Before bed, I take our rather large dog for her nighttime walk so there will be no “accidents.” I am old and weigh 300 lbs., so I take the direct route, along the driveway. There are margins of grass and weeds on either side.
In late summer, for about the past several years, I have seen these tiny lights glow, then fade, glow then fade. When I first spotted them, I hustled back to get a flashlight so I could see what the little accordion-like creatures. Turns out they were glowworms.
Sing with Me Now
Of course the song Glow Little Glow Worm by the Mills Brothers came immediately to mind. But imagine my surprise when, one night in mid-spring I saw a different glow. What was this glow? Bending down, I realized it was a small clump of Buttercups. Buttercups glow at night?
Ah, You Do Love Butter
I wondered at this. “Is there some sort of phosphorescence going on here?” The answer is: No. But something else, something very real was going on. It was not my imagination. Even during daytime, the buttercup has become proverbial. Why, it glows — especially if you like butter. What gives?
Buttercups Glow – The Science
There are three basic reasons for the rich yellow glow of the buttercup, Cambridge University informs us. First, the flower absorbs blue-green light, but not yellow, allowing that to bounce back—along with much of the ultraviolet light. Second, the outer or epidermal cells of the buttercup are flat, acting like mirrors, throwing the light “back at you”. Third, there is an air gap beneath the epidermis but above the starch layer that reflects yet more light.
So how does the buttercup “glow” at night? Well, the best explanation I can give, in view of the discoveries made at Cambridge, is that buttercups reflect the limited light they receive sufficiently well so that they are “less dark” than their surroundings.
Where Should the Credit Go?
Interestingly, the U of C credits the flower for the accomplishment. This author wonders how a flower was able to achieve the feat, since it is not a sentient (or thinking) creature.- Psalm 14:1
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