basic cosmology

coming to the point of galaxies, these are formed because of thethe exploitation itself, where the first outshred material in the expamsion of universe or formation of universeare these galaxies.these galaxies have more eminent and prominrnt role for the further discussion for the study of universe.these galaxies also plays a vital role to describe the cosmology of universe.
in this universe matter converting to energy and energy converting into matter takes place completely and continuously.,this is what we call in our general life as "Law of conservation of Energy"It's not to say that these takes place only on the law of conservation of Energy, but there are many principles reason for exploision of homogenius and heterogenius particle to form these galaxies with different conservative law.On the basis of above principle there developed a gravitational field in every planet induvidually and a constant force developed between earth, sun and other celestial objects in the system and space.the classicla defination off galaxies says that "Galaxies are large systems of stars and interstellar matter, typically containing several million to some trillion stars, of masses between several million and several trillion times that of our Sun, of an extension of a few thousands to several 100,000s light years, typically separated by millions of light years distance"
we will discuss further the classification of galaxies in detail in the further forum