Question: How do stars have different colours?

Nick Wright answered on 11 Mar 2014:

Stars are different colours depending on what temperature they are on their surface, kind of like how different flames can be different colours depending on what temperature they are. The hottest stars (and flames) are bluer than the cooler stars (and flames) because blue light has more energy in it than red light. This may seem odd to us because we are used to thinking of blue being cold and red being hot, but actually blue light is more energetic (and hotter) than red light!