Солнечная система

Solar system

A planetary system that includes a central star - the Sun - and all natural cosmic objects revolving around the Sun. It was formed by gravitational compression of a gas-dust cloud about 4.57 billion years ago .

Terminology

All objects of the solar system that revolve around the Sun are officially divided into three categories: planets, dwarf planets and small bodies of the solar system. The planet is any body in orbit around the Sun that turned out to be massive enough to acquire a spherical shape, but not massive enough to start thermonuclear fusion, and was able to clear the vicinity of its orbit from planetesimals. According to this definition, there are eight known planets in the Solar System: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Pluto does not comply with this definition, because it has not cleared its orbit from the surrounding objects of the Kuiper belt. A dwarf planet is a celestial body that orbits the Sun; which is massive enough to maintain close to a round shape under the influence of its own forces of gravity; but which has not cleared the space of its orbit from the planetesimals and is not a satellite of the planet. By this definition, the Solar System has five recognized dwarf planets: Ceres, Pluto, Haumea, Makemake and Eris. In the future, other objects can be classified as dwarf planets, for example, Sedna, Orc and Kvavar. Dwarf planets whose orbits are in the region of trans-Neptunian objects are called plutoids. The remaining objects revolving around the Sun are the small bodies of the Solar System.

Composition

• The sun
• Mercury
• Venus
• The Earth
• Moon
• Mars
• Jupiter
• Saturn
• Uranium
• Neptune

Composition

1.The sun

2. Mercury

3. Venus

4. The Earth

5.Moon

6. Mars

7. Jupiter

8. Saturn

9. Uranium

10. Neptune

The sun

The sun is the star of the solar system and its main component. Its mass (332,900 Earth masses) is large enough to support a thermonuclear reaction in its interior, in which a large amount of energy is emitted into the space mainly in the form of electromagnetic radiation, the maximum of which falls within the range of 400- 700 nm, corresponding to visible light.

According to the star classification, the Sun is a typical yellow dwarf of class G2. This name can be misleading, since compared to most stars in our Galaxy, the Sun is a fairly large and bright star. The star's class is determined by its position on the Hertzsprung-Russell diagram, which shows the relationship between the brightness of stars and the temperature of their surface. Usually the hotter stars are brighter. Most of the stars are on the so-called main sequence of this diagram, the Sun is located approximately in the middle of this sequence. Brighter and hotter than the Sun, stars are relatively rare, and more dull and cool stars (red dwarfs) occur frequently, accounting for 85% of stars in the Galaxy.

Mercury

Mercury (0.4 AU from the Sun) is the nearest planet to the Sun and the planet's smallest planet (0.055 Earth masses). The planet does not have satellites. Characteristic details of the relief of its surface, in addition to impact craters, are numerous lobate-shaped ledges extending for hundreds of kilometers. It is believed that they arose as a result of tidal deformations at an early stage of the history of the planet at a time when Mercury's revolution around the axis and around the sun did not go into resonance. Mercury has an extremely rarefied atmosphere, it consists of atoms "knocked out" from the surface of the planet by the solar wind. The relatively large iron core of Mercury and its thin crust have not yet been satisfactorily explained. There is a hypothesis suggesting that the outer layers of the planet, consisting of light elements, were disrupted as a result of a giant collision, as a result of which the dimensions of the planet decreased. Alternatively, the radiation of a young Sun could interfere with the complete accretion of matter.

Venus

Venus is close in size to the Earth (0.815 Earth mass) and, like Earth, has a thick silicate shell around the iron core and atmosphere (because of this, Venus is often called the "sister" of the Earth). There is also evidence of its internal geological activity. However, the amount of water on Venus is much less than the terrestrial, and its atmosphere is ninety times denser. Venus does not have satellites. This is the hottest planet in our system, its surface temperature exceeds 400 ° C. The most likely cause of such a high temperature is the greenhouse effect, which arises from a dense atmosphere rich in carbon dioxide. There are no obvious signs of modern geological activity on Venus, but since it does not have a magnetic field that would prevent the depletion of its dense atmosphere, it allows us to assume that its atmosphere is regularly replenished with volcanic eruptions.

The Earth

The earth is the largest and densest of the terrestrial planets. Earth tectonics of plates is observed. The question of the existence of life anywhere, except the Earth, remains open. Among the terrestrial planets, the Earth is unique (primarily due to the hydrosphere). The Earth's atmosphere radically differs from the atmospheres of other planets - it contains free oxygen. The Earth has one natural satellite - the Moon, the only large satellite of the planets of the terrestrial group of the solar system.

Moon

The moon is a natural satellite of the Earth. The planet's closest satellite to the Sun, since there are no satellites near the planets, Mercury and Venus closest to the Sun. The second in brightness an object on the earth's firmament after the Sun and the fifth largest natural satellite of the planet of the solar system. The average distance between the centers of the Earth and the Moon is 384,467 km (0.002 57 AU, ~ 30 diameters of the Earth).

Mars

Mars is smaller than the Earth and Venus (0.107 Earth masses). It has an atmosphere consisting mainly of carbon dioxide, with a surface pressure of 6.1 mbar (0.6% of the earth's). On its surface there are volcanoes, the largest of which, Olympus, exceeds the dimensions of all terrestrial volcanoes, reaching an altitude of 21.2 km. The rift basins (the Mariner Valley), along with the volcanoes, testify to the former geological activity, which, according to some data, continued even during the last 2 million years. The red color of the surface of Mars is caused by a large amount of iron oxide in its soil. The planet has two moons - Phobos and Deimos. It is assumed that they are captured by asteroids. To date (after the Earth), Mars is the most thoroughly studied planet in the solar system.

Jupiter

Jupiter has a mass of 318 times more terrestrial, and 2.5 times more massive than all other planets combined. It consists mainly of hydrogen and helium. The high internal temperature of Jupiter causes a number of semi-permanent vortex structures in its atmosphere, such as cloud bands and the Great red spot.

Jupiter has 67 satellites. The four largest - Ganymede, Callisto, Io and Europe - are similar to the terrestrial planets with phenomena such as volcanic activity and internal heating. Ganymede, the largest satellite in the solar system, is larger than Mercury.

Saturn

Saturn, known for its extensive system of rings, has a somewhat similar structure to Jupiter's atmosphere and magnetosphere. Although the volume of Saturn is 60% Jovian, the mass (95 Earth masses) is less than a third of the Jovian; Thus, Saturn is the least dense planet of the solar system (its average density is less than the density of water).

Saturn has 62 confirmed satellites; two of them - Titan and Enceladus - show signs of geological activity. This activity, however, is not similar to the terrestrial, since it is largely due to the activity of ice. Titan, surpassing the dimensions of Mercury, is the only satellite in the solar system with a significant atmosphere.

Uranium

Uranium with a mass of 14 times greater than that of the Earth, is the lightest of the giant planets. Unique among other planets is that it rotates "lying on its side": the inclination of the axis of its rotation to the plane of the ecliptic is approximately 98 °. If other planets can be compared to spinning tops, then Uranus is more like a rolling ball. It has a much colder core than other gas giants, and emits very little heat into space.

Uranus has 27 satellites; the largest - Titania, Oberon, Umbriel, Ariel and Miranda.

Neptune

Neptune, although slightly smaller than Uranus, is more massive (17 Earth masses) and therefore more dense. It emits more internal heat, but not as much as Jupiter or Saturn.

Neptune has 14 known satellites. The largest - Triton, is geologically active, with geysers of liquid nitrogen. Triton is the only major satellite moving in the opposite direction.