Meteor Shower? © Niki & Jessica Mariskanish
Stars are balls of burning gases. The outer gases are so hot that they boil. The center of the star has extreme pressure and heat that are high enough to cause fusion.
Fusion produces energy. The energy we see is light. Which is why, to us, the stars shine.
The hottest stars are the youngest and shine with a blue-white light. Older, cooler stars shine with a red light. Other stars shine yellow or orange because they're in the middle of their lives. Besides age, a star's color depends on how big it is, how hot it is, and how much energy it produces.
We shot the picture of stars on the left over a period of two hours. You can see they have different colors.