It’s not uncommon to see a rainbow behind or ahead of a rain storm, but have you ever seen a double rainbow?
A ray of sunlight passes through a raindrop, reflecting off the back of the drop at varying angles. Along with this reflection is refraction of light that causes of a spectrum of colors: red, orange, yellow, green, blue, indigo and violet. Certain angles and “bending” reflect light better for refraction to occur, and the amount of light refraction corresponds to wavelength and color. For example, blue light is always refracted at a deeper angle than red light. This is the reason blue is found at the inside of the bow and red on the very outside.
Nature’s natural color spectrum always elicits the same pattern (red, orange, yellow, green, blue, indigo, violet) when light is refracted, commonly known from the Roy G. Biv mnemonic. While a primary rainbow is visible when light is reflected once off the back of a raindrop, a secondary and usually dimmer rainbow is spotted when light is reflected twice in a more complicated pattern. The colors of the second rainbow are inverted, with blue on the outside and red moved to the inside. The second bow appears dimmer or cloudier because much more light is released from two reflections, and both bows cover a larger portion of the sky.
