Thursday, April 24, 2008

Lunar Light

I live in downtown DeLand, on a busy street with streetlights, it seems, every few feet (two on my small property zone alone). I've never understood why we have so many lights, generally speaking: Walking at night along a dark beach or a quiet road, I'm always struck by how little artificial light is really necessary to navigate and feel safe, especially when it's clear. My son is into stargazing, and a month or so ago we spent a new-moon night at Woodruff Preserve stargazing with the local high school astronomy teacher. It was as dark as one could imagine, but we had no navigating the alligator-infested, boggy area.

I have also noticed how street lamps, while illuminating their narrow radius, cast deep shadows at the periphery. It seems to me that outdoor lighting, which makes our eyes so less sensitive to ambient light at night, makes areas more dangerous: The perfect place to hide for a thug would be the wells of darkness beside houses and overgrown lots, taking advantage of our purblindness.

Give me full darkness any night.

Anyway, this entry's not technically on gardening, but it's Earth Day, and I often dwell here on the intertwined issues of sustainability, localism, and the need to appreciate the beauty of the world around us. Click through to read about a civil engineering idea that would change outdoor lighting for the better: "What if streetlights could respond to ambient moonlight, dimming and brightening each month as the moon cycles through its phases?...." But what was most striking was this (unsubstantiated but unsurprising) assertion:
Lunar Light: Perhaps the most fascinating fact that the collective’s research revealed, however, is a little-known detail about the history of electricity: in the 1930s, with the spread of electrification and the consolidation of utilities, streetlights became a convenient way to off-load excess energy from the grid at night, when power demands dropped significantly. This intentionally inefficient system determined the norm for nighttime outdoor lighting levels, a standard that has not been revised since, even though the need for off-loading ended in the 1970s. What we now assume is a safety measure is in fact the forgotten remnant of an obsolete energy practice. Next Gen juror Fred Dust, head of IDEO’s Smart Space design practice, says the jury found this part of the proposal both shocking and compelling. “It’s such an archaic concept that it seems like science fiction,” he says.

Questioning current lighting standards and asking what level of illumination is actually necessary brings some sur­prising answers. Willis explains that the human eye, with its com­-ple­mentary systems of rods and cones, evolved to adapt to both full-sun days and moonless nights. “We can see an incredibly broad range of intensities,” he says. “The difference between sunlight and starlight is something like a hundred thousand orders of magnitude.” Bright moonlight is in"


Anonymous said...

I just stumbled across your blog and I am intrigued by your wonderful garden. I live in Enterprise (near Deltona) and have a few things growing (tomatoes, cukes, yellow squash). I am confused about when to plant what. if you get time, could you post regarding what you plant during which season? Thanks so much! Leah

Garden Lighting said...

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