What
is a rainbow?
A rainbow appears when sunlight and water meet. They
are caused by the refraction and dispersion of the suns light by rain or
other water droplets in the atmosphere. Rainbows can be seen not just when
its raining but also on misty or foggy days, in the spray of a waterfall,
and even in dew, basically they can appear whenever there are water droplets in
the air and there is sunlight shining from behind at the right angle. Its
called light refraction, and on a sunny day, with a hosepipe, you can even
create your own rainbow in the garden.
A full rainbow is actually a complete
circle, but from the ground we see only part of it, which is why its an arc.
In fact, given the right conditions, you could see an entire
circular rainbow, but you did need to be very high up in the air.
The colours of the rainbow are
generally said to be red, orange, yellow, green, blue, indigo, and violet the
spectrum. We often say, all the colours of the rainbow. These colours
are created by 2 things
Sunlight is made up of the whole range of colours
wavelengths that the eye can detect. When combined, the range of
colours look white to the naked eye, what we call sunlight.
This property of sunlight was first demonstrated by Sir Isaac Newton
in 1666.
When the light of all these different colours is
refracted in different ways, as it passes from one medium air, for
example into another water or glass, for example the colours separate,
ranging from violet on the bottom to red on the top.
If you are very lucky, you might see a
double rainbow. In certain conditions you can see another, fainter
secondary rainbow above the primary rainbow. The primary rainbow is caused from
one reflection inside the water droplet. The secondary rainbow is caused by a
second reflection inside the droplet, and this re-reflected light exits the
drop at a different angle. This is why the secondary rainbow appears above the
primary rainbow. The secondary rainbow will have the order of the colours
reversed, too, with red on the bottom and violet on the top.
There are many
legends from different ancient cultures, all created to explain them,
because let us face it, rainbows are among the most beautiful of natures
displays.
One of the earliest literary mentions of
a rainbow is in the bible Genesis 9, as part of the flood story of Noah where
it was a sign of Gods covenant to never destroy all life on earth with a global
flood again.
In the UK they tend to be associated
with good fortune, but its unlucky to look at a rainbow through glass.
In Ireland leprechauns hide their pots
of gold at the end of the rainbow.
There was a belief among ancient
Polynesians that a rainbow was a ladder that their heroes climbed to reach
heaven.
One old wives tale says that a house
that is over arched by a rainbow will soon experience a disaster, or if you
walk through the end of a rainbow, your family will experience a disaster
within a year.
In ancient Greece people thought
that Iris, wife of the god Zephyrus, caused rainbows. Iris was a messenger
between mortals and the gods. She ran back and forth, dressed in shimmering
multicolored robes. The word iridescence comes from Iriss robes.
The Karens, a group of people in Burma,
once considered rainbows to be dangerous demonic spirits that devoured the
souls of humans and caused sudden or violent deaths. They thought that such
activity made the rainbow thirsty enough to appear in the sky and dip down to
Earth to drink water.
Rainbows have been used as a symbol of
hope or social change for centuries The rainbow featured as a symbol of the
Cooperative movement in the German Peasants War in the 16th century, and even
in these modern times the rainbow still has the power to move us Rainbow flags
are used as a symbol of peace in Italy, and they have been used as a symbol of
gay pride and LGBT social movements since the 1970s. In 1994, Archbishop
Desmond Tutu and President Nelson Mandela described the newly democratic
post-apartheid South Africa as the rainbow nation.
The fact is a rainbow is not
really a thing and it does not exist in a particular place, I am sorry to tell
you, you will never reach that pot of gold, as you walk towards the end of
a rainbow, it will appear to move farther away, because a rainbow is simply an
optical phenomenon that appears when sunlight and atmospheric conditions are
just right, and the viewers position is just right to see it, but no one ever
sees the same rainbow, which is a kind of magic all its own.