There are millions to billions of stars per galaxy, which rotate around a common center. Galaxies are made up of whatever gas and matter that its gravity has accumulated from outerspace. All these elements in a galaxy are held together by gravity . Galaxies are randomly clustered throughout space. There is an infinite number of galaxies in our universe.
Galaxies come in many different shapes and sizes.
The range of different sizes that galaxies are, is amazing. We live in the Milky Way galaxy, which is a very large, spiral galaxy. Birth Galaxies, like stars, are born from gigantic cosmic clouds . Scientists and Astronomers believe that galaxies start out with small pieces, such as gas clouds and star clusters, that slowly merge together. Galaxies are most likely born from cosmic clouds that are made of Hydrogen and Helium , the reproductive ingredients for stars.