so visible photons to our eyes have wavelengths around 400-750 nm, but my simple question is, how does this wavelength orientate itself? when i think of a wave, i think of a vertical movement up and down, but vertical is relation to the way i view up and down which is in relation to gravity on this planet
so how does wavelength orientate? if it's an up and down movement, then what dictates up and down, i suppose i'm asking- what is wavelength?