eli5: If blue portion of the white light spectrum is absorbed (scattered) in the atmosphere due to Reileigh scattering, does it mean that what we perceive as, say, purple colour would look different without the atmosphere ? (because more of the blue spectrum would be shining on the object)

Question

eli5: If blue portion of the white light spectrum is absorbed (scattered) in the atmosphere due to Reileigh scattering, does it mean that what we perceive as, say, purple colour would look different without the atmosphere ? (because more of the blue spectrum would be shining on the object)

In: Physics

Answer 1

Scattering and absorption are different processes. We do not see light that is absorbed, but we do see light that is scattered. In the case of blue light from the sky, it reaches the ground (since we see it) and illuminates objects. It’s more diffuse lighting than the remaining spectrum from the sun, which might affect how objects look, but it’s not at all absent.

The other factor to consider is that we don’t perceive absolute color, but within some range we adjust to the ambient color. The sun actually does emit less violet and red light than green/yellow, but if we boosted those frequencies in the ambient lighting, we would perceive an object’s colors as more or less the same. This effect is called chromatic adaptation.