A spiral galaxy is shaped like a disk with a bulge in the center. The disk resembles a pinwheel, with bright spiral arms that coil out from the central bulge. The Milky Way is a spiral galaxy. Elliptical galaxies range in shape from almost perfect spheres to flattened globes. The light from an elliptical galaxy is brightest in the center and gradually becomes fainter toward its outer region.
Irregular galaxies have no particular shape.
Star Clusters Star clusters may be either ball-like or of irregular shapes. Ball-like clusters, called globular clusters, contain from 10,000 to a million stars densely packed together. About 100 globular clusters lie around the center of the Milky Way. The stars in globular clusters are among the oldest in our galaxy. Irregularly shaped clusters, called open clusters or galactic clusters, have from less than a hundred to a few thousand stars.