“My heart leaps up when I behold
A rainbow in the sky.”
(This is from a poem by William Wordsworth, linked here.)
A rainbow is a beautiful natural phenomenon created by the angle of light from the sun to the viewer’s eye. At this particular angle, the white light is broken into a spectrum of colors: red, orange, yellow, green, blue, violet. Red is always at the top. Purple is always at the bottom. To understand more about how this happens, go here.