Why is it possible to see a cirular rainbow when you are in an airplane,yet it is impossible from the ground?

Question

Why is it possible to see a cirular rainbow when you are in an airplane,yet it is impossible from the ground?

Answer 1

The horizon gets in the way on the ground.

Its that simple.

Answer 2

When your on the ground you don't have rain drops falling beneath you. A rainbow happens when sunlight reflects off of rain drops. On the ground they're only above you.

Answer 3

As the light from the sun enters the raindrop and is refracted and reflected off the back of the raindrop into your eye. Different wavelengths of light refract at different angles. For example, blue light is reflected back at a sharper angle (40 degrees) than red light (42 degrees).

A rainbow is created by millions of raindrops, each at a different angle and each reflecting a different color into the eye of the beholder. On the ground the each raindrop only pass the visible angle range once, 40 to 42 degree. However when you're on an airplane it can reflect twice at 40 to 42 degrees and -40 to - 42 degree which creates a whole circle.