Much like humans, galaxies are shaped by the environment in which they form. While no two are exactly alike, they can be divided into three main types: spiral, elliptical and irregular. Of these types, elliptical galaxies are the largest and are thought to evolve out of galactic collisions and mergers between spirals. About one-tenth of elliptical galaxies are classified as shell galaxies, characterized by the concentric shells that make up their galactic haloes.
Click here for original story, DECam captures the stunning layers of shell galaxy NGC 3923 and nearby gravitational lensing
Source: Phys.org