The Milky Way is a huge group of many billions of stars called a galaxy. There are more than a billion other galaxies just like the Milky Way in the universe.
The Sun, Moon, Earth, and all the planets form only a small part of our Milky Way. The rest is made up of clouds of dust and gas, and over 200,000,000 stars. Some of these stars are large and some very small.
To get an idea of just how vast the Milky Way is, think in terms of how fast Light travels. For light to travel from the sun to the earth, it takes 8 minutes. But for light to travel from one end of the Milky Way to the other, it takes 100,000 years.
The Milky Way is shaped like a pancake, with stars fanning out from the center in a spiral shape.