Formation of planets - the difficult, chaotic, up to the end not studied process. As scientists cannot observe formation of planets in reality, they should build only theories and to model the corresponding processes. Planets are the most difficult types of celestial bodies, on modern scientific representations only on them life can arise.
Instruction
1. There is a big variety of the planets differing by the sizes, structure, weight therefore it is impossible to speak about any uniform way of formation of planets. Unique features of each star system are connected with features of its formation.
2. There are two main theories about emergence of planets. The first assumes education in a protoplanetary cloud of the centers of masses around which dust and gases from a cloud begins to gather. This theory is called the theory of accretion and is at the moment standard. Other theory - gravitational instability - assumes that planets are formed as a result of sudden collapse of unstable parts of a protoplanetary cloud. This theory has a number of serious shortcomings.
3. Around each new star the huge gas-and-dust cloud which under the influence of gravitational forces begins to rotate quicker and quicker around a star is formed and to contract.
4. Approximately through 1 million years after emergence of a star the gas-and-dust cloud is divided into two parts, in one, closer to a star, heavier particles, in another, more remote accumulate, generally there is a gas. In the solar system these areas are divided between orbits of Mars and Jupiter, that is in one zone firm planets, and in another - gas giants are formed.
5. In a gas-and-dust cloud as a result of accretion, that is falling and sticking of small particles to larger, there is a set planetezimaly, small objects which attract to themselves increasing number of substance. The more they become, the their weight begins to grow quicker. Sometimes they face among themselves and form even more massive objects. During several million years around a star there are active rough processes of collision, destruction and education planetezimaly which fight for the substance which remained in a cloud. Germs of planets result.
6. Stabilization of process is influenced by emergence of large gas giants which begin to influence the attraction smaller germs, to stabilize their orbits. Some more tens of millions of years a system stabilize, germs of planets grow and the new stable planetary system is as a result formed.