Co-Authored By:
In theory, all rainbows are doublerainbows, but since the secondary bow is always fainter thanthe primary, it may be too weak to spot in practice. Secondaryrainbows are caused by a double reflection ofsunlight inside the water droplets.
Moreover, are there always double rainbows?
A double rainbow occurs when sunlight hits a partof the raindrop at a different angle of incidence, at which thelight-path is refracted>reflected>reflected>refracted.Also, because there is another internal reflection thecolours are inverted. So every rainbow has a primary andseconday arc.
Furthermore, what causes double rainbows?
As the light reflects back out of the raindrop, it bendsagain. That internal reflection produces the arc of sunlight spreadout across its spectrum of colors -- a rainbow. Pigott saida double rainbow is formed when there are two reflectionsinside a raindrop.
Few people have ever claimed to see even threerainbows in the sky at once. Scientific reports ofthese phenomena, called tertiary rainbows, were so rare— only five were reported in 250 years — that until nowmany scientists believed they were as real as a pot of goldat the end of a rainbow.