Altitude, landscape, and climate change dramatically as you move around the world, but one factor is present almost everywhere. All the diversity of the world is covered by the blue sky. So why is the sky blue? This is not a reflection of Earth’s oceans. The real explanation requires some particle physics.

We see blue above us due to the interaction of light from the Sun with the Earth’s atmosphere. The spectrum of visible light includes a variety of colors ranging from red light to violet. When all the colors are mixed, the light appears white, Mark Chenard, a meteorologist with the National Weather Service, told LiveScience. But when white light from the sun reaches Earth, some colors begin to interact with molecules and small particles in the atmosphere, he said.

Each color in the visible light spectrum has a different wavelength. For example, red and orange light waves have longer wavelengths, while blue and violet light have much shorter wavelengths. These are shorter wavelengths of light that are more likely to be scattered or absorbed by air and gas molecules in Earth’s atmosphere and re-emitted in a different direction, Chenard said. Molecules in the atmosphere (mostly nitrogen and oxygen) scatter blue and violet light in all directions through a phenomenon called Rayleigh scattering. This is what makes the sky blue.

According to astronomer Ed Bloomer of the Royal Greenwich Observatory in the United Kingdom, there are several reasons why we see the sky as blue rather than purple, although violet light is also scattered. First, the sun does not provide proper illumination. in all colors; Since it contains more blue light than violet, more blue light is scattered. Bloomer also told Live Science that our eyes don’t respond equally to all colors; They are less sensitive to violet light, which means we are more likely to see shades of blue rather than purple.

This preferential scattering of blue light also affects the colors of sunrise and sunset. As a particular point moves further away from the sun at sunset, sunlight must travel further through the atmosphere to reach your eyes. When sunlight reaches you, all the blue light has dispersed. As a result, only orange, red and yellow wavelengths are left to color the sunset.

Bloomer said the vast blue sky is created by a number of factors. If you were on another planet, you might be looking at a completely different color depending on the molecules in the other world’s atmosphere, dust particles swirling around, or the spectrum of light from a nearby star. Source