When sunlight and raindrops combine to make a rainbow, they make a whole circle of light in the sky. However, it is quite rare to spot: sky conditions have to be just right for it, and the bottom part of a full-circle rainbow is usually blocked by the horizon. That’s why rainbows are commonly seen as arcs across the sky, not as circles.
Viewers on the ground can only see the light reflected by raindrops above the horizon. To see a full circle one has to get up very high. Even a high mountain won’t be enough.
The arc’s size also depends on the position of the Sun: the lower the sun is, the higher is the top of the rainbow.
So who are the lucky witnesses of a full-circle rainbow? Pilots!
Image Credit: Full circle rainbow was captured over Cottesloe Beach near Perth, Australia in 2013 by Colin Leonhardt of Birdseye View Photography.
#AsgardiaSpaceNation
