What are galaxies?

A galaxy is a large group of stars, gas, dust, and dark matter held together by gravity.

There are three main types of galaxies: spiral, elliptical, and irregular.

Examples of spiral galaxies include the Milky Way, Andromeda, Triangulum, and Whirlpool.

Elliptical galaxies have an elliptical shape and appear smooth and featureless. Examples of elliptical galaxies include M87 and M49.

Irregular galaxies do not have a distinct shape and are usually smaller than spirals and ellipticals. Examples of irregular galaxies include the Large Magellanic Cloud and the Small Magellanic Cloud.

Galaxies can also be classified by the amount of star formation they contain. Active galaxies are galaxies that contain lots of star formation and are usually spiral galaxies. Quiescent galaxies are galaxies with little to no star formation and usually have an elliptical shape.

Galaxies can also be classified according to their distance from us. Nearby galaxies are those within a few million light years, while distant galaxies are those that are billions of light years away.

Thank you for reading. Create summary videos with Kimavi.