6 what planet is from the sun? Earth's little brother - the fourth planet from the Sun

This is a system of planets, in the center of which there is a bright star, a source of energy, heat and light - the Sun.
According to one theory, the Sun was formed along with the solar system about 4.5 billion years ago as a result of the explosion of one or more supernovae. Initially, the Solar System was a cloud of gas and dust particles, which, in motion and under the influence of their mass, formed a disk in which a new star, the Sun, and our entire Solar System arose.

To the center solar system There is the Sun, around which nine large planets revolve in orbits. Since the Sun is displaced from the center of planetary orbits, during the cycle of revolution around the Sun the planets either approach or move away in their orbits.

Terrestrial planets: And . These planets are small in size with a rocky surface and are closest to the Sun.

Giant planets: And . These are large planets, consisting mainly of gas and characterized by the presence of rings consisting of icy dust and many rocky pieces.

But does not fall into any group because, despite its location in the solar system, it is located too far from the Sun and has a very small diameter, only 2320 km, which is half the diameter of Mercury.

Planets of the Solar System

Let's begin a fascinating acquaintance with the planets of the Solar System in order of their location from the Sun, and also consider their main satellites and some other space objects (comets, asteroids, meteorites) in the gigantic expanses of our planetary system.

Rings and moons of Jupiter: Europa, Io, Ganymede, Callisto and others...
The planet Jupiter is surrounded by a whole family of 16 satellites, and each of them has its own unique features...

Rings and moons of Saturn: Titan, Enceladus and others...
Not only the planet Saturn has characteristic rings, but also other giant planets. Around Saturn, the rings are especially clearly visible, because they consist of billions of small particles that revolve around the planet, in addition to several rings, Saturn has 18 satellites, one of which is Titan, its diameter is 5000 km, which makes it the largest satellite in the solar system...

Rings and moons of Uranus: Titania, Oberon and others...
The planet Uranus has 17 satellites and, like other giant planets, there are thin rings surrounding the planet that have practically no ability to reflect light, so they were discovered not so long ago in 1977, completely by accident...

Rings and moons of Neptune: Triton, Nereid and others...
Initially, before the exploration of Neptune by the Voyager 2 spacecraft, two satellites of the planet were known - Triton and Nerida. Interesting fact that the satellite Triton has the opposite direction orbital movement, strange volcanoes were also discovered on the satellite, which erupted nitrogen gas like geysers, spreading a dark-colored mass (from liquid to vapor) many kilometers into the atmosphere. During its mission, Voyager 2 discovered six more moons of the planet Neptune...

solar system is a system of celestial bodies welded together by forces of mutual attraction. It includes: the central star - the Sun, 8 large planets with their satellites, several thousand small planets, or asteroids, several hundred observed comets and countless meteoroids, dust, gas and small particles . It was formed by gravitational compression gas and dust cloud approximately 4.57 billion years ago.

In addition to the Sun, the system includes the following eight major planets:

Sun

The Sun is the closest star to Earth; all the others are immeasurably further away from us. For example, the closest star to us is Proxima from the system a Centauri is 2500 times farther than the Sun. For the Earth, the Sun is a powerful source of cosmic energy. It provides the light and heat necessary for flora and fauna, and forms the most important properties of the Earth's atmosphere.. In general, the Sun determines the ecology of the planet. Without it, there would be no air necessary for life: it would turn into a liquid nitrogen ocean around frozen waters and icy land. For us earthlings, the most important feature of the Sun is that our planet arose near it and life appeared on it.

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Mercury is the planet closest to the Sun.

The ancient Romans considered Mercury the patron of trade, travelers and thieves, as well as the messenger of the gods. It is not surprising that a small planet, quickly moving across the sky following the Sun, received his name. Mercury has been known since ancient times, but ancient astronomers did not immediately realize that they saw the same star in the morning and evening. Mercury is closer to the Sun than the Earth: the average distance from the Sun is 0.387 AU, and the distance to Earth ranges from 82 to 217 million km. The inclination of the orbit to the ecliptic i = 7° is one of the largest in the Solar System. Mercury's axis is almost perpendicular to the plane of its orbit, and the orbit itself is very elongated (eccentricity e = 0.206). The average speed of Mercury's orbit is 47.9 km/s. Due to the tidal influence of the Sun, Mercury fell into a resonant trap. The period of its revolution around the Sun (87.95 Earth days), measured in 1965, relates to the period of rotation around its axis (58.65 Earth days) as 3/2. Mercury completes three full revolutions around its axis in 176 days. During the same period, the planet makes two revolutions around the Sun. Thus, Mercury occupies the same position in orbit relative to the Sun, and the orientation of the planet remains the same. Mercury has no satellites. If they were, then during the formation of the planets they fell on protomercury. The mass of Mercury is almost 20 times less than the mass of the Earth (0.055M or 3.3 10 23 kg), and its density is almost the same as that of the Earth (5.43 g/cm3). The radius of the planet is 0.38R (2440 km). Mercury is smaller than some of the moons of Jupiter and Saturn.

Venus

The second planet from the Sun, has an almost circular orbit. It passes closer to Earth than any other planet.

But the dense, cloudy atmosphere does not allow you to directly see its surface. Atmosphere: CO 2 (97%), N2 (approx. 3%), H 2 O (0.05%), impurities CO, SO 2, HCl, HF. Thanks to the greenhouse effect, the surface temperature heats up to hundreds of degrees. The atmosphere, which is a thick blanket of carbon dioxide, traps heat coming from the Sun. This results in the temperature of the atmosphere being much higher than in the oven. Radar images show a very wide variety of craters, volcanoes and mountains. There are several very large volcanoes, up to 3 km high. and hundreds of kilometers wide. The outpouring of lava on Venus takes much longer than on Earth. The pressure at the surface is about 107 Pa. The surface rocks of Venus are similar in composition to terrestrial sedimentary rocks.
Finding Venus in the sky is easier than any other planet. Its dense clouds reflect sunlight well, making the planet bright in our sky. For a few weeks every seven months, Venus is the brightest object in the western sky in the evenings. Three and a half months later, it rises three hours earlier than the Sun, becoming the sparkling “morning star” of the eastern sky. Venus can be observed an hour after sunset or an hour before sunrise. Venus has no satellites.

