Rainbows
A rainbow is one of our atmosphere’s most exquisite and marvelous creations;
"one of the most spectacular light shows observed on earth" (Ahrens,

1998). When a person views a rainbow, they are getting a personal light show
that no other person can see as they do. Humphreys points out that: "Since
the rainbow is a special distribution of colors (produced in a particular way)
with reference to a definite point - the eye of the observer - and as no single
distribution can be the same for two separate points, it follows that two
observers do not, and cannot, see the same rainbow." (Humphreys, 1929). Of
course, a camera lens will record an image of a rainbow which can then be seen
my many people (Lynds, 1995). A rainbow is essentially made up of seven
brilliant colors: red, orange, yellow, green, blue, indigo, and violet;
moreover, it is comprised of many coloration that the eyes cannot see. No
painter can manufacture the colors of the rainbow, for they create color by
mixing, but no mixing will give red, green, or purple. These are the colors of
the rainbow, though between the red and the green an orange color is often seen
(Aristotle, 350 BC). To understand how the awesome production of a rainbow
occurs is a feat of physics and mathematics. The two most important ingredients
are light and drops of water. The manner and position in which the light and
water droplets transverse, and the reactions between the two, are complex
formulas of nature. Additionally, certain circumstances make it possible for a
rainbow to occur. You cannot have a rainbow without some source of light. It is
possible to create an artificial rainbow utilizing artificial light, but for
this paper, I will only use instances and circumstances of naturally occurring
light which produce naturally occurring rainbows. The sun is nature’s primary
source of rainbow creating light; however, occasionally, the light of the moon
can produce a rainbow. For a lunar rainbow to occur the conditions have to be
just right. The moon has to be a full moon, which only happens once a month. The
light of a full moon is a faint light, so the lunar rainbow will never be as
prominent as the solar rainbow. Additionally, the full moon has to be either
rising or setting. A naval officer, V. E. Mikkelson, described his reaction when
he learned that the spotlight he saw was actually a lunar rainbow: The strange
phenomenon I was viewing was a rainbow generated by moonlight! It was being
formed by moonlight passing through rain trailing from one of the fluffy cumulus
clouds. The rainbow was composed of the standard colors, but they were softer
and paler than those generated by direct sunlight. They were what I can only
describe as pastel. I was truly entranced. I have seen many of nature\'s
beauties, but none have ever impressed me so powerfully (Mikkelson, 1994) This
is a rare phenomenon. Captain Mikkelson has been a seaman for over twenty years
and has only viewed this one lunar rainbow; moreover, he has spoken to numerous
career seamen and none reported ever seeing such a magnificent sight. Another
essential component of the rainbow is drops of water. Again, water drops from
sprinklers or the sprays emitted from waterfalls can produce a rainbow, but I
will focus on water drops that fall from the sky. A raindrop is nature’s
reflective mirror in the sky. The smooth, yet internally curved, surface of a
raindrop can refract and reflect light. A typical raindrop is spherical in
dimension and thus has a symmetrical effect on light. Lynds (1995) points out
that the "purity" of the colors of the rainbow depends on the size of
the raindrops. Large drops (diameters of a few millimeters) give bright rainbows
with well defined colors; small droplets (diameters of about 0.01 mm) produce
rainbows of overlapping colors that appear nearly white. When it rains, the
droplets are never the same exact size and shape; thus, a rainbow occurs in a
range of colors. Sunlight slows and bends when it enters a raindrop. Some of the
light strikes the back of the drop at such an angle that it is reflected within
the drop, this is the critical angle of 48º. Any angle greater than this and
the light bounces off the back of the raindrop and is internally reflected
towards our eyes. Each light ray bends differently from the others, so each
angle is slightly different; therefore, the light is dispersed into a spectrum
of colors from red, angle of