperature

Length of day (in Earth

days)

Period

appeals

in orbit

(in years)

Planet from the Sun

Quantity

satellites

Max. Min.

Mercury

480 -180

58,65

0,24

first

Venus

480

243

0,62

second

Earth

58 - 90

third

Mars

0 150

1,03

1,88

fourth

Jupiter

160 - 160

0,41

11,86

fifth

Saturn

150 - 150

0,44

29,46

sixth

Uranus

220 -220

0,72

seventh

Neptune

213 -213

0,74

165

eighth

Pluto

230 - 230

6,4

247,7

ninth

2. Analysis of data from the “Surface temperature” column.

Determine on which planets life is possible and on which not?

What other conditions are necessary for life besides air temperature?

Let's learn about this from the textbook. p.12

3. Working with a textbook article.

What new scientific data does the article “How does the Earth differ from other planets?” contain? (p.12) Conclusion. (find on touch crosses)

Physical education minute (clip “Grass near the house”)

2.- Let's turn to the research route.

Globe is a model of the Earth.

Etcactive work of students p. 17 textbook

Why is the globe multi-colored?

What can the colors of the globe tell you?(the color of the globe indicates the shape of the surface - sea and land)

What color is there more on the globe?

3. - Let's turn to the research route.

The Moon is the Earth's satellite.

What does the word satellite mean? (lexical meaning of the word)

Working with a dictionary.

a) Observation of the Moon. (look at the slide)

What does the Moon look like?

b) Working with text p.14

What does the Moon look like?

Are there seas on the Moon?

What are the names of the mountains on the Moon?

c) Conducting the experiment. p. 15 of the textbook

Why does the Moon change its appearance?

What will the “Moon” look like when rotating, if you look at it from the “Earth”?

Students discuss the results of the experiment and draw a conclusion:

The Moon moves around the Earth, and we see that part of it that is illuminated by the Sun at that moment.

Cognitive UUD:

1) we develop the ability to extract information from diagrams, illustrations, text, tables;

2) We develop the ability to present information in the form of a diagram;

3) We develop the ability to identify the essence,features of objects;

4) we develop the ability to draw conclusions based on the analysis of objects;

5) we develop the ability to establish analogies;

6) We develop the ability to generalize and classify according to characteristics.

Communication UUD:

1) We develop the ability to listen and understand others;

2) we develop the ability to construct a speech statement in accordance with the assigned tasks;

3) We develop the ability to formulate our thoughts in orally;

4) We develop the ability to jointly agree on the rules of communication and behavior.

Personal UUD:

1) We develop the ability to identify and express the simplest rules common to all people.

ΙV. Application of new knowledge

Group work

Exploring the possibility of life on imaginary planets.

Work with texts, discussion: is it possible to live on this planet? Prove it.

1 group

Our ship landed on the planet. A huge icy desert appeared before our eyes. The temperature on the planet does not rise above -29 degrees, but can drop to -85 degrees. The small amount of water that is on the planet is in a permanently frozen state. Cold wind didn't give me a chance to go. We hastened to leave the inhospitable planet.

2nd group

Our ship landed, and a huge desert appeared before our eyes. There was a breeze, but it was unbearably hot. In search of water, our expedition explored a vast territory. There was no water. We didn't meet any animals. Only here and there were plants that looked somewhat like cacti sticking out of the sand. The wind drove clouds of dust, it became difficult to breathe. Due to the sandstorm, we could not see anything and had difficulty getting to our ship.

3 group

The surface of the planet was covered with low mountains. It was warm, and we noticed unusual animals that looked something like lizards. They basked peacefully in the sun and looked at us with their big round eyes. We continued our journey and discovered a small lake. There was water in it Brown, but there were no plants around. But then a muddy rain began to fall, and we hurried to our ship.

Compiling a syncwine

Line 1 – heading, which contains the keyword, concept, theme of the syncwine, expressed in the form of a noun.
Line 2 – two adjectives.
Line 3 – three verbs.
Line 4 is a phrase that carries a certain meaning.
Line 5 – summary, conclusion, one word, noun.

Planet Earth,

spherical, blue,

rotates, illuminates, warms

3rd planet after the sun

life

Regulatory UUD:

1) we develop the ability to determine the success of completing our task in dialogue with the teacher;

2)

3)

Spiritual and moral development and education:

1) education of moral sense, ethical consciousness and readiness to perform positive actions, including speech;

3) education of hard work and ability to learn;

4) environmental education;

5) aesthetic education.

V. Lesson summary

– What new did you learn in the lesson?

– What questions were answered?

– Which ones are left?

– Where can you find answers to these questions? (If there are any left .)

– When might the knowledge from today's lesson be useful to you?

– What conclusion did you draw?

– What work did we do today?

