Why earth is called blue planet As soon as white light strikes the earth’s surface, it is absorbed by the earth’s water reservoirs, which absorbs all other wavelengths of light except blue, with only blue light being reflected back to space from the earth.

The planet earth surface is covered by almost 70% of water and the rest 30 per cent constitute solid surfaces like continents, islands, mountains.

Hence when we see the earth from space it looks like a blue planet because the visible light radiation coming from the son contains VIBGYOR means violet, indigo, blue, green, orange and red, they together form white light.

But when white light falls on the earth surface its water reservoir absorbs the other wavelengths of light except blue and only blue light reflected back to space, that’s why we see the earth as the blue planet.