The galaxy, also called the Milky Way,Consists of a huge number of stars - about 200 billion, but the exact number is still impossible to calculate. Many of them form planetary systems like our solar system.
While scientists have found about a thousand such systems, there are still many discoveries ahead.
The Milky Way is a galaxy in whichThe solar system and the planet Earth. It has the shape of a spiral with a jumper, several arms branch out from the center, and all the stars in the Galaxy revolve around its core. Our Sun is almost on the outskirts and makes a full turn for 200 million years. It forms the planet's most famous planetary system, called the Solar System. It consists of eight planets and many other cosmic objects formed from a gas-dust cloud about four and a half billion years ago. The solar system has been relatively well studied, but stars and other objects beyond its boundaries are at great distances, despite belonging to the same Galaxy.
All the stars that a person can observeWith the naked eye from Earth, are in the Milky Way. Do not confuse the galaxy under this name with the phenomenon that occurs in the night sky: a bright white band crossing the sky. This is part of our Galaxy, a large cluster of stars that looks like this because the Earth is next to its plane of symmetry.
Planetary systems in the Galaxy
Only one planetary system is calledSolar - the one in which the Earth is. But in our Galaxy there are many more systems, only a small part of them is open. Until 1980, the existence of such our systems was only hypothetical: the methods of observation did not allow us to detect such relatively small and faint objects. The first assumption of their existence was made by the astronomer Jacob from the Madras Observatory in 1855. Finally, in 1988, the first planet outside the solar system was found - it belonged to the orange giant Gamma Cepheus A. Then other discoveries followed, it became clear that there could be many. Such planets, not belonging to our system, were called exoplanets.
Astronomers know more than a thousandPlanetary systems, about half of them have more than one exoplanet. But there are still many candidates for this title, while research methods can not confirm this data. Scientists suggest that in our Galaxy there are about a hundred billion exoplanets, which belong to several tens of billions of systems. Perhaps about 35% of all the sunlike stars of the Milky Way are not alone.
Some found planetary systems are completelyDo not look like Sunny, others have more similarities. In some, there are only gas giants (as long as there is more information about them, as they are easier to detect), in others there are planets like Earth.