Short · Light and color
Why is the sky blue but sunsets red?
Air scatters blue light nearly six times more than red. Drag the sun to the horizon and its light crosses nearly forty times more air, so the blue is scattered out before it reaches you.
Play with this now
Opens Sunset Lab. Change the same thing yourself.
Transcript
Why is the sky blue, but sunsets red? Sunlight is every color mixed together. Air molecules scatter blue light nearly six times more than red, so at noon, blue reaches you from every direction. Now drag the sun to the horizon. Its light crosses nearly forty times more air. Along the way, the blue gets scattered out. What's left is orange and red. Play with this now at Explainer Tools dot com.