How Do Astronomers Classify Galaxies?

by Celestia McPark, age 7

Galaxies have more designs than you think. There are three types of designs: spiral, elliptical, and irregular. Despite their different shapes, they are all made up of gas, stars, and particles.

Spiral galaxies are said to look like pinwheels made up of stars, gas, and dust. They are also the most common shape, as they make up 60% of the unknown galaxies.

Elliptical galaxies have old stars and dust with a surrounding flat disk of gas. They are shaped like stretched-out circles. Some elliptical galaxies are more stretched out and are smaller than others. Unlike spiral galaxies, only about 15% of galaxies have this shape.

Irregular galaxies do not have normal shapes and can vary in size, which can affect the clarity of their nucleus. Irregular galaxies may make up about a quarter of all known galaxies.

Galaxies vary in size; some are small and some are big, but they all have one thing in common: they have a black hole in their center. The universe has billions of star systems called galaxies, so there is still a lot more for us to discover!

[Sources: NASA; Britannica Kids]