As I walked out of Safeway last week on a rainy morning that was just clearing, I noticed a beautiful phenomenon looking west toward the Selkirk Mountain, a rainbow. Who doesn’t like rainbows? Watch what happens when a rainbow suddenly, almost magically, appears on the horizon, a delicate burst of color gently washed across the sky. People stop what they’re doing. Stare. Snap photos with their iPhones. And smile!
A rainbow’s ability to bring joy to just about anyone is probably why they’re painted on kids’ cheeks at fairs. Why they’re used to decorate birthday cakes, garden flags and bedding. Why they’re mentioned in lyrics, poems and other writings. Why they’re the stuff of folklore across many countries and peoples, often signifying a link to the heavens.
So what, exactly, is a rainbow? Strangely, it’s just an optical illusion. We see rainbows when light strikes drops of water. The light is refracted, or changes directions, then is reflected by the back of the water drops. As this reflected light is leaving the water, it’s refracted again at several angles.
Rainbows appear when sunlight gets scattered by water droplets. The light rays pass into the drops and then get reflected back out, causing the sunlight’s wavelengths to split up into an array of colors.
A rainbow is a multicolored arc, or curved line, in the sky. Most rainbows form when the sun’s rays strike raindrops falling from faraway rain clouds. Rainbows appear in the part of the sky opposite the sun, usually in the early morning or late afternoon. From inside to outside, the colors of a rainbow are violet, indigo, blue, green, yellow, orange, and red.
Rainbows have fascinated humans for centuries. In the Book of Genesis, a rainbow appears after the worldwide flood to show God’s mercy. In Germanic mythology, there’s a rainbow bridge connecting Earth to the realm of the gods. In Ireland, a common legend asserts that a “pot of gold” is to be found at the end of a rainbow, for the person lucky enough to find it. This treasure is, however, guarded by a Leprechaun.
The most familiar type rainbow is produced when sunlight strikes raindrops in front of a viewer at a precise angle (42 degrees). Rainbows can also be viewed around fog, sea spray, or waterfalls.
Rainbows are actually full circles. The anti-solar point is the center of the circle. Viewers in aircraft can sometimes see these circular rainbows.
Viewers on the ground can only see the light reflected by raindrops above the horizon. Because each person’s horizon is a little different, no one actually sees a full rainbow from the ground. In fact, no one sees the same rainbow—each person has a different anti-solar point, each person has a different horizon. Someone who appears below or near the “end” of a rainbow to one viewer will see another rainbow, extending from his or her own horizon.
Enjoy the beauty of Boundary County and its colorful rainbows!