The Galaxy
Galactic Mergers
Galaxy mergers can occur when two or more galaxies collide. They are the most violent type of galaxy interaction.
Spiral Galaxy
A galaxy in which the stars and gas clouds are concentrated mainly in one or more spiral arms.
Elliptical Galaxy
An elliptical galaxy is a type of galaxy having an approximately ellipsoidal shape and a smooth, nearly featureless brightness profile. Unlike flat spiral galaxies with organization and structure, they are more three-dimensional, without much structure, and their stars are in somewhat random orbits around the center.
Irregular Galaxy
Some irregular galaxies are the result of gravitational interactions or collisions between formerly regular galaxies. Many irregular galaxies orbit larger regular ones; the Magellanic Cloud galaxies orbiting the Milky Way are examples. Compare elliptical galaxy, lenticular galaxy, spiral galaxy.
