twinkle twinkle little star

Twinkle, twinkle, little star,
How I wonder what you are!
Up above the world so high,
Like a diamond in the sky.

I was out walking last night and noticed a twinkling star.​

courtesy of mocomi.com

The same turbulence also causes stars to appear to change colors rapidly. Refraction is the shift of light when it passes through a medium leading to bending. Reflection is the bouncing back of light when it strikes a medium, such as Sun to Moon to Earth.