Where is My Pot of Gold?
By Ken Kostura
Forecaster
One
of the most spectacular atmospheric phenomena is the rainbow. From the Biblical
story of Noah in Genesis 9:13,15 to the song Somewhere over the Rainbow
immortalized by Judy Garland in the Wizard of OZ, the rainbow has been a popular
subject for singers, poets, lovers and painters. An observer on the ground
views a rainbow as a colorful arch shape covering a large segment of the sky.
With varying degrees of clarity, six distinct bands of color can be seen from
the out most band of red gradually blending to orange, yellow, green, blue and
ending with an innermost band of violet. The two basic ingredients for
creating a rainbow are sun and rain. Typically, rainbow can be viewed
when the observer is situated with the sun on one side and a rain shower
occurring in the opposite part of the sky. Like in real estate, location is
critical. The sun must be at a low in the sky so that the rays of light pass
through the raindrops at the correct angle. The sun must be facing the rain,
so when one observes a rainbow, the sun will always be at your back.
When
sunlight strikes a raindrop the white light of the sun is refracted, it
separates into the colors of the visible spectrum of light. Light which appears
to be white is really composed of a mixture of red, orange, yellow, green, blue
and violet light. After sunlight hits a round raindrop, the light is separated
into the colors and each color of the light travels to the back of the drop
where the colors bounces off at an angle. The rainbow light is reflected
to the eye at an angle of 42 degrees to the original ray of sunlight. The
separate colors pass through the front face of the raindrop, below the point
where the sunlight first entered. This process occurs through millions of
raindrops at the same time resulting in a rainbow.
Many
cultures see the rainbow as a bridge between heaven and earth. The rainbow has
become a sign of renewed hope and something lucky to look upon. An old European
Legend is that there is a pot of gold at the end of a rainbow. Let's
examine this in more detail. The bow shape is actually part of a cone of
light that is cut off by the horizon. If you are traveling toward the end of a
rainbow, it will move ahead of you, maintaining its shape. Thus, there is no real
end to a rainbow, and no pot of gold waiting there.
There
are times when nature allows you to double your viewing pleasure with
spectacular double rainbow. The secondary rainbow lines up parallel to the
primary rainbow with colors usually appearing dimmer than the primary bow. The
secondary bow is always visible above the primary bow and it suspends a larger
arc across the sky. In contrast to the primary rainbow, the secondary
rainbows colors appear in a reverse order with the violet being the out most
part of the arc and the red on the inner of the arc. The secondary rainbow
develops when some of the light fails to escape the raindrop and bounces off
the inside of the drop a second time, then exits just below the location of the
light creating the first rainbow. This produces a dimmer, mirror image of
the primary rainbow called the secondary rainbow.
Keep
searching the sky for those treasures in the nature.
Rainbow Colors
Jamaican Rainbow 12-2004