Earth

Third from Sol ntsa planet. The speed of the Earth's revolution in an elliptical orbit around the Sun is 29.765 km/s. The inclination of the earth's axis to the ecliptic plane is 66 o 33 "22". The Earth has a natural satellite - the Moon. The Earth has a magnetic fieldital and electric fields. The Earth was formed 4.7 billion years ago from gas dispersed in the protosolar system-dust substances. The composition of the Earth is dominated by: iron (34.6%), oxygen (29.5%), silicon (15.2%), magnesium (12.7%). The pressure in the center of the planet is 3.6 * 10 11 Pa, the density is about 12,500 kg/m 3, the temperature is 5000-6000 o C. Most of the timeThe surface is occupied by the World Ocean (361.1 million km 2; 70.8%); the land area is 149.1 million km 2 and forms six motherscoves and islands. It rises above the level of the world's oceans by an average of 875 meters (the highest altitude is 8848 meters - the city of Chomolungma). Mountains occupy 30% of the land, deserts cover about 20% of the land surface, savannas and woodlands - about 20%, forests - about 30%, glaciers - 10%. The average depth of the ocean is about 3800 meters, the greatest is 11022 meters (Mariana Trench in Pacific Ocean), water volume is 1370 million km 3, average salinity is 35 g/l. The Earth's atmosphere, the total mass of which is 5.15 * 10 15 tons, consists of air - a mixture of mainly nitrogen (78.1%) and oxygen (21%), the rest is water vapor, carbon dioxide, noble and other gases. About 3-3.5 billion years ago, as a result of the natural evolution of matter, life arose on Earth and the development of the biosphere began.

Mars

The fourth planet from the Sun, similar to Earth, but smaller and cooler. Mars has deep canyonsgiant volcanoes and vast deserts. There are two small moons flying around the Red Planet, as Mars is also called: Phobos and Deimos. Mars is the next planet after the Earth, if you count from the Sun, and the only cosmic world besides the Moon that can already be reached with the help of modern rockets. For astronauts, this four-year journey could represent the next frontier in space exploration. Near the equator of Mars, in an area called Tharsis, there are volcanoes of colossal size. Tarsis is the name that astronomers gave to the hill, which has 400 km. wide and about 10 km. in height. There are four volcanoes on this plateau, each of which is simply gigantic compared to any volcano on earth. The largest volcano on Tharsis, Mount Olympus, rises 27 km above the surrounding area. About two-thirds of Mars' surface is mountainous, with many impact craters surrounded by rock debris. Near the volcanoes of Tharsis, a vast system of canyons snakes around the length of about a quarter of the equator. The Valles Marineris is 600 km wide, and its depth is such that Mount Everest would sink entirely to its bottom. Sheer cliffs rise thousands of meters, from the valley floor to the plateau above. In ancient times, there was a lot of water on Mars; large rivers flowed across the surface of this planet. There are ice caps at the South and North Poles of Mars. But this ice does not consist of water, but of frozen atmospheric carbon dioxide (freezes at a temperature of -100 o C). Scientists believe that surface water is stored in the form of ice blocks buried in the ground, especially in polar regions. Atmospheric composition: CO 2 (95%), N 2 (2.5%), Ar (1.5 - 2%), CO (0.06%), H 2 O (up to 0.1%); pressure at the surface is 5-7 hPa. In total, about 30 interplanetary space stations were sent to Mars.

Jupiter

The fifth planet from the Sun, the largest planet in the Solar System. Jupiter is not a rocky planet. Unlike the four rocky planets closest to the Sun, Jupiter is a gas ball. Atmospheric composition: H 2 (85%), CH 4, NH 3, He (14%). Jupiter's gas composition is very similar to the sun's. Jupiter is a powerful source of thermal radio emission. Jupiter has 16 satellites (Adrastea, Metis, Amalthea, Thebe, Io, Lysithea, Elara, Ananke, Karme, Pasiphae, Sinope, Europa, Ganymede, Callisto, Leda, Himalia), as well as a ring 20,000 km wide, almost closely adjacent to planet. Jupiter's rotation speed is so high that the planet bulges along the equator. In addition, this rapid rotation causes very strong winds in the upper atmosphere, where clouds stretch out into long, colorful ribbons. There are a very large number of vortex spots in the clouds of Jupiter. The largest of them, the so-called Great Red Spot, is larger than the Earth. The Great Red Spot is a huge storm in Jupiter's atmosphere that has been observed for 300 years. Inside the planet, under enormous pressure, hydrogen turns from a gas into a liquid, and then from a liquid into a solid. At a depth of 100 km. there is a boundless ocean of liquid hydrogen. Below 17,000 km. hydrogen is compressed so tightly that its atoms are destroyed. And then it begins to behave like metal; in this state it easily conducts electricity. The electric current flowing in metallic hydrogen creates a strong magnetic field around Jupiter.

Saturn

The sixth planet from the Sun has an amazing ring system. Due to its rapid rotation around its axis, Saturn seems to be flattened at the poles. Wind speeds at the equator reach 1800 km/h. The width of Saturn's rings is 400,000 km, but they are only a few tens of meters thick. The inner parts of the rings rotate around Saturn faster than the outer ones. The rings are primarily made up of billions of small particles, each orbiting Saturn as its own microscopic satellite. These "micro-satellites" are likely made of water ice or rocks covered in ice. Their size ranges from several centimeters to tens of meters. The rings contain more large objects- stone blocks and fragments up to hundreds of meters in diameter. The gaps between the rings arise under the influence of the gravitational forces of seventeen moons (Hyperion, Mimas, Tethys, Titan, Enceladus, etc.), which cause the rings to split. The composition of the atmosphere includes: CH 4, H 2, He, NH 3.

