Why does the sky turn red at sunset?

The sky turns red at sunset because the sunlight has to travel through more air. When the sun is high up, the blue light goes straight to us. But when it’s low on the horizon, like during a sunset, the light has to go through a lot of air. The blue light gets scattered away, and the red and orange light stays. That's why we see red skies at sunset.

Take the quiz →

Examples

Imagine looking through a thick curtain, only the brightest colors come through.
When you pour water from one glass to another, the first color that shows is usually the most intense one.
If your friend wears a blue shirt in bright sunlight and moves into shade, their shirt appears darker and less vibrant.

Ask a question

Discussion

Recent activity

Categories: Physics · sunset· light scattering· atmosphere· optics· sunlight