Double rainbows seen over Caloosahatchee River in recent days; pots of gold a rumor

“All the best things in life are free: love, smiles, friends, family, pets & companions, thoughts, sunsets & sunrises and especially rainbows.”

― Anthony T. Hincks

Double rainbows have been spotted at least twice during the last several days in nearly the same spot over the Caloosahatchee River, either ending or starting at the Interstate 75 bridge depending on the point of view.

No pots of gold were reported.

The ingredients for rainbows are sunlight and raindrops.

The optical phenomenon occurs when sunlight passes through raindrops, which are comprised of many colors even though rain looks white or clear to the human eye.

Tom Bayles

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WGCU

As sunlight enters a raindrop it slows down and each color in sunlight bends by a slightly different amount because they have different wavelengths.

The light reflects off the inner surface of the raindrop, causing the light to bend in another direction. When the light exits the raindrop, it’s spread out into its individual colors. This separation of colors is called dispersion.

That’s when a rainbow becomes visible to the human eye. We can see a rainbow because these separated colors form a circular arc in the sky, with red on the outer part and violet on the inner part.

A double rainbow occurs when the light is reflected twice in the drop. It means you can see two different reflections, each coming from different angles.

This leads to something that is nearly as magical as a rainbow itself: instead of seeing red at the top and blue at the bottom like a regular ho-hum rainbow, the secondary rainbow, which is higher and lighter in color than the primary rainbow, has the colors reversed.

What’s really neat is there are rainbows in wavelengths we can’t detect. A quadruple rainbow could be right in the sky above the Caloosahatchee River and we wouldn’t know.

There are twinned rainbows, supernumerary rainbows, red rainbows, a moonbow, a fog bows, reflected and reflection rainbows, and even sleetbows.

There are also higher-order rainbows, most often made in a lab, that have incredible configurations not visible to us, like a 200th-order rainbow created by a method including an argon ion laser beam, according to the “Journal of the Optical Society of America B.”

Environmental reporting for WGCU is funded in part by VoLo Foundation, a non-profit with a mission to accelerate change and global impact by supporting science-based climate solutions, enhancing education, and improving health. 

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