Uranus

Seventh from Sun planet. It was discovered in 1781 by the English astronomer William Herschel, and named after Greek about the sky god Uranus. The orientation of Uranus in space differs from the other planets of the solar system - its axis of rotation lies, as it were, “on its side” relative to the plane of revolution of this planet around the Sun. The axis of rotation is inclined at an angle of 98 o. As a result, the planet faces the Sun alternately with the north pole, the south, the equator, and the middle latitudes. Uranus has more than 27 satellites (Miranda, Ariel, Umbriel, Titania, Oberon, Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, Peck, etc.) and a system of rings. At the center of Uranus is a core made of rock and iron. The composition of the atmosphere includes: H 2, He, CH 4 (14%).

Neptune

E Its orbit intersects with Pluto's orbit in some places. The equatorial diameter is the same as that of Uranus, although ra Neptune is located 1627 million km further from Uranus (Uranus is located 2869 million km from the Sun). Based on these data, we can conclude that this planet could not be noticed in the 17th century. One of the striking achievements of science, one of the evidence of the unlimited cognition of nature was the discovery of the planet Neptune through calculations - “at the tip of a pen.” Uranus, the planet next to Saturn, which for many centuries was considered the most distant planet, was discovered by W. Herschel at the end of the 18th century. Uranus is hardly visible to the naked eye. By the 40s of the XIX century. accurate observations have shown that Uranus barely noticeably deviates from the path it should follow, taking into account the disturbances from everyone known planets. Thus, the theory of the movement of celestial bodies, so strict and accurate, was put to the test. Le Verrier (in France) and Adams (in England) suggested that if disturbances from the known planets do not explain the deviation in the movement of Uranus, it means that the attraction of an as yet unknown body acts on it. They almost simultaneously calculated where behind Uranus there should be an unknown body producing these deviations with its gravity. They calculated the orbit of the unknown planet, its mass and indicated the place in the sky where given time there must have been an unknown planet. This planet was found through a telescope at the place they indicated in 1846. It was named Neptune. Neptune is not visible to the naked eye. On this planet, winds blow at speeds of up to 2400 km/h, directed against the rotation of the planet. These are the strongest winds in the solar system.
Atmospheric composition: H 2, He, CH 4. Has 6 satellites (one of them is Triton).
Neptune is the god of the seas in Roman mythology.

Previously, a planet was any cosmic body that orbits a star, emits light that is reflected by that star, and is larger than an asteroid. Back in Ancient Greece they talked about 7 planets as luminous bodies that move across the sky against the background of stars. These are Mercury, Sun, Venus, Mars, Moon, Jupiter, Saturn. Please note that the Sun is indicated here, which is a star, and the Moon is a satellite of our Earth. The earth is not included in this list because the Greeks considered it the center of everything.

In the 15th century, Copernicus discovered that the center of the system was the Sun, not the Earth. He laid out his statements in his work “On the Revolution of the Celestial Spheres.” The Moon and Sun were removed from the list, and planet Earth was included. When telescopes were invented, three more planets were discovered. Uranus in 1781, Neptune in 1846, Pluto in 1930, which, by the way, is no longer considered a planet.

At the moment, researchers are giving a new meaning to the word “planet”, namely: it is a celestial body that satisfies 4 conditions:

• The body must rotate around the star.
• Have a spherical or close to it shape, that is, the body must have sufficient gravity.
• It doesn't have to be a star.
• The celestial body should not have other large bodies near its orbit.

A star is a body that emits light and has a powerful source of energy.

Planets in the Solar System

The solar system includes the planets and other objects that orbit the sun. 4.5 billion years ago, condensations of clouds of stellar matter began to form in the Galaxy. The gases heated up and radiated heat. As a result of an increase in temperature and density, nuclear reactions began, hydrogen turned into helium. This is how it arose most powerful source energy – the Sun. This process took tens of millions of years. Planets with satellites were created. The formation of the solar system ended completely about 4 billion years ago.

Today, the solar system includes 8 planets, which are divided into two groups. The first is the terrestrial group, the second is the gas giants. The terrestrial planets - Venus, Mercury, Mars and Earth - are composed of silicates and metals. The gas giants - Saturn, Jupiter, Neptune and Uranus - are composed of hydrogen and helium. The planets have different sizes, both in comparison between the two groups and among themselves. Accordingly, the giants are much larger and more massive than the terrestrial planets.

Mercury is closest to the Sun, followed by Neptune. Before characterizing the planets of the Solar System, we need to talk about its main object - the Sun. This is the star through which all living and nonliving things in the system began to exist. The sun is a spherical, plasma, hot ball. A large number of space objects revolve around it - satellites, planets, meteorites, asteroids and cosmic dust. This star appeared about 5 billion years ago. Its mass is 300 thousand times greater than the mass of our planet. The core temperature is 13 million degrees Kelvin, and at the surface - 5 thousand degrees Kelvin (4727 degrees Celsius). In the Milky Way galaxy, the Sun is one of the largest and bright stars. The distance from the Sun to the center of the Galaxy is 26,000 light years. The Sun makes a complete revolution around the galactic center every 230-250 million years.

Mercury

It is closest to the Sun and is the smallest planet in the solar system. The planet has no satellites. There are many craters on the surface of Mercury, which were formed by many meteorites that fell on the planet more than 3 billion years ago. Their diameter is varied - from a couple of meters to 1000 kilometers. The planet's atmosphere is composed mainly of helium and is blown by wind from the Sun. Temperatures can reach +440 degrees Celsius. The planet completes a revolution around the Sun in 88 Earth days. A day on the planet is equal to 176 Earth hours.

Venus

Venus is the second planet from the Sun. Its dimensions are close to the size of the Earth. The planet has no satellites. The atmosphere consists of carbon dioxide with admixtures of nitrogen and oxygen. The air pressure is 90 atmospheres, which is 35 times more than on Earth. Venus is called the hottest planet because its dense atmosphere, carbon dioxide, proximity to the Sun and the greenhouse effect create very high temperatures on the planet's surface. It can reach 460 degrees Celsius. Venus can be seen from the surface of the Earth. This is the brightest cosmic object after the Moon and the Sun.

