Three Types of Galaxies

The Three Types of Galaxies


Elliptical galaxies are collections of stars that remain pretty close together because of the gravitational attraction between them. There is not a certain known rotation axis, so the stars in the galaxy show a wide range of orbital paths. The motions of stars are not entirely random; there is a degree of organization in the direction of these motions, and this determines the overall shape of the galaxy. Elliptical galaxies have a plain appearance, and some elliptical galaxies are nearly circular in shape, and some elliptical galaxies are extremely stretched out or flattened. The ones that are spherical are classed as E0 galaxies, and those that are flattest are E7, the types in between have the numbers E1 to E6. Elliptical galaxies show a larger range in brightness, some can be up to 10 times brighter than the brightest spiral galaxies, and the dullest ellipticals can be 1000 times less luminous than the dullest spiral. An elliptical galaxy is giv...