No one really knows how various galaxies were formed and how was the universe created. But we do have some rough information about the origin of spiral galaxies. In early 20th century astronomy, Edwin Hubble formed an idea about the expansion of universe. People have estimated the approximate age of the universe based on its rate of expansion. Some existing galaxies are a billion light years away from us, which means that they are the oldest. In 1962, astronomers Olin Eggen, Donald Lynden-Bell and Alln Sandage suggested that spiral galaxies form due to the collapsing of large gas clouds. When the cloud falls it settles and the erupting gas takes a form of a rotating disk. This theory was very popular at some point, but is no longer accepted. Spiral galaxies are quite fragile and thin so they merge with other galaxies very easily, this merger makes it more difficult to understand their formation. As spiral galaxies continue their joining streak they gather more and more mass which makes them thin. This thinness causes the expansion of gas in the galaxy to contract thus making it extremely thinner. Astronomers still don’t have a definite answer on the formation and merger of galaxies, however, in recent years a great amount of research has been done to understand this concept. Galaxies travel the universe and collide with each other, sometimes this collision destroys them and sometimes they merge and become a bigger galaxy.
Posted on: Wed, 10 Sep 2014 12:01:41 +0000
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