What is a cloud with a rainbow in it. It was seen in the sky about a weekago.?

Answer 1

A rainbow is caused by sunlight being refracted and reflected by raindrops not water droplets. The sun has to be lower than 42° for a rainbow to be seen.

There are many other optical phenomena that can produce colours in the clouds or sky. Haloes are caused by refraction of sunlight through ice crystals. The commonest is the 22° halo which forms a ring round the sun or the moon. Parhelia or sundogs are bright spots of colour that occur on the 22° halo either side of the sun.

Irisation (or iridescence) is a form of the corona that is caused by diffraction of sunlight by water droplets in the cloud. Irisation can appear as bands of colour, particularly pink and green, through cloud near the sun.

Answer 2

Rainbows are caused when humidity (water droplets in the air) refract (bend) sunlight and break white light into the various colors of the spectrum.

It happens the same way as a normal rainbow, it's just that in this case the light is being refracted by the moisture in the cloud, instead of by free-floating humidity in the air. Hope that makes sense.

If you want to read deeper meaning into it, when you see one of these it is your lucky day and you should go buy a box of cracker jacks immediately because you will get that one special prize that's your freakin' favorite, you know, the one with the little plastic monkey and the rubber band.