rainbows are circles

spring rains are a good time to keep an eye out for rainbows.  look for rainbows whenever the the sun is behind you, and the rain is in front of you. did you know that all rainbows are circular? it’s just that the horizon interrupts the full circle so we only see part of an arc. i just learned that! people in airplanes can occasionally see full circle rainbows. i went down the rabbit hole of rainbow optics today. i’ve included the quote below which best tries to explain the phenomenon simply.  anyway, this circle of winter weeds stems reminds me of both rainbows and rabbit holes. two of my favorite spring things.

winter weeds

p.s. “Rainbows don’t exist! They are nowhere in space. You cannot touch them or drive around them. They are a collection of rays from glinting raindrops that happen to reach our eyes. Raindrops glint rainbow rays at an angle of 42 degrees from the point directly opposite the sun. All the drops glinting the rainbow are on the surface of a cone with its point at your eye. They can be near and far. Other drops not on the cone also glint sunlight into rainbow colors but their rays do not reach our eyes. We only see those on the cone. When you look down the cone you see a circle. So rainbows are circles!”