The Hubble telescope captured galaxies in the eastern direction of the universe. Images came back proving that galaxies are made up of different colors. What would explain the reason for the make of colors in galaxies?

1 Answer
Nov 5, 2017

In essence it is related to the average age of the stars.

Explanation:

Galaxies early on in their lives are actively forming hot, new stars and appear more bluish. Older galaxies are forming fewer new stars and their constituent stars are older on average so appear more reddish.

There are complicating factors ... intervening dust and gas to name but two, but this is it in a nutshell.