What causes a rainbow?  Rainbow. Photo copyrighted.  The
technical details of rainbow formation were first analyzed by
Isaac Newton in 1665. His brilliant optics work concerning
reflection and refraction certainly does not detract from the
beauty and promise of the rainbow. On the contrary, Newton's
scientific insights show the marvelous complexity of creation.
The rainbow is a gracious pledge that God will not destroy the
earth a second time with a worldwide flood (Genesis 9:11-17):
“I have set my rainbow in the clouds, and it will be the sign of
a covenant between me and the earth… Never again will the waters
become a flood to destroy all life.” (Genesis 9:13,15).  A
rainbow occurs when raindrops and sunshine cross paths. Sunlight
consists of all the colors of light, which add together to make
white illumination. When sunlight enters water drops, it
reflects off their inside surfaces. While passing through the
droplets, the light also separates into its component colors,
which is similar to the effect of a