Billions of galaxies exist across the universe. Our home, Planet Earth, is located in a galaxy called the Milky Way.
Many of the stars in the Milky Way galaxy are packed in its nucleus, or central region. Flat, slim circles that contain many stars envelop the nucleus. Made up of dust and gas clouds, these stars are organized in a spiral pattern that measures 100,000 light years across.
There are three main galaxy types: spiral, elliptical, and irregular. Spiral galaxies are made of gases, which form new stars. In contrast, elliptical galaxies do not have as much gas. Elliptical galaxies also come in different shapes and sizes, whereas irregular galaxies—as their name suggests—do not really have a shape. Each type of galaxy is made up of a lot of dust and young stars, which are also called baby stars.
On a clear, dark night, step outside! You’ll probably be able to see the light from many of the stars and planets that form the Milky Way galaxy.
[source: Explore the World of Space and the Universe]