Galaxy color–magnitude diagram

Do you know what a galaxy is? It's like a big group of stars, dust, and gas that is held together by gravity. Imagine a bunch of stickers stuck on your hand, they all stick together because of the glue on the back.

Now, imagine we take a picture of a bunch of galaxies in space. We can see how bright they are and what color they are. Just like how stickers can be different colors and sizes.

A galaxy color-magnitude diagram is a way to show us how bright and colorful galaxies are. It's like coloring with different crayons on a piece of paper.

The brightness of the galaxy is called magnitude. Magnitude is like how bright a light bulb is, but we measure it differently for stars and galaxies.

So, on a color-magnitude diagram, we put brightness (magnitude) on one axis and color on the other axis. We use different colors to represent slightly different parts of the galaxy's light. Kind of like how we use red, blue, and green to make different colors on a screen.

Using this diagram, we can see different patterns in the colors and brightness of galaxies. It can help us learn about how galaxies form and evolve. Kind of like how we can learn from the pictures we draw using different crayons.