Earth

The only planet suitable for life. Maybe it exists on other planets, but no one can say this with certainty yet. It is the largest in its group in terms of mass, density and size. Its age is more than 4 billion years. Life began here more than 3 billion years ago. Earth's satellite is the Moon. The atmosphere on the planet is radically different from others. Most of it consists of nitrogen. This also includes carbon dioxide, oxygen, water vapor and argon. The ozone layer and magnetic field make the level of solar and cosmic radiation less. Due to the content of carbon dioxide in the Earth's atmosphere, a greenhouse effect is formed on the planet. Without it, the temperature on the Earth's surface would be 40 degrees lower. Islands and continents occupy 29% of the planet's surface, and the rest is the World Ocean.

Mars

It is also called the “red planet” due to the presence of large amounts of iron oxide in the soil. Mars is the seventh largest planet in the solar system. Two satellites fly near the planet - Deimos and Phobos. Due to the too thin atmosphere and the far distance from the Sun, the average annual temperature of the planet is minus 60 degrees. At some points during the day, temperature changes can reach 40 degrees. The presence of volcanoes and craters, deserts and valleys, and polar ice caps distinguishes Mars from other planets in the solar system. Also here is the highest mountain - the extinct Olympus volcano, which reached a height of 27 kilometers. Valles Marineris is the largest canyon among the planets. Its length is 4500 km and its depth is 11 m.

Jupiter

This is the most major planet in the Solar System. Jupiter is 318 times heavier than Earth and 2.5 times more massive compared to other planets. The main components of the planet are helium and hydrogen. Jupiter emits a lot of heat - 4 * 1017 W. To become a star like the Sun, it must reach 70 times its current mass. The planet has the largest number of satellites - 63. Europa, Callisto, Ganymede and Io are the largest of them. Ganymede is also the largest moon in the entire solar system and is even larger than Mercury. Jupiter's atmosphere hosts many vortices that have a brownish-red colored band of clouds, or a giant storm, known as the Great Red Spot since the 17th century.

Saturn

Like Jupiter, it is a large planet that follows Jupiter in size. The ring system, which consists of particles of ice of various sizes, rocks and dust, distinguishes this planet from others. It has one fewer satellites than Jupiter. The largest are Enceladus and Titan. In composition, Saturn resembles Jupiter, but in density it is inferior to the simplest water. The atmosphere looks quite homogeneous and calm, which can be explained by a dense layer of fog. Saturn has enormous wind speeds, it can reach 1800 km per hour.

Uranus

This planet was discovered first using a telescope. Uranus is the only planet in the solar system that lies on its side and orbits the sun. Uranus has 27 moons, which are named after characters in Shakespeare's plays. The largest among them are Titania, Oberon and Umbriel. Uranus contains a large number of high-temperature modifications of ice. It is also the coldest planet. The temperature here is minus 224 degrees Celsius.

Neptune

This is the most distant planet from the Sun, although until 2006 this title belonged to Pluto. This planet was discovered without the help of a telescope, but by mathematical calculations. The existence of Neptune was suggested to scientists by Uranus, on which strange changes were discovered while moving in its own orbit. The planet has 13 satellites. The largest among them is Triton. Its peculiarity is that it moves opposite to the planet. The strongest winds in the solar system blow in the same direction, the speed of which reaches 2200 km per hour. Neptune and Uranus have similar compositions, but it is also similar in composition to Jupiter and Saturn. The planet has internal source heat, from which it receives 2.5 times more energy than from the Sun. There is methane in the outer layers of the atmosphere, which gives the planet a blue tint.

That's how mysterious the world of Space is. Many satellites and planets have their own characteristics. Scientists are making changes to this world, for example, they excluded Pluto from the list of planets.

Study the planets on the portal website - it’s very interesting.

Rotation of planets

All planets, in addition to their orbit, also rotate around their own axis. The period during which they make a full revolution is defined as an epoch. More planets in the solar system rotate in the same direction around the axis as around the sun, but Uranus and Venus rotate in the opposite direction. Scientists observe a big difference in the length of the day on the planets - Venus takes 243 Earth days to complete one revolution around its axis, while the gas giant planets need only a couple of hours. The rotation period of exoplanets is unknown, but their close proximity to the stars means that eternal day reigns on one side, and eternal night on the other.

Why are all the planets so different? Due to the high temperature closer to the star, the ice and gas evaporated very quickly. The giant planets failed to form, but an accumulation of metal particles occurred. Thus, Mercury was formed, which contains the largest amount of metals. The further we are from the center, the lower the temperature. Appeared celestial bodies, where a significant percentage was made up of rocks. The four planets that are located closer to the center of the solar system are called the inner ones. With the discovery of new systems, more and more questions arise. New research will help answer them.

Scientists claim that our system is unique. All planets are built in strict order. The largest one is closer to the Sun, respectively, the smallest one is further away. Our system has a more complex structure, because the planets are not arranged according to their mass. The sun makes up more than 99 percent of all objects in the system.

Universe (space)- this is the entire world around us, limitless in time and space and infinitely varied in the forms that eternally moving matter takes. The boundlessness of the Universe can be partially imagined on a clear night with billions of different sizes of luminous flickering points in the sky, representing distant worlds. Rays of light at a speed of 300,000 km/s from the most distant parts of the Universe reach the Earth in about 10 billion years.

According to scientists, the Universe was formed as a result of the “Big Bang” 17 billion years ago.

It consists of clusters of stars, planets, cosmic dust and other cosmic bodies. These bodies form systems: planets with satellites (for example, the solar system), galaxies, metagalaxies (clusters of galaxies).

Galaxy(late Greek galaktikos- milky, milky, from Greek gala- milk) is a vast star system that consists of many stars, star clusters and associations, gas and dust nebulae, as well as individual atoms and particles scattered in interstellar space.

There are many galaxies of different sizes and shapes in the Universe.

All stars visible from Earth are part of the Milky Way galaxy. It got its name due to the fact that most stars can be seen on a clear night in the form of the Milky Way - a whitish, blurry stripe.

In total, the Milky Way Galaxy contains about 100 billion stars.

Our galaxy is in constant rotation. The speed of its movement in the Universe is 1.5 million km/h. If you look at our galaxy from its north pole, the rotation occurs clockwise. The Sun and the stars closest to it complete a revolution around the center of the galaxy every 200 million years. This period is considered to be galactic year.

