Our galaxy

Our galaxy is a spiral galaxy the Milky Way. Our galaxy contains billions of stars in the shape of a pancake (the galactic disk), which has spiral sleeves (or branches). The shape of the sleeve can be compared with the water jets emitted from the rotating system for watering lawns. They have a lot of bright, young, blue stars and gas clouds. The spiral sleeves of the galactic disk dotted with groups of young hot stars (called associations); also there are many bright and dark nebulae.

Our galaxy is a spiral galaxy the Milky Way

Our galaxy is probably almost as old as the universe. It is, certainly, more than 12 billion years. Scientists estimate that such is the age of some of its stars, according to other estimates, some stars even older. Alas, none of those we know, was not a witness to how our galaxy was born. At that time, even the Earth did not yet exist, so the estimates are very approximate.

Our galaxy has a shape and dimensions which are caused by the existing laws of gravity in the Universe. A long time ago under the influence of gravity giant cloud of primordial gas gathered together and began to squeeze. When small clots inside the cloud shrank even faster than all the cloud as a whole, the stars were formed. Big cloud starts to rotate very slowly, but its rotation accelerates, there is a flattening of its shape and turns in the spiral disk.

It is necessary to say a few words about the history of the discovery of our Galaxy. Herschel realized that all the stars we observe form a gigantic star system, which is flattened to the galactic equator. Initially, it was assumed that all objects of the universe are parts of our galaxy. Kant has suggested that some of the nebula can be galaxies, like the Milky Way. More in 1920 the question of the existence of extragalactic objects caused debate. Kant's hypothesis was finally proved only in 1920 when Edwin Hubble was able to measure the distance to some spiral nebulae and show that they can not be part of our galaxy.

Possible collision of our galaxy with other galaxies, including with such large as the Andromeda Galaxy, but the specific prediction is not possible because of lack of knowledge of the transverse velocity of extragalactic objects. According to published data, according to one of the models through 4 billion years the Milky Way "absorb" the Large and Small Magellanic Clouds, and in 5 billion years, he will be absorbed by Andromeda.