Solar system. Planets of the solar system
Its center is a huge star called the Sun. It is the closest star that is billions of years gives us light and heat. Without it, impossible would be life on the planet. Around it revolve the planets, of which eight are known today, as well as other celestial objects.
Schematically, the structure of the solar system is as follows:
Man is always interested in the question thus arose our solar system. But it was a long time before scientists were able to answer this question. There were many versions and assumptions on this issue. And today, astronomers are continuing their investigation.
According to a hypothesis of Kant-Laplace five billion years ago there was only a gas cloud. It moved through the universe, but at some point he undergoes certain processes. Then there is compression and then begins the rotation, the center of rotation is the fastest. The temperature at the center of the cloud began to grow and formed a protostar that later became the Sun. The nebula continued to spin, and the star are unable to absorb all the substance of the nebula, they are attracted, experienced, forming planetesimal. One of them appeared on the planet.
Why are the planets so different? This is because due to the high temperaturerise to the star, gas and ice quickly evaporated. Gas giant planets there are unable to form, but there was a concentration of metal particles. Mercury was formed, containing the highest amount of metals. The more removed from the centre, the lower the temperature. Appeared a celestial body in which a large percentage was rock. These four planets, located closer to the center of the system, called internal. Then start the outer planets – the gas giants. The discovery of new systems raises many new issues. The answers will help to get new research.
They have high density and are composed of iron and silicates. Earth is the largest object of the group. All these objects have a similar structure: a core of iron and Nickel, the mantle of silicates, the crust of silicate rocks. Mercury has bark missing, it is assumed that she collapsed due to bombardment by meteorites. Earth and Mars have satellites.