The astronomers had classified the galaxies in the universe according to their shape and appearance. There are different galaxies that exist; Elliptical galaxies, Spiral galaxies and irregular galaxies.
The Elliptical galaxy is considered as the most common type of galaxy. This type of galaxy ranges from a shape of almost spherical shape to a flattened disk shape. Elliptical galaxies which are almost spherical are designated as E0 galaxies. Elliptical galaxies which are less spherical are designated as E3 galaxies. This galaxy varies from small to very large galaxies.
The Spiral galaxies are those which have bulge or nucleus from which there are several arms that may come out. These arms in the Spiral galaxies are composed of dust and stars. Spiral galaxies that have no arms are designated as S0 galaxies. Depending how open the arms are; Spiral galaxies are classified as S2, Sb and Sc. Spiral galaxies classified as SBa, SBb and SBc are those Spiral galaxies that have arms that extend from a bar a bar of stars in the nucleus; they are called as barred spirals. Irregular galaxies are those galaxies that are not elliptical or spiral in shapes.
Galaxies varies from their sizes; there are dwarf galaxies as well as giant galaxies. The smallest galaxy measured about 6600 light-years in diameter while the largest galaxy has a diameter of about 192000 light years in diameter.
There are thousands of galaxies in the whole universe. Some of these galaxies were already observed as well as photographed by the astronomers. Some of them are found to be alone in space and some of them are clustered in groups. The galaxies that belong to the clustered group may contain few galaxies or several thousands of galaxies.
The Solar System is near in the edge of the Milky Way galaxy. The Milky Way consists of about 200 billion of stars including our very own sun. The brightest part of the Milky Way lies in the constellation of Sagittarius. This galaxy passes through the constellation of Cassiopeia and Cygnus in the Northern Hemisphere; while in the Southern Hemisphere it passes through the constellation Scorpio and the Southern Cross.
The Milky Way galaxy belongs to a cluster of galaxies called as the Local Group which has an Elliptical, Spiral as well as Irregular galaxies. The nearest neighbors of the Milky Way in this cluster are the Large and Small Magellanic Clouds; they are Irregular galaxies belongs to the Local Group. The Small Magellanic Cloud is only about 19 light-years in diameter. The Large Magellanic Cloud is about 38400 light-years in diameter and visible with the naked eye from the Southern Hemisphere.
The Common Strategies in Teaching
Steps and Process in the Meta-cognition Teaching
The Experiential Method of Teaching
The Different Stages of Development
The Instruction Theory of Bruner