The Milky way

                        The Milky Way

Our Galaxy which includes the Solar System is called the Milky Way. The Milky Way consists of about 150 billion stars. It is spiral shaped with a bulge at the centre. Four arms surround the central bulge spirally outwards and a less dense halo borders the Milky way. The central bulge contains red and yellow stars. The spiral arms contain clouds of dust and gas in which hot, young, blue stars are seen. The four spiral arms are the Orion arm, Sagittarius arm, Perseus arm and Crux-Centaurus arm. The Solar System is in the Orion arm. It is at a distance of 25,000 light years from the centre of the Milky Way. The Milky Way is about 1,00,000 light years across and 5,000 light years thick. The Milky Way is rotating in space. The speed of movement of the outer stars are low when compared to the inner stars. The nearest Galaxy to the Milky Way is Andromeda.