Similar in size and shape to the Milky Way galaxy is the Andromeda Galaxy, or Andromeda Nebula, which is located at a distance of approximately 2 million light years from our galaxy. Light year— the distance traveled by light in a year, approximately equal to 10 13 km (the speed of light is 300,000 km/s).

To visualize the study of the movement and location of stars, planets and other celestial bodies, the concept is used celestial sphere.

Rice. 1. Main lines of the celestial sphere

Celestial sphere is an imaginary sphere of arbitrarily large radius, in the center of which the observer is located. The stars, Sun, Moon, and planets are projected onto the celestial sphere.

The most important lines on the celestial sphere are: the plumb line, zenith, nadir, celestial equator, ecliptic, celestial meridian, etc. (Fig. 1).

Plumb line- a straight line passing through the center of the celestial sphere and coinciding with the direction of the plumb line at the observation point. For an observer on the Earth's surface, a plumb line passes through the center of the Earth and the observation point.

A plumb line intersects the surface of the celestial sphere at two points - zenith, above the observer's head, and nadire - diametrically opposite point.

The great circle of the celestial sphere, the plane of which is perpendicular to the plumb line, is called mathematical horizon. It divides the surface of the celestial sphere into two halves: visible to the observer, with the vertex at the zenith, and invisible, with the vertex at the nadir.

The diameter around which the celestial sphere rotates is axis mundi. It intersects with the surface of the celestial sphere at two points - north pole of the world And south pole of the world. The north pole is the one from which the celestial sphere rotates clockwise when looking at the sphere from the outside.

The great circle of the celestial sphere, the plane of which is perpendicular to the axis of the world, is called celestial equator. It divides the surface of the celestial sphere into two hemispheres: northern, with its summit at the north celestial pole, and southern, with its peak at the south celestial pole.

The great circle of the celestial sphere, the plane of which passes through the plumb line and the axis of the world, is the celestial meridian. It divides the surface of the celestial sphere into two hemispheres - eastern And western.

The line of intersection of the plane of the celestial meridian and the plane of the mathematical horizon - noon line.

Ecliptic(from Greek ekieipsis- eclipse) is a large circle of the celestial sphere along which the visible annual movement of the Sun, or more precisely, its center, occurs.

The plane of the ecliptic is inclined to the plane of the celestial equator at an angle of 23°26"21".

To make it easier to remember the location of stars in the sky, people in ancient times came up with the idea of ​​combining the brightest of them into constellations.

Currently, 88 constellations are known, which bear the names of mythical characters (Hercules, Pegasus, etc.), zodiac signs (Taurus, Pisces, Cancer, etc.), objects (Libra, Lyra, etc.) (Fig. 2).

Rice. 2. Summer-autumn constellations

Origin of galaxies. The solar system and its individual planets still remain an unsolved mystery of nature. There are several hypotheses. It is currently believed that our galaxy was formed from a gas cloud consisting of hydrogen. On initial stage During the evolution of the galaxy, the first stars formed from the interstellar gas-dust medium, and 4.6 billion years ago - the Solar System.

Composition of the solar system

The set of celestial bodies moving around the Sun as a central body forms Solar system. It is located almost on the outskirts of the Milky Way galaxy. The solar system is involved in rotation around the center of the galaxy. The speed of its movement is about 220 km/s. This movement occurs in the direction of the constellation Cygnus.

The composition of the Solar System can be represented in the form of a simplified diagram shown in Fig. 3.

Over 99.9% of the mass of matter in the Solar System comes from the Sun and only 0.1% from all its other elements.

Hypothesis of I. Kant (1775) - P. Laplace (1796)	Hypothesis of D. Jeans (early 20th century)	Hypothesis of Academician O.P. Schmidt (40s of the XX century)	Hypothesis akalemic by V. G. Fesenkov (30s of the XX century)
Planets were formed from gas-dust matter (in the form of a hot nebula). Cooling is accompanied by compression and an increase in the speed of rotation of some axis. Rings appeared at the equator of the nebula. The substance of the rings collected into hot bodies and gradually cooled	A larger star once passed by the Sun, and its gravity pulled out a stream of hot matter (prominence) from the Sun. Condensations formed, from which planets were later formed.	The gas and dust cloud revolving around the Sun should have taken on a solid shape as a result of the collision of particles and their movement. The particles combined into condensations. The attraction of smaller particles by condensations should have contributed to the growth of the surrounding matter. The orbits of the condensations should have become almost circular and lying almost in the same plane. Condensations were the embryos of planets, absorbing almost all the matter from the spaces between their orbits	The Sun itself arose from the rotating cloud, and the planets emerged from secondary condensations in this cloud. Further, the Sun greatly decreased and cooled to its present state

Rice. 3. Composition of the Solar System

Sun

Sun- this is a star, a giant hot ball. Its diameter is 109 times the diameter of the Earth, its mass is 330,000 times the mass of the Earth, but its average density is low - only 1.4 times the density of water. The Sun is located at a distance of about 26,000 light years from the center of our galaxy and revolves around it, making one revolution in about 225-250 million years. The orbital speed of the Sun is 217 km/s—so it travels one light year every 1,400 Earth years.

Rice. 4. Chemical composition of the Sun

The pressure on the Sun is 200 billion times higher than at the surface of the Earth. The density of solar matter and pressure quickly increase in depth; the increase in pressure is explained by the weight of all overlying layers. The temperature on the surface of the Sun is 6000 K, and inside it is 13,500,000 K. The characteristic lifetime of a star like the Sun is 10 billion years.

Table 1. General information about the sun

The chemical composition of the Sun is about the same as that of most other stars: about 75% hydrogen, 25% helium and less than 1% all others chemical elements(carbon, oxygen, nitrogen, etc.) (Fig. 4).

The central part of the Sun with a radius of approximately 150,000 km is called the solar core. This is a zone of nuclear reactions. The density of the substance here is approximately 150 times higher than the density of water. The temperature exceeds 10 million K (on the Kelvin scale, in terms of degrees Celsius 1 °C = K - 273.1) (Fig. 5).

Above the core, at distances of about 0.2-0.7 solar radii from its center, is radiant energy transfer zone. Energy transfer here is carried out by absorption and emission of photons by individual layers of particles (see Fig. 5).

