Those who like to look at the night sky, may have noticed a broad band tightly strewn variety of (bright, barely perceptible, blue, white, etc.) stars.This cluster is the galaxy.
What is a galaxy?One of the greatest mysteries of the universe is that countless stars are not scattered randomly in space and is grouped into galaxies.Almost in the same way as people populate the city, leaving a space between the settlements empty.
Our planet is part of the Milky Way galaxy.Some names of galaxies are well known: the Large and Small Magellanic Clouds, Andromeda.These we can look to the naked eye, others are very distant from Earth. quite a long time could not see individual stars in them, it turned out to make only in the 20th century.
"What is a galaxy?"- This question has long interested scientists.But the real breakthrough in this area occurred in the late twentieth century, when it was created and launched into space telescope "Hubble".
size of our galaxy is so vast that it is impossible to even imagine.One hundred thousand Earth years need beam of light to get it from one end to the other.In its center is located the core from which several branches spiraling lines filled with stars."Density" the only apparent, in fact they are located quite rare.
There are different types of galaxies.They differ in shape, weight, size, as well as the substances contained.They all contain gas and stardust.There are spiral, elliptical, irregular, sphere-like other forms of galaxies.
What is a galaxy?What is their age?How do they work?What processes are in place?Their age is approximately equal to the age of the universe.For the scientists it is still a mystery, what is the core of the galaxy.It has been found that some nuclei are quite active.It was a surprise, because until this discovery, it was thought that the nucleus is a dense cluster of hundreds of millions of stars.The radiation (optical and radio) may vary in some galactic nuclei in a few months.This means that they release huge amounts of energy (much more than in a supernova explosion) in a short time.
in 1963 revealed a completely new objects that have the look of their star called quasars.The luminosity of them, as it turned out, far superior luminosity galaxies.Surprisingly, the brightness of the quasar may vary.
Formation of galaxies - it is a natural process of evolution of the universe flowing under gravity.The variety of types and shapes of galaxies is due to a variety of conditions in which they were born.Compression galaxy can last 3 billion. Years.At this time, the transformation of the gas in the star system.It is by compression of the gas clouds and star formation (when a certain density and temperature sufficient for fusion processes).
Gradually interstellar gas reserves are being depleted, and the formation of stars becomes less intense.When all resources are exhausted, a spiral galaxy is transformed into lenticular, consisting entirely of red stars.This stage are elliptical galaxies, whose gas resources were spent another 15-20 billion. Years ago.
Many people have an idea of what a galaxy is formed of numerous fantastic films, the characters who love to travel the expanses of space, to visit unknown planets and galaxies.In fact, this in the foreseeable future is not planned.Even if we move at the speed of light (which is also impossible), then to the Andromeda Galaxy (our nearest galaxy) we get only after 2.5 million years.Although (according to the calculations of astronomers) it is close to us and in 4-5 billion years, faced with our Milky Way, which will lead to the formation of a new elliptical galaxy.
