Star system of the Milky Way galaxy, inwhich we live in includes the Sun and 8 other planets revolving around it. First of all, scientists are interested in studying the planets closest to the Earth. However, the satellites of the planets are also very interesting. What is a satellite? What are their types? What are they so interesting for science?
A companion is a small body that makes rotational movements around the planet under the influence of gravity. At present, we know 44 such celestial bodies.
Satellites are absent only in the first two planetsour star system, Venus and Mercury. The earth has one companion (the Moon). The "Red Planet" (Mars) has 2 celestial bodies accompanying it - Deimos and Phobos. The largest planet of our star system - Jupiter - has 16 satellites. Saturn has 17, Uranus has 5, and Neptune has 2.
All satellites are divided into 2 types - natural and artificial.
Artificial - people created by heavenly bodies,which provide an opportunity to observe and explore the planet, as well as other astronomical objects. They are necessary for mapping, weather forecasting, radio signal transmission. The largest man-made "companion" of the Earth is the International Space Station (ISS). Artificial satellites are not only on our planet. Over 10 such celestial bodies revolve around Venus and Mars.
What is a natural satellite? They are created by nature itself. Their origin always aroused the genuine interest of scientists. There are several theories, but we will dwell on official versions.
Near each planet there is a clustercosmic dust and gases. The planet attracts celestial bodies that fly close to it. As a result of this interaction, satellites are formed. There is also a theory according to which fragments from the cosmic bodies colliding with the planet are separated, which subsequently acquire a spherical shape. According to this assumption, the natural satellite of the Earth is also a fragment of our planet. This is confirmed by the similarity of the terrestrial and lunar chemical compositions.
There are 3 types of orbits.
The polar is inclined to the equatorial plane of the planet at right angles.
The trajectory of the inclined orbit is displaced in relation to the equatorial plane by an angle less than 900.
Equatorial (also called geostationary) is located in the same name plane, along its trajectory the celestial body moves with the speed of revolution of the planet around its axis.
Also the orbits of satellites in their formare divided into two basic types - circular and elliptical. In a circular orbit, the celestial body moves in one of the planes of the planet with a constant distance above the surface of the planet. If the satellite moves in an elliptical orbit, this distance varies within the period of one revolution.
Saturn's satellite Titan has its own dense atmosphere. On its surface there are lakes, which include liquid hydrocarbon compounds.
Europe (the satellite of Jupiter) is covered with ice, under which the ocean is presumably located. Also scientists have put forward a hypothesis that there are operating geothermal sources inside this ocean.
Another companion of Jupiter - Io - aroused special interest of astrophysicists. On it, active volcanoes are found.
According to the generally accepted definition, an artificial earth satellitecalled an aircraft, which at least once made a revolution around the Earth. The first artificial satellites were launched into the near-earth orbit by the Soviet Union (1957) and the USA (1958). Due to this, the density of the upper layers of the atmosphere was measured, and the features of the propagation of radio signals were investigated. This has become a real breakthrough in space exploration and the beginning of the Space Age.
Following the USSR and the United States, satellites were launched by France (1965), Australia (1967), Japan (1970), PRC (1970) and Great Britain (1971).
The conduct of space research is based oninternational scientific and technical cooperation. So, for example, friendly countries of the USSR carried out satellite launches from Soviet cosmodromes. Some satellites manufactured in Canada, France, Italy, since 1962 were launched using US launch vehicles.
What is a satellite?It is a cosmic body rotating orbit around a planet. By origin they are natural and artificial. The special interest of the world community is caused by natural satellites of the planets, because they still have many mysteries in themselves, and most of them are still waiting for discovery. There are projects on their study of private, state and world significance. Artificial satellites allow us to solve applied and scientific problems both on the scale of a single planet and the whole of outer space.