Rice. 5. Structure of the Sun

Photon(from Greek phos- light), elementary particle, capable of existing only by moving at the speed of light.

Closer to the surface of the Sun, vortex mixing of the plasma occurs, and energy is transferred to the surface

mainly by the movements of the substance itself. This method of energy transfer is called convection, and the layer of the Sun where it occurs is convective zone. The thickness of this layer is approximately 200,000 km.

Above the convective zone is the solar atmosphere, which constantly fluctuates. Both vertical and horizontal waves with lengths of several thousand kilometers propagate here. Oscillations occur with a period of about five minutes.

The inner layer of the Sun's atmosphere is called photosphere. It consists of light bubbles. This granules. Their sizes are small - 1000-2000 km, and the distance between them is 300-600 km. About a million granules can be observed on the Sun at the same time, each of which exists for several minutes. The granules are surrounded by dark spaces. If the substance rises in the granules, then around them it falls. The granules create a general background against which large-scale formations such as faculae, sunspots, prominences, etc. can be observed.

Sunspots- dark areas on the Sun, the temperature of which is lower than the surrounding space.

Solar torches called bright fields surrounding sunspots.

Prominences(from lat. protubero- swell) - dense condensations of relatively cold (compared to the surrounding temperature) substance that rise and are held above the surface of the Sun by a magnetic field. Towards the emergence magnetic field What may drive the sun is that different layers of the sun rotate at different speeds: the inner parts rotate faster; The core rotates especially quickly.

Prominences, sunspots and faculae are not the only examples of solar activity. It also includes magnetic storms and explosions, which are called flashes.

Above the photosphere is located chromosphere- the outer shell of the Sun. The origin of the name of this part of the solar atmosphere is associated with its reddish color. The thickness of the chromosphere is 10-15 thousand km, and the density of matter is hundreds of thousands of times less than in the photosphere. The temperature in the chromosphere is growing rapidly, reaching tens of thousands of degrees in its upper layers. At the edge of the chromosphere there are observed spicules, representing elongated columns of compacted luminous gas. The temperature of these jets is higher than the temperature of the photosphere. The spicules first rise from the lower chromosphere to 5000-10,000 km, and then fall back, where they fade. All this happens at a speed of about 20,000 m/s. Spi kula lives 5-10 minutes. The number of spicules existing on the Sun at the same time is about a million (Fig. 6).

Rice. 6. The structure of the outer layers of the Sun

Surrounds the chromosphere solar corona- outer layer of the Sun's atmosphere.

The total amount of energy emitted by the Sun is 3.86. 1026 W, and only one two-billionth of this energy is received by the Earth.

Solar radiation includes corpuscular And electromagnetic radiation.Corpuscular fundamental radiation- this is a plasma flow that consists of protons and neutrons, or in other words - solar wind, which reaches near-Earth space and flows around the entire magnetosphere of the Earth. Electromagnetic radiation- This is the radiant energy of the Sun. It reaches in the form of direct and diffuse radiation earth's surface and ensures the thermal regime on our planet.

In the middle of the 19th century. Swiss astronomer Rudolf Wolf(1816-1893) (Fig. 7) calculated a quantitative indicator of solar activity, known throughout the world as the Wolf number. Having processed the observations of sunspots accumulated by the middle of the last century, Wolf was able to establish the average I-year cycle of solar activity. In fact, the time intervals between years of maximum or minimum Wolf numbers range from 7 to 17 years. Simultaneously with the 11-year cycle, a secular, or more precisely 80-90-year, cycle of solar activity occurs. Uncoordinatedly superimposed on each other, they make noticeable changes in the processes taking place in the geographical shell of the Earth.

The close connection of many terrestrial phenomena with solar activity was pointed out back in 1936 by A.L. Chizhevsky (1897-1964) (Fig. 8), who wrote that the overwhelming majority of physical and chemical processes on Earth are the result of the influence of cosmic forces. He was also one of the founders of such science as heliobiology(from Greek helios- sun), studying the influence of the Sun on the living matter of the geographical envelope of the Earth.

Depending on solar activity, such physical phenomena occur on Earth as: magnetic storms, frequency of auroras, amount of ultraviolet radiation, intensity of thunderstorm activity, air temperature, atmospheric pressure, precipitation, levels of lakes, rivers, groundwater, salinity and activity of the seas, etc.

The life of plants and animals is associated with the periodic activity of the Sun (there is a correlation between solar cyclicity and the length of the growing season in plants, the reproduction and migration of birds, rodents, etc.), as well as humans (diseases).

Currently, the relationships between solar and terrestrial processes continue to be studied using artificial Earth satellites.

Terrestrial planets

In addition to the Sun, planets are distinguished as part of the Solar System (Fig. 9).

By size, geographical indicators and chemical composition planets are divided into two groups: terrestrial planets And giant planets. The terrestrial planets include, and. They will be discussed in this subsection.

Rice. 9. Planets of the Solar System

Earth- the third planet from the Sun. A separate subsection will be devoted to it.

Let's summarize. The density of the planet’s substance, and taking into account its size, its mass, depends on the location of the planet in the solar system. How
The closer a planet is to the Sun, the higher its average density of matter. For example, for Mercury it is 5.42 g/cm\ Venus - 5.25, Earth - 5.25, Mars - 3.97 g/cm3.

The general characteristics of the terrestrial planets (Mercury, Venus, Earth, Mars) are primarily: 1) relatively small sizes; 2) high temperatures on the surface and 3) high density of planetary matter. These planets rotate relatively slowly on their axis and have few or no satellites. In the structure of the terrestrial planets, there are four main shells: 1) a dense core; 2) the mantle covering it; 3) bark; 4) light gas-water shell (excluding Mercury). Traces of tectonic activity were found on the surface of these planets.

Giant planets

Now let's get acquainted with the giant planets, which are also part of our solar system. This , .

Giant planets have the following general characteristics: 1) large size and weight; 2) rotate quickly around an axis; 3) have rings and many satellites; 4) the atmosphere consists mainly of hydrogen and helium; 5) in the center they have a hot core of metals and silicates.

They are also distinguished by: 1) low surface temperatures; 2) low density of planetary matter.

