The sky is blue for many “reasons.”

Reason is an “intellectual faculty that adopts actions to ends.”

The left brain says, “I’m late, I’m late, for a very important date.”

The right brain says, “If you don’t care where you’re going, you ain’t lost.”

One of the million reasons the sky is blue is to TIME life on planet Earth.

Scientists say blue light and circadian rhythms co-evolved because life began in the sea.

Close, but no cigar.

Life began on land, not in the ocean.

But it’s true that meat began in the ocean.

The sodium in the ocean provided the flexibility to transform inflexible plant matter into flexible animal matter.

Blue light and circadian rhythms upgraded their relationship after life became flexible in the sea.

Rhythm and blues got funkier in the “seven seas” (actually, an octave).

One definition of “alertness” is a 300 millisecond response, cultivated by 459-484 nanometer light spectra.

In other words, “alertness” is the blink of an eye, assisted by blue light.

Our eyes and brain are especially sensitive to the color blue.

The “school teacher” answer to, “Why is the sky blue?” is …

“It’s caused by diffuse sky radiation.”

Their answer to, “Why is a blue eye blue?” is …

“It’s reflecting blue light.”

Their answer to, “Why do some monkeys have blue buttocks?” is …

“Those monkey butts are reflecting blue light.”

Sherwin-Williams has nothing to do with the blue sky, blue eyes, or blue monkey butts.

John Naylor (Out of the Blue: A 24-Hour Skywatcher’s Guide, 2002) wrote …

“The sky looks blue because sunlight is scattered by molecules in the atmosphere. A molecule scatters about ten times as much blue light as it does red light. Consequently scattered sunlight, called airlight, contains far more blue light than unscattered sunlight. At the same time, forward-scattered light is deficient in blue light. In other words the proportion of red light to blue light is greater than in unscattered sunlight. From a direction perpendicular to the Sun’s rays airlight looks blue, whereas looking towards the Sun the sky looks less blue.”
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