The star system of the Milky Way galaxy, in which we live, 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? Why are they so interesting for science?
What is a satellite?
A satellite is a small body that rotates around the planet under the influence of gravity. We currently know of 44 such celestial bodies.
Satellites are absent only from the first two planets of our star system, Venus and Mercury. The earth has one satellite (the moon). The "Red Planet" (Mars) has 2 celestial bodies accompanying it - Deimos and Phobos. Jupiter, the largest planet in our solar system, has 16 moons. Saturn has 17, Uranus has 5, and Neptune has 2.
Types of satellites
All satellites are divided into 2 types - natural and artificial.
Artificial –man-made celestial bodies that open up the possibility of observing and exploring the planet, as well as other astronomical objects. They are necessary for mapping, weather forecasting, radio broadcasting of signals. The largest man-made "fellow traveler" of the Earth is the International Space Station (ISS). Artificial satellites are not only around 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 has always aroused the genuine interest of scientists. There are several theories, but let's focus on the official versions.
Around every planet there is an accumulation of cosmic 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 are separated from space bodies colliding with the planet, which subsequently acquire a spherical shape. According to this assumption, the natural satellite of the Earth is a fragment of our planet. This is also confirmed by the similarity of the terrestrial and lunar chemical compositions.
Satellite orbits
There are 3 types of orbits.
The polar is inclined to the equatorial plane of the planet at a right angle.
The trajectory of the inclined orbit is shifted relative to the equatorial plane by an angle of less than 900.
Equatorial (also called geostationary) is located in the same plane, along its trajectory a celestial body moves at the speed of the planet's rotation around its axis.
Also, the orbits of satellites are divided into two basic types according to their shape - circular and elliptical. In a circular orbit, a 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 changes within the period of one revolution.
Natural satellites of the planets of the solar system: interesting facts
Saturn's moon Titan has its own dense atmosphere. On its surface there are lakes, which include liquid hydrocarbon compounds.
Europe (moon of Jupiter) is covered with ice, under which there is supposedly an ocean. Scientists also hypothesized that there are active geothermal sources inside this ocean.
Another satellite of Jupiter - Io - aroused special interest of astrophysicists. Active volcanoes have been discovered on it.
Artificial Earth satellites (AES)
According to the generally accepted definition, a satellite is an aircraft that has made at least one revolution around the Earth. The first artificial satellites were launched into near-Earth orbit by the Soviet Union (1957) and the USA (1958). Thanks to this, the density of the upper layers of the atmosphere was measured, and the features of the propagation of radio signals were studied. This was truly a 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), China (1970) and Great Britain (1971).
Space research is based on international scientific and technical cooperation. For example, countries friendly to the USSR carried out satellite launches from Soviet cosmodromes. Some satellites made in Canada, France, Italy have been launched since 1962 using US-designed launch vehicles.
What is a satellite? This is a cosmic body rotating in orbit around a particular planet. By origin, they are natural and artificial. The natural satellites of the planets are of particular interest to the world community, because they still hold many mysteries in themselves, and most of them are still waiting to be discovered. There are projects for their study of private, state and world significance. Artificial satellites make it possible to solve applied and scientific problems both on the scale of a single planet and the entire outer space.
