The central star of our system, in different orbits around which all planets pass, is called the Sun. His age is about 5 billion years. This is a yellow dwarf, so the size of the star is small. Its thermonuclear reactions are not consumed very quickly. The solar system has reached approximately the middle of its life cycle. After 5 billion years, the balance of gravity will be disrupted, the star will increase in size, gradually warm up. Thermonuclear fusion converts all of the hydrogen in the sun into 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 satellites of the Sun are 8 planets around which other celestial bodies revolve, dozens of 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 consider the satellites of the Sun, you need to familiarize yourself with the definitions: what is a star, planet, satellite, etc. A star is a body that emits light and energy into space. This is possible due to the thermonuclear reactions occurring in it and compression processes under the influence of gravity. There is only one star in our system - the Sun. Around him are 8 planets.
A planet today is a celestial body that revolves around a star and has a spherical (or close to it) shape. Such objects do not emit light (not a star). They can reflect it. Also, the planet does not have other large celestial bodies near its orbit.
A satellite is an object that revolves around other large stars or planets. It is held in orbit by the force of gravity of this large celestial body. To understand how many satellites the sun has, it should be noted that this list, in addition to planets, includes asteroids, comets, meteorites. Recounting them is almost impossible.
Planets
Until recently, it was believed that our system has 9 planets. After much discussion, Pluto was excluded from this list. But it is also part of our system.
The 8 major planets are held by the Sun in their orbits. A satellite (planet) can also have celestial bodies orbiting 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 - external.
The planets of the earth (first) group are as follows:
- Mercury (closest to the star).
- Venus (the hottest planet).
- Earth.
- Mars (the most accessible object for research).
They are composed 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, it is worth mentioning celestial bodies orbiting planets. In ancient Greece, the planets were Venus, Mercury, the Sun, Mars, the Moon, Jupiter, Saturn. Only in the 16th century the Earth was included in 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 technologies, it was found that almost all planets have their own satellites. Only Venus and Mercury do not possess them. Today, about 60 planet satellites are known, which are characterized by different sizes. 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
Two rather small in size objects is our star closest to itself. The satellite of the Sun Mercury is the smallest planet in the system. Venus is slightly larger than him. But both of these planets do not have their moons.
Mercury has a very rarefied atmosphere of helium. Around his star, he makes a revolution in 88 Earth days. But the duration of the revolution around its axis at this planet is 58 days (by our standards). The temperature on the sunny side reaches +400 degrees. At night, cooling to -200 degrees is recorded here.
In Venus, the atmosphere consists of hydrogen with impurities of nitrogen and oxygen. There is a greenhouse effect. Therefore, the surface heats up to a record +480 degrees. This is more than on Mercury. This planet is best seen from Earth, as its orbit passes closest to us.
Earth
Our planet is the largest among all representatives of the earth group. It is unique in many ways. The 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 has become possible on her.
About 71% of the surface is water. The remaining 29% is land. The atmosphere is based on nitrogen. It also includes oxygen, carbon dioxide, argon and water vapor.
Earth satellite The moon has no atmosphere. There is no wind, sounds, weather. It is a rocky, bare surface covered with craters. On Earth, traces of impacts of meteorites are smoothed out under the influence of various types of life, thanks to the wind and weather. There is nothing on the moon. Therefore, all traces of her past are reflected very clearly.
Mars
This is the closing planet of the earth group. It is called the "Red Planet" due to the high content of iron oxide in the soil. This is a pretty Earth-like satellite. Around the Sun, it revolves 678 Earth days. Scientists believed that life could once exist here. However, studies have not confirmed this. Companions of Mars are Phobos and Deimos. They are smaller than the moon.
It is 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.
In ancient times, rivers flowed on the surface of the planet. There was water. There are ice caps at the poles. Only they do not consist of water, but of carbon dioxide in the atmosphere. Scientists suggest that water can be frozen in the form of large blocks below the surface of the planet.
Gas giants
Beyond Mars are the largest objects that accompany the Sun. 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 combined around the sun. It consists of helium, hydrogen (which is similar to our star). The planet radiates heat. However, to be considered a star, Jupiter needs to become 80 times heavier. 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 even further than the two previous planets. They were discovered using a telescope. They contain a large number of high-temperature modifications of ice. This is Ice Giants. Uranus has 23 satellites, and Neptune has 13.
Pluto
Satellites of the sun are also complemented by a small object called Pluto. From 1930 to 2006, he possessed the title of 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, this 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 said that this is a whole system consisting of a large number of different objects. Their characteristics, indicators are different. A force unites all these objects, forcing them to constantly rotate around their central star.