What is the solar system in which we live? The answer will be as follows: this is our central star, the Sun and all the cosmic bodies that revolve around it. These are large and small planets, as well as their satellites, comets, asteroids, gases and cosmic dust.

The name of the solar system was given by the name of its star. In a broad sense, “solar” often means any star system.

How did the solar system originate?

According to scientists, the Solar system was formed from a giant interstellar cloud of dust and gases due to gravitational collapse in a separate part of it. As a result, a protostar was formed in the center, which then turned into a star - the Sun, and a protoplanetary disk of enormous size, from which all the components of the Solar system listed above were subsequently formed. The process, scientists believe, began about 4.6 billion years ago. This hypothesis was called the nebular hypothesis. Thanks to Emmanuel Swedenborg, Immanuel Kant and Pierre-Simon Laplace, who proposed it back in the 18th century, it eventually became generally accepted, but over the course of many decades it was refined, new data was introduced into it taking into account knowledge modern sciences. Thus, it is assumed that due to the increase and intensification of collisions of particles with each other, the temperature of the object increased, and after it reached several thousand kelvins, the protostar acquired a glow. When the temperature reached millions of kelvins, a thermonuclear fusion reaction began in the center of the future Sun - the conversion of hydrogen into helium. It turned into a star.

The sun and its features

Scientists classify our star as a yellow dwarf (G2V) according to its spectral classification. This is the closest star to us, its light reaches the surface of the planet in just 8.31 seconds. From Earth, the radiation appears to have a yellow tint, although in reality it is almost white.

The main components of our luminary are helium and hydrogen. In addition, thanks to spectral analysis, it was discovered that the Sun contains iron, neon, chromium, calcium, carbon, magnesium, sulfur, silicon, and nitrogen. Thanks to the thermonuclear reaction continuously occurring in its depths, all life on Earth receives the necessary energy. Sunlight is an integral component of photosynthesis, which produces oxygen. Without sun rays it would be impossible, therefore, an atmosphere suitable for the protein form of life would not be able to form.

Mercury

This is the closest planet to our star. Together with Earth, Venus and Mars, it belongs to the so-called terrestrial planets. Mercury received its name because of its high speed of movement, which, according to myths, distinguished the fleet-footed ancient god. The Mercury year is 88 days.

The planet is small, its radius is only 2439.7, and it is smaller in size than some of the large satellites of the giant planets, Ganymede and Titan. However, unlike them, Mercury is quite heavy (3.3 x 10 23 kg), and its density is only slightly behind that of Earth. This is due to the presence of a heavy dense core of iron on the planet.

There is no change of seasons on the planet. Its desert surface resembles the Moon. It is also covered with craters, but is even less suitable for life. Thus, on the day side of Mercury the temperature reaches +510 °C, and on the night side -210 °C. These are the sharpest changes in the entire solar system. The atmosphere of the planet is very thin and rarefied.

Venus

This planet, named after the ancient Greek goddess of love, is more similar than others in the solar system to the Earth in its physical parameters - mass, density, size, volume. For a long time they were considered twin planets, but over time it became clear that their differences were enormous. So, Venus has no satellites at all. Its atmosphere consists of almost 98% carbon dioxide, and the pressure on the planet’s surface is 92 times higher than Earth’s! Clouds above the surface of the planet, consisting of sulfuric acid vapor, never dissipate, and the temperature here reaches +434 ° C. Acid rain is falling on the planet and thunderstorms are raging. There is high volcanic activity here. Life, as we understand it, cannot exist on Venus; moreover, the descending spacecraft They cannot survive in such an atmosphere for long.

This planet is clearly visible in the night sky. This is the third brightest object for an earthly observer; it shines with white light and is brighter than all the stars. The distance to the Sun is 108 million km. It revolves around the Sun in 224 Earth days, and around its own axis in 243.

Earth and Mars

These are the last planets of the so-called terrestrial group, whose representatives are characterized by the presence of a solid surface. Their structure includes a core, mantle and crust (only Mercury does not have it).

Mars has a mass equal to 10% of the mass of the Earth, which, in turn, is 5.9726 10 24 kg. Its diameter is 6780 km, almost half that of our planet. Mars is the seventh largest planet in the solar system. Unlike the Earth, 71% of whose surface is covered by oceans, Mars is entirely dry land. The water was preserved beneath the planet's surface in the form of a massive ice sheet. Its surface has a reddish tint due to the high content of iron oxide in the form of maghemite.

The atmosphere of Mars is very rarefied, and the pressure on the surface of the planet is 160 times less than what we are used to. On the surface of the planet there are impact craters, volcanoes, depressions, deserts and valleys, and at the poles there are ice caps, just like on Earth.

Martian days are slightly longer than Earth ones, and the year is 668.6 days. Unlike the Earth, which has one moon, the planet has two irregular satellites - Phobos and Deimos. Both of them, like the Moon to the Earth, are constantly turned to Mars with the same side. Phobos is gradually approaching the surface of its planet, moving in a spiral, and will probably fall onto it over time or break into pieces. Deimos, on the contrary, is gradually moving away from Mars and may leave its orbit in the distant future.

Between the orbits of Mars and the next planet, Jupiter, there is an asteroid belt consisting of small celestial bodies.

Jupiter and Saturn

Which planet is the largest? There are four gas giants in the Solar System: Jupiter, Saturn, Uranus and Neptune. Jupiter has the largest size. Its atmosphere, like that of the Sun, consists predominantly of hydrogen. The fifth planet, named after the thunder god, has an average radius of 69,911 km and a mass 318 times that of Earth. The planet's magnetic field is 12 times stronger than the Earth's. Its surface is hidden under opaque clouds. So far, scientists are finding it difficult to say with certainty what processes can occur under this dense veil. It is assumed that there is a boiling hydrogen ocean on the surface of Jupiter. Astronomers consider this planet a “failed star” due to some similarity in their parameters.

Jupiter has 39 satellites, 4 of which - Io, Europa, Ganymede and Callisto - were discovered by Galileo.

