The Milky Way galaxy is about 100,000 light-years across.

Our galaxy, the Milky Way, is enormous compared to Earth. It stretches about 100,000 light-years, meaning light takes 100,000 years to travel from one side to the other. Since light travels about 300,000 kilometers every second, this distance is almost impossible to picture. The galaxy contains billions of stars, planets, and other objects, making it one huge cosmic city.