Galaxy cluster

Okay, so imagine you have a bunch of stars, planets, and space gas all hanging out together in a big group. That's kind of like what a galaxy is. Now, imagine that there are LOTS of galaxies all hanging out together in an even bigger group. That's called a galaxy cluster!

Sometimes, the galaxy cluster is so big that it's hard to see all the individual galaxies that make it up. It's kind of like trying to see all the ants in an ant hill.

Galaxy clusters are really fascinating because they're some of the biggest structures in the entire universe! They're made up of so many different things, like stars, planets, gas, and even dark matter. Scientists study galaxy clusters to try and figure out how they formed and how they affect the universe around them.

So, basically, a galaxy cluster is a really big group of galaxies hanging out together in the universe. Cool, right?