Why can't the human eye see all the colors in a rainbow?

Question

I read there are actually more colors than what we see.

Answer 1

The words "color" and "light" are defined in terms of what we can see. So by definition, we can see all the colors there are in a rainbow.

The only way you can say there are "colors" that we can't see, is if you can compare it to some other visual system that *can* see those colors. For example, if you are color blind, you could talk to another person and they could say they distinguish more colors than you can. (E.g. they can distinguish between reds and greens, while to you, reds and greens just look like different shades of the same color.)

Animals can also distinguish colors that we cannot distinguish. For example, birds have 4- and in some cases (like pigeons) 5-color vision, while we have only 3-color vision. I.e. we have only 3 types of color receptors in our eyes that respond to different ranges of light, while pigeons have 5. Thus a pigeon can recognize differences in two colors coming from a rainbow that look identical to us. So compared to a pigeon ... all humans are partially "colorblind."

Insect eyes can also respond to light in the ultraviolet range of the spectrum. So the rainbow will look quite different to them.

However, we have the brain that allows us to think "wow, that rainbow is beautiful", while insects have a brain that has thoughts more like " . . . . . . "

Answer 2

Visible light is one type of Electromagnetic Radiation. Electromagnetic radiation is energy that travels in waves, one of the properties of these waves is the wavelength. Visible light is Electromagnetic Radiation that has wavelengths between 400 and 700 nanometers. However, there are many other types of electromagnetic radiation that have wavelenghts greater or smaller than this. Some of them include, X-rays, Ultraviolet Light, Infrared, Microwaves, and Radio Waves. Visible light is only different from these other forms of waves because of the wavelength, otherwise they are identical in nature.

Answer 3

because the "prism" in our eyes is not properly curved,
if you look through a prism than you can see them better.