Okay kiddo, so first let me explain that the Milky Way is our home galaxy. It's like our big family, with stars, planets, and other stuff. And like any big family, sometimes there are smaller groups within it - those are the satellite galaxies!
Think of it like this: imagine you have a really big bedroom with lots of toys and things to explore. But then your friend comes over and she brings her own toys too. Her toys are like the satellite galaxies that come and hang out with the Milky Way.
These satellite galaxies are smaller than the Milky Way, but they are still really cool! They have their own stars and planets, just like we do in the Milky Way. Some of these satellite galaxies are close enough to us that we can see them in the sky with our own eyes!
But even though they are smaller, they still play an important role in the family of the Milky Way. Scientists study these satellite galaxies to learn more about the bigger family and how all the different parts fit together.
So, that's the long and short of it - satellite galaxies are smaller groups of stars and planets that hang out near the bigger Milky Way family. They're cool and important, just like you and your friends!