Why do sunrises also look red?

In one line

The rule

Light with shorter wavelengths (like blue) is scattered more by the atmosphere than light with longer wavelengths (like red).

This is called Rayleigh scattering.

Let's understand it simply

Imagine you are watching a cricket match in the evening. The sun is low, and the sky looks orange or red. This happens because sunlight has to travel through a lot more air when the sun is near the horizon (at sunrise or sunset) than when it is overhead. The air acts like a filter. It scatters (spreads out) the blue and green parts of sunlight in all directions. Only the red and orange parts are left to reach your eyes, making the sun and sky look reddish.

How it works

1. Sunlight is made of many colours (like a rainbow).
2. When the sun is low (at sunrise), its light travels a longer path through the air.
3. The air has tiny particles and gases that scatter blue light more than red.
4. Most of the blue and green light gets scattered away from your line of sight.
5. The red and orange light, which scatters less, passes through and reaches your eyes.

The story behind it

This effect was explained by Lord Rayleigh, a British scientist, in the 19th century. He was studying why the sky is blue and discovered that the way light scatters in the air depends on its colour (wavelength). His work helped us understand many things about light and the atmosphere.

Where you see it in real life

• Watching the sunrise from a train window → The sun looks red because of the long path through the air.
• Sunset at the beach → The same effect makes the sun look orange-red as it sets.
• Diwali rockets at night → The smoke can make streetlights look reddish through the haze.
• Dust storms in Rajasthan → The air is full of dust, making the sun appear even redder at sunrise or sunset.
• During monsoon, after rain → Sometimes the sky looks more colourful because of extra water droplets scattering light.

Why it matters

• Helps us understand weather and pollution (more dust means redder sunrises).
• Used in photography and art to create beautiful scenes.
• Important for pilots and sailors to judge weather conditions.
• Shows how light behaves, which is useful in science and technology.

Common mistakes

• Thinking the sun itself changes colour (it doesn't; only the light reaching us changes).
• Believing only sunsets are red, not sunrises (both are red for the same reason).
• Forgetting that clouds, dust, and pollution can make the effect stronger.

Remember it

Red sunrises happen because the blue light gets scattered away, leaving the red light for us to see.