The color of a star depends on its mass. Galaxies form stars with a range of
masses, so we find stars with a range of colors inside galaxies.
Massive stars are hot and bright bluish-white in color. Smaller stars are cooler and
have dimmer, yellow to red colors. Galaxies with blue stars are easy for us to see,
because the blue stars are so bright.
Small Magellanic Cloud
Large Magellanic Cloud
Andromeda Galaxy
NASA / Amazing Space Student Background Reading: About Galaxies
Massive blue stars use up their fuel fast, so their lives are short. Yellow and red
stars use their fuel more slowly. They have much longer lives than blue stars.