Saturn is slightly smaller than Jupiter, it is the second largest among the planets. This is the sixth, next planet, also consisting of hydrogen with admixtures of helium, a small amount of ammonia, methane, and water. Hurricanes rage here, the speed of which can reach 1800 km/h! Saturn's magnetic field is not as powerful as Jupiter's, but stronger than Earth's. Both Jupiter and Saturn are somewhat flattened at the poles due to rotation. Saturn is 95 times heavier than earth, but its density is less than that of water. This is the least dense celestial body in our system.

A year on Saturn lasts 29.4 Earth years, a day is 10 hours 42 minutes. (Jupiter has a year of 11.86 Earth years, a day of 9 hours 56 minutes). It has a system of rings consisting of solid particles of various sizes. Presumably, these may be the remains of a destroyed satellite of the planet. In total, Saturn has 62 satellites.

Uranus and Neptune - the last planets

The seventh planet of the solar system is Uranus. It is 2.9 billion km away from the Sun. Uranus is the third largest among the planets of the Solar System (average radius - 25,362 km) and the fourth largest in mass (14.6 times greater than Earth's). A year here lasts 84 Earth years, a day lasts 17.5 hours. In the atmosphere of this planet, in addition to hydrogen and helium, methane occupies a significant volume. Therefore, for an earthly observer, Uranus has a soft blue color.

Uranus is the coldest planet in the solar system. The temperature of its atmosphere is unique: -224 °C. Scientists do not know why Uranus has a lower temperature than planets that are further from the Sun.

This planet has 27 satellites. Uranus has thin, flat rings.

Neptune, the eighth planet from the Sun, ranks fourth in size (average radius - 24,622 km) and third in mass (17 Earth's). For a gas giant it is relatively small (only four times more than Earth). Its atmosphere is also mainly composed of hydrogen, helium and methane. Gas clouds in its upper layers move at a record speed, the highest in the solar system - 2000 km/h! Some scientists believe that under the surface of the planet, under a layer of frozen gases and water, hidden, in turn, by the atmosphere, a solid rocky core may be hiding.

These two planets are similar in composition, and therefore they are sometimes classified as separate category- ice giants.

Minor planets

Minor planets are celestial bodies that also move around the Sun in their own orbits, but differ from other planets in their small sizes. Previously, only asteroids were classified as such, but more recently, namely since 2006, they also include Pluto, which was previously included in the list of planets of the Solar System and was the last, tenth on it. This is due to changes in terminology. Thus, minor planets now include not only asteroids, but also dwarf planets - Eris, Ceres, Makemake. They were named plutoids after Pluto. The orbits of all known dwarf planets are located beyond the orbit of Neptune, in the so-called Kuiper belt, which is much wider and more massive than the asteroid belt. Although their nature, as scientists believe, is the same: it is “unused” material left after the formation of the Solar system. Some scientists have suggested that the asteroid belt is the debris of the ninth planet, Phaeton, which died as a result of a global catastrophe.

What is known about Pluto is that it is composed primarily of ice and solid rock. The main component of its ice sheet is nitrogen. Its poles are covered with eternal snow.

This is the order of the planets of the solar system, according to modern ideas.

Parade of planets. Types of parades

This is a very interesting phenomenon for those interested in astronomy. It is customary to call a parade of planets such a position in the solar system when some of them, continuously moving in their orbits, for a short time occupy a certain position for an earthly observer, as if lining up along one line.

The visible parade of planets in astronomy is the special position of the five brightest planets of the solar system for people seeing them from Earth - Mercury, Venus, Mars, as well as two giants - Jupiter and Saturn. At this time, the distance between them is relatively small and they are clearly visible in a small sector of the sky.

There are two types of parades. A large form is called when five heavenly bodies line up in one line. Small - when there are only four of them. These phenomena may be visible or invisible from different areas globe. At the same time, a large parade occurs quite rarely - once every few decades. The small one can be observed once every few years, and the so-called mini-parade, in which only three planets participate, almost every year.

Interesting facts about our planetary system

Venus, the only one of all the major planets in the Solar System, rotates around its axis in the direction opposite to its rotation around the Sun.

The highest mountain on the major planets of the Solar System is Olympus (21.2 km, diameter - 540 km), an extinct volcano on Mars. Not long ago, on the largest asteroid of our star system, Vesta, a peak was discovered that was somewhat superior in parameters to Olympus. Perhaps it is the highest in the solar system.

The four Galilean moons of Jupiter are the largest in the Solar System.

In addition to Saturn, all gas giants, some asteroids, and Saturn's moon Rhea have rings.

Which star system is closest to us? The solar system is closest to the star system of the triple star Alpha Centauri (4.36 light years). It is assumed that planets similar to Earth may exist in it.

About planets for kids

How to explain to children what the solar system is? Her model will help here, which you can make together with the kids. To create planets, you can use plasticine or ready-made plastic (rubber) balls, as shown below. At the same time, it is necessary to maintain the relationship between the sizes of the “planets” so that the model of the solar system really helps to form in children the correct ideas about space.

You will also need toothpicks to hold our celestial bodies, and as a background you can use a dark sheet of cardboard with small dots painted on it to imitate stars. With the help of such an interactive toy, it will be easier for children to understand what the solar system is.

The future of the solar system

The article described in detail what the Solar System is. Despite its apparent stability, our Sun, like everything in nature, evolves, but this process, by our standards, is very long. The supply of hydrogen fuel in its depths is huge, but not infinite. So, according to scientists’ hypotheses, it will end in 6.4 billion years. As it burns out, the solar core will become denser and hotter, and the outer shell of the star will become wider. The star's luminosity will also increase. It is assumed that in 3.5 billion years, because of this, the climate on Earth will be similar to Venus, and life on it in the usual sense for us will no longer be possible. There will be no water left at all, under the influence high temperatures it will evaporate into outer space. Subsequently, according to scientists, the Earth will be absorbed by the Sun and dissolve in its depths.

The outlook is not very bright. However, progress does not stand still, and perhaps by that time new technologies will allow humanity to explore other planets, over which other suns shine. After all, scientists do not yet know how many “solar” systems there are in the world. There are probably countless of them, and among them it is quite possible to find one suitable for human habitation. Which “solar” system will become our new home is not so important. Human civilization will be preserved, and another page will begin in its history...