Peering into the night sky, we can see a broad band, completely studded with stars: bright and barely visible, white and blue, red and green. A cluster of stars ancient Greeks called Galaxy, which in Russian means the milky Way.
The milky Way in the night sky
If you look at this star system somewhere from world space, then you would notice that it resembles a flattened ball, filled with 150 billions of stars. The size of our Galaxy is so large that it is difficult to imagine. From one side to the other light beam travels about 100 thousand earth years!
Looks like our Galaxy
In the center of our Galaxy is the core from which departs a few huge spiral branches, filled with stars. Our Sun is located at a distance 30 thousand light years from the Galactic centre, in one of its spiral arms. That is, it is located on the outskirts of the Galaxy.
The position of the Sun in the Galaxy
The stars in the Galaxy, despite the apparent "density"are quite rare. For example, in the vicinity of the Sun, the average distance between the nearest star is about 10 million times greater than their own diameter.
Thus, the stars in the Universe are not scattered randomly. They are grouped into an ordered system, which are connected to each other by gravity (gravity). Such star systems called galaxies. In addition to the stars, the galaxies is interstellar dust and gas.
In the Universe there are other galaxies. The closest to our star system far from us at a distance of about 150 thousand light years. In the sky of the southern hemisphere they are seen as little foggy spots.
Galaxies in the Universe
For the first time these star clusters have been described in detail, the companion of Magellan by Pigafetta during the famous voyage around the world. They went in astronomy called the Magellanic Clouds - Big and Small.
One of the closest neighbouring galaxies, the Andromeda Nebula. She is one of the biggest stellar systems in our region of the Universe. It can be observed even in ordinary binoculars, and if the weather is good and the naked eye.
Galaxies have a variety of form and structure. Distinguish between spherical and elliptical, in the form of a disc, a spiral, like ours, and galaxies irregular shape.
Types of galaxies
In the part of the Universe accessible to modern means of astronomical research, there are billions of galaxies. Their combination astronomers have named Metagalactic.