What Causes Double Rainbows?
What Causes Double Rainbows?
How These
Colourful Meteorological Phenomenons Are Caused?
Regular rainbows occur when moisture
in the air refracts sunlight in such a way that it is broken up into its
constituent colours. The phenomenon occurs when the sun is positioned behind
you and sunlight passes through the airborne water. The light refracts (bends)
inside the droplets and the white light is broken up. Each colour has a
different wavelength so, depending on the angle of refraction, a different
colour of light will be reflected outwards; the result of this process is what
we observe when we see a rainbow.
Every rainbow is accompanied by
another, secondary rainbow, but it's usually too dim to see. This double
rainbow effect is due to the continued reflection of light inside each water
drop. Sunlight is actually reflected twice inside a drop: Once to produce the
primary rainbow and a second time at the back of the drop. This second
reflection inverts the light but undergoes the same refraction, so exits in the
same way as before-though upside dpown. This second reflection reduces the
intensity of the sunlight, but it also produces a second inverted rainbow,
creating a double arc of multicoloured light.
