Strange Moonlight

[icymist]

Sept. 28, 2006: Not so long ago, before electric lights, farmers relied on moonlight to harvest autumn crops. With everything ripening at once, there was too much work to to do to stop at sundown. A bright full moon—a "Harvest Moon"—allowed work to continue into the night.

The moonlight was welcome, but as any farmer could tell you, it was strange stuff. How so? See for yourself. The Harvest Moon of 2006 rises on October 6th, and if you pay attention, you may notice a few puzzling things:

1. Moonlight steals color from whatever it touches. Regard a rose. In full moonlight, the flower is brightly lit and even casts a shadow, but the red is gone, replaced by shades of gray. In fact, the whole landscape is that way. It's a bit like seeing the world through an old black and white TV set.

"Moon gardens" turn this 1950s-quality of moonlight to advantage. White or silver flowers that bloom at night are both fragrant and vivid beneath a full moon. Favorites include Four-O'clocks, Moonflower Vines, Angel's Trumpets—but seldom red roses.

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[hvn_nbr_2]

1. That loss of color in moonlight is because of how the human eye works.

Rods and cones--I don't remember which is which, but one sees color and the other sees black and white factors such as shapes, lines, brightness, etc. The ones that see color need more light, so the dimmer the light, the more b&w the perception.

[Ilsa]

2. Rods see black and white, cones see color.

I think there are "hypercolumns" of receptors in the occiptal lobe of the brain responsible for noting shapes, IIRC.

[hvn_nbr_2]

3. You're right.

Well, I don't know enough details to know about hypercolumns, but it makes sense that shapes, lines, and such are interpreted in the brain. Rods and cones are roughly analogous to pixels, so they don't perceive more complex entities such as shapes.