– What have you learned?

– Who or what helped you cope?

– Who is happy with their job today?

Regulatory UUD:

1) we develop the ability to determine the success of completing our task in dialogue with the teacher;

2) we develop the ability to evaluate educational actions in accordance with the assigned task;

3) We develop the ability to carry out cognitive and personal reflection.

Lesson about the world around us in 2nd grade. Topic: “How does the Earth differ from other planets.”
date
Teacher Parshina I.A.
Goal: to contribute to the formation of students’ knowledge about planet Earth, about its place in the solar system, about its features and differences from other planets of the solar system; The Moon as a satellite of the Earth; expanding ideas about the globe as a model of the Earth, the shapes of the earth's surface; ensure the development of UUD:
1) personal: motivation for learning; 2) cognitive: formulating a cognitive goal, searching and isolating information, modeling, analysis to identify features, choosing bases and criteria for comparing seriation, classifying objects, establishing cause-and-effect relationships, putting forward hypotheses and their justification, 3) communicative: evaluating actions partner, the ability to express one’s thoughts with sufficient completeness and accuracy,
4) regulatory: goal setting, planning, forecasting, control, correction, evaluation; education of moral sense, ethical consciousness and readiness to perform positive actions, including speech; cognitive abilities; environmental education; aesthetic education.

Lesson steps
During the classes
Formation of UUD

I. Motivation (self-determination) for educational activities.

What science deals with the knowledge of the starry sky? (Children's answers.)
- What do scientists who study the starry sky call? (Children's answers.)
- What are the names of great scientists - astronomers? (N. Copernicus.)
- Do you also want to learn something new about space and planets?
- Let's try to become researchers too.
The motto of our lesson: “It is impossible to foresee the boundaries of scientific knowledge and prediction.” This is a statement by the great Russian scientist Dmitry Ivanovich Mendeleev.
- How do you understand these words?

·I. Updating knowledge, defining a topic and setting an educational problem

1.Guess the riddles and try to determine the topic of today's lesson.
There is one garden planet in this cold space. Only here the forests are noisy, calling migrating birds, only here lilies of the valley bloom in the green grass, and only here are dragonflies looking into the river in surprise...
At night there is only one golden orange in the sky. Two weeks passed, We didn’t eat any orange, But only an orange slice remained in the sky.
He stands on one leg, twists and turns his head. Shows us countries, rivers, mountains, oceans.
- What is the relationship between the guessing words?
Topic: How is Earth different from other planets?
-What problems will we solve in class?
Why is life possible on Earth?
Globe is a model of the Earth.
The Moon is the Earth's satellite.
- What do you already know about this topic?
– What question interested you most?
- Why?
- What will we do in class to achieve the assigned tasks?
- What research methods will help us find the information we need?
Regulatory UUD:
1) we develop the ability to determine the purpose of activity in the lesson;
2) we develop the ability to determine the success of completing one’s task in dialogue with the teacher;

Cognitive UUD:
1) we develop the ability to identify the essence and features of objects;
2) we develop the ability to draw conclusions based on the analysis of objects;
3) we develop the ability to establish analogies;
4) we develop the ability to generalize and classify according to characteristics.

·
·I. Collaborative discovery of knowledge

What is the best way to organize research?
- Why do you like working in a group?
- As the lesson progresses, we will evaluate our work on self-assessment sheets.
Self-assessment sheet
Types of activities in the lesson
Performance evaluation

Done it myself
There were difficulties
Completed with the help of friends

Defining a theme

Setting a learning task

Planning

Learning new material

Group work

Research route on the board
1. Research “How is the Earth different from other planets?”
Table “Comparison of the planets of the solar system.” (Additional material.)
- Look at the table. What interested you? What questions have arisen? (Brief explanations from the teacher. Read the names of the planets. (Children’s answers.)
Name
planets
Surface temperature

Length of day (in Earth
days)
Period
appeals
in orbit
(in years)
Planet from the Sun
Quantity
satellites

Max. Min.

Mercury
+480 -180
58,65
0,24
first
0

Venus
+480
243
0,62
second
0

Earth
+58 - 90
1
1
third
1

Mars
0 - 150
1,03
1,88
fourth
2

Jupiter
-160 -160
0,41
11,86
fifth
16

Saturn
-150 - 150
0,44
29,46
sixth
17

Uranus
-220 -220
0,72
84
seventh
15

Neptune
-213 -213
0,74
165
eighth
6

Pluto
-230 - 230
6,4
247,7
ninth
1

2. Analysis of data from the “Surface temperature” column.
- Determine on which planets life is possible and on which not?
- What other conditions are necessary for life, besides air temperature?
- We learn about this from the textbook. p.12
3. Working with a textbook article.
- What new scientific data does the article “Than the Earth” contain?