What are the different types of galaxies in the universe?

Galaxies are massive systems of stars, gas, and dark matter that are held together by gravity. They come in various shapes and sizes, and are classified into three main types: elliptical, spiral, and irregular galaxies.

• Elliptical galaxies are shaped like a stretched-out sphere or football. They are the most common type of galaxy in the universe, and are usually composed of older stars.
• Spiral galaxies have a disk-like shape with arms that spiral out from the center. They are typically younger and contain more dust and gas, which make them more active in terms of star formation.
• Irregular galaxies do not have a regular shape or structure, and are typically smaller than other types of galaxies. They can be further subdivided into two categories: those with a lot of star formation activity, and those without.

It's important to note that these classifications are not mutually exclusive, and many galaxies have characteristics of more than one type.