Look up: Fall, winter bring atmospheric phenomena to the sky
KALAMAZOO, Mich. — Rainbows are Earth's way of revealing a secret: White light is actually a collection of different colors.
The acronym "ROY-G-BIV" stands for the red, orange, yellow, green, blue, indigo, and violet we see when white light passes through a prism.
It's a process paralleled by cloud droplets and ice crystals suspended in the sky, especially when the sun is closer to the horizon, like at dusk or dawn or during the cold weather months.
After the Autumnal Equinox back in September, the sun's most direct rays shifted south of the Equator.
Since then, the sun has struggled to reach an altitude of 30-degrees in the sky, and won't make a comeback until spring and summer.
That low sun angle makes fall and winter the coldest time of year, but also the best time of year for spotting atmospheric phenomena that resemble rainbows.
Or perhaps, an upside-down rainbow.
That's what this circumzenithal arc looks like.
The patch of cirrus clouds in the background are composed of hexagonal ice crystals that re-directed sunlight through their flat top, then out of their prism-like sides, into a reverse rainbow.
Pretty cool, huh?
Sundogs form in a similar fashion, though the hexagonal ice crystals are tilted with their flat-side horizontally oriented in the air.
Sundogs show up to the left and right of the sun, bent to a 22-degree angle toward the observer.
They usually appear in order from red closest to the sun to blue farthest from the sun.
Then there's this kaleidoscope of colors that appeared under the sun toward the end of a mild, November day.
It's called an iredescent cloud.
Notice how the distribution of color is much more chaotic than that of the circumzenithal arc or sundog.
Instead of sunlight passing through tiny, uniform ice crystals or water droplets, it is spread out, leading to a splash of color.
All the more reason to embrace fall and winter with open arms and eyes.
Follow Meteorologist Christina Anthony on Twitter and Facebook.