Ultimately, the question “Why is the sky blue?” is not just about physics—it is about the spirit of inquiry. It shows how even the simplest observation can lead to profound truths. The sky appears red because small particles of dust, pollution, or other aerosols also scatter blue light, leaving more purely red and yellow light to go through the atmosphere. The short answer is that sunlight gets scattered when it hits our atmosphere. Blue light has the shortest wavelength, so it bounces around the atmosphere. If you’ve ever sprawled on the ground and stared up on a bright afternoon, you’ve probably wondered why the sky chooses blue and not green or pink. The truth is, the colour above us is a kind of optical trick, performed by sunlight and air working together.
