In an everyday spiral galaxy (ho hum?), every effort is made by the galaxy itself to minimize the amount of energy wasted on forming turbulence of dust and hydrogen. As a result, areas of intense star formation in a regular spiral is usually restricted to a discrete points along the spiral arms where ISM and molecular cloud rub against each other to create the turbulence. These limited areas of star formation are seen as patches of bright red Halpha emissions. In this image of the Cigar Galaxy, it is evident that something has thrown “a wrench/spanner into the works” and created a hell of lot of turbulence, resulting in a fireworks display of red Halpha. When this occurs, stars are created at a very high rate and we reclassify such galaxies as “starburst” glaxies and the Cigar is one of them. Still, the original stars and dust lanes of this once regular spiral can be made out.
Stars are born – Have a Cigar
