The central star of our system, according to differentThe orbits around which all the planets pass are called the sun. Its age is about 5 billion years. This is a yellow dwarf, so the size of the star is small. Her thermonuclear reactions are not spent very quickly. The solar system has reached about the middle of its life cycle. After 5 billion years, the equilibrium of the forces of gravity will be broken, the star will increase in size, gradually heat up. Thermonuclear fusion converts all the hydrogen of the Sun to helium. At this point, the size of the star will be three times larger. In the end, the star will cool, decrease. Today, the Sun consists almost entirely of hydrogen (90%) and a little of helium (10%).
Today, the sun’s satellites are 8 planets, aroundwhich are converted by other celestial bodies, several dozen comets, as well as a huge number of asteroids. All these objects move in their orbit. If you add up the mass of all the satellites of the Sun, it turns out that they are 1000 times lighter than their star. The main celestial bodies of the system deserve detailed consideration.
General concept of the solar system
To view the satellites of the sun, you needget acquainted with the definitions: what is a star, planet, satellite, etc. A star is a body that radiates light and energy into space. This is possible due to thermonuclear reactions occurring in it and the processes of compression under the influence of gravity. There is only one star in our system - the Sun. Around him turns 8 planets.
Планетой сегодня называется небесное тело, which revolves around a star and has a spherical (or close to it) shape. Such objects do not emit light (they are not a star). They can reflect it. Also, the planet has no other large celestial bodies near its orbit.
Satellite is an object that rotates.around other large stars or planets. It is held in orbit by the force of attraction of this large celestial body. To understand how many satellites the Sun has, it should be noted that this list, in addition to the planets, includes asteroids, comets, meteorites. It is almost impossible to count them.
Planets
Until recently, it was believed that our system has 9 planets. After much deliberation, Pluto was dropped from this list. But it is also part of our system.
8 major planets hold in their orbitsThe sun. The satellite (planet) may also have celestial bodies rotating around it. There are quite large objects. All planets are divided into 2 groups. The first includes the internal satellites of the Sun, and the second - the external.
The planets of the terrestrial (first) group are as follows:
- Mercury (closest to the star).
- Venus (the hottest planet).
- Land.
- Mars (the most accessible object for research).
They consist of metals, silicates, their surface is solid. The outer group is the gas giants. These include:
- Jupiter.
- Saturn.
- Uranus.
- Neptune.
Their composition is characterized by a high content of hydrogen and helium. These are the largest planets in the system.
Satellites of the planets
Considering the question of how many satellites the Sun has,mention should be made of celestial bodies orbiting around the planets. In ancient Greece, the planets were considered to be Venus, Mercury, the Sun, Mars, the Moon, Jupiter, Saturn. Only in the 16th century was Earth listed on this list. The sun has taken in the understanding of people its central importance in our system. The moon turned out to be a satellite of the Earth.
With the advent of more advanced technology has beenfound that almost all the planets have their satellites. Only Venus and Mercury do not possess them. Today, about 60 satellites of planets are known, which are characterized by different magnitudes. The least known of them is Leda. This satellite of Jupiter is only 10 km in diameter.
Most of these objects, located in the orbit of the gas giants, were discovered using automatic space technology. She provided scientists with photographs of such celestial objects.
Mercury and Venus
Два довольно небольших по размеру объекта имеет our star is closest to itself. The satellite of the Sun Mercury is the smallest planet of the system. Venus is somewhat bigger than him. But both of these planets do not have their satellites.
Mercury has a very thin atmosphere.from helium. Around his star, he makes a revolution in 88 Earth days. But the duration of the revolution around its axis on this planet is 58 days (by our standards). The temperature on the sunny side reaches +400 degrees. At night, cooling down to -200 degrees is fixed here.
At Venus, the atmosphere consists of hydrogen withimpurities of nitrogen and oxygen. There is a greenhouse effect. Therefore, the surface is heated to a record +480 degrees. This is more than on Mercury. This planet is best seen from Earth, since its orbit passes closest to us.
Earth
Our planet is the largest among allrepresentatives of the earth group. It is unique in many ways. Earth has the largest celestial body, rotating in its orbit, among the first 4 planets from the star. This is the moon. The satellite of the Sun, which is our planet, is significantly different from all its atmosphere. Thanks to this life became possible on her.
About 71% of the surface is water. The remaining 29% is dry land. The basis of the atmosphere is nitrogen. It also contains oxygen, carbon dioxide, argon and water vapor.
Earth's moon satellite has no atmosphere.It has no wind, no sound, no weather. It is a rocky, bare surface, covered with craters. On Earth, the traces of meteorite impacts are smoothed under the influence of various types of vital activity due to wind and weather. There is nothing on the moon. Therefore, all traces of her past are reflected very clearly.
Mars
This is the terrestrial planet closure group.It is called the "Red Planet" due to the high content of iron oxide in the soil. This is quite Earth-like satellite. Around the Sun, it rotates 678 Earth days. Scientists believed that life could once exist here. However, studies have not confirmed this. The moons of Mars are Phobos and Deimos. They are smaller in size than the moon.
It's colder here than on our planet.At the equator, the temperature reaches 0 degrees. At the poles, it drops to -150 degrees. This world is already available for astronaut flights. A spaceship can reach the planet in 4 years.
В далекие времена по поверхности планеты текли rivers. There was water here. Now there are ice caps at the poles. Only they consist not of water, but of carbon dioxide of the atmosphere. Scientists suggest that water can be frozen in the form of large blocks under the surface of the planet.
Gas giants
Behind Mars are the largest objectswho accompany the sun. The planets (satellites of the planets of this group) were studied using various techniques. The largest object of our system is Jupiter. It is 2.5 times more massive than all the planets taken together, orbiting the sun. It consists of helium, hydrogen (what is similar to our star). The planet radiates heat. However, to be considered a star, Jupiter needs to become 80 times harder. It has 63 satellites.
Saturn is slightly smaller than Jupiter. He is known for his rings. These are ice particles of various diameters. The density of the planet is less than that of water. It has 62 satellites.
Uranus and Neptune are located further away than twoprevious planets. They were discovered with a telescope. They contain a large number of high-temperature modifications of ice. This is the "Ice Giants." Uranus has 23 satellites, and Neptune has 13.
Pluto
Спутники солнца дополняются также небольшим object called Pluto. From 1930 to 2006, he had the title of the planet. However, after lengthy discussions, scientists came to the conclusion that this is not a planet. Pluto falls into another category. From the point of view of the current planetary classification, it is a prototype of dwarf planets. The surface of the object is covered with frozen ice of methane and nitrogen. Pluto has 1 satellite.
Having studied the main satellites of the Sun, it should be saidthat this is a whole system consisting of a large number of different objects. Their characteristics, indicators are different. All these objects are united by a force that forces them to constantly rotate around their central star.
