What is an Elliptical Galaxy?
Unlike the defined disks and spiraling arms of spiral galaxies, an Elliptical galaxy is one without very much structure. Having a rather bland appearance, elliptical galaxies (hence the name) take on a featureless ellipsoidal shape. This type of galaxy is the most abundant in the universe and can vary greatly in size, some dwarf elliptical galaxies can get as small as 10% the size of the Milky Way, while others such as M87 are identified as some of the largest galaxies in the universe with over ten trillion stars! Most ellipticals are composed of very old stars with a very thin interstellar medium leading to little or no star formation. The formation of these galaxies is in almost all cases thought to be the result of galactic collisions in where two or more galaxies collide and merge to form one with less structure.