Dim the Lights, Bring on the Dark Skies

I miss daylight. It's hard to get up before the sun rises to exercise, or to leave work in the afternoon darkness. One of my favorite celebrations of the year is of the Winter Solstice, which marks, within a few days of each other, both the earliest sunset and the shortest day of the year.

But I do appreciate the seasonal rhythms of darkness and light, day and night. And I love a night sky, its vastness awash with stars or lit up by a big harvest moon. And so I was moved by Verlyn Klinkenborg's cover story in National Geographic's November issue, "The End of Night." It's not often one reads about light pollution and its effects on living things. Light is a powerful biological force, according to scientists, acting for many species as a magnet, drawing seabirds, for example, to the light from gas flares on marine oil platforms, and prompting swans to migrate earlier than is optimal for nesting. Sadly, nesting sea turtles, which prefer dark beaches, find fewer and fewer of them on which to nest. Their hatchlings, which would normally move themselves toward the brighter sea horizon are confused by artificial lighting beyond the beach and are lost by the hundreds of thousands every year.

"In most cities," Klinkenborg writes, "the sky looks as though it has been emptied of stars." New York City scores a nine on the nine-point Bortle Dark-Sky Scale, according to the International Dark Sky Association, which has pushed for city and state legislation to turn the lights down.

New York has, in fact, begun to dim down. The State Assembly passed legislation in June requiring that new outdoor lighting have shields that reduce glare and waste. Other measures -- to require full streetlight shields and motion detectors in all commercial and government buildings, and to mandate more efficiently lighted billboards - are now under consideration. The business community may be a bit ahead of the politicians on these matters. Several of the city's newest skyscrapers incorporate cutting-edge technologies that appeal to both environmentalists and those eager to keep energy costs down. Landlords have also found that meeting stiffer energy-efficiency standards in their new and refurbished buildings is a selling point with tenants, especially those that pay their own electricity bills.

For our part,

• Energy

Comments

[DougK]

I'm a life long stargazer and have extensively studied the limits of vision.

Light pollution primarily results from intentionally using lights to make it harder to see. This creates "artificial darkness" which naturally motivates desire for more lights.

Despite being easily demonstrated, most people can't recognize the fact that bright lights help vision the same way loud noises help hearing. Looking into the distance at night you clearly see lights, BUT you don't clearly see the illuminated areas surrounding those lights because of artificial darkness.

The human eye can percieve a luminance range of about 100 to 1. Since a light source is always more luminous than whatever it illuminates, artificial darkness results whenever lights aren't shaded to preclude direct sight of the lamp.

Another reason for light pollution is the huge increase of outdoor luminance per capita over the last generation. This is coincident with HPS lighting (more lumens per watt ). Brighter lights, in fixtures designed to create artificial darkness, are why outdoor light per person is now much higher than for previous generations.

Shading outdoor lights so the source can't be directly seen, from ten times the fixture height, would not only curb light pollution, it would greatly improve everybody's vision at night! Especially middle age and older people.

Such simple changes (lampshades) have been fought long and hard by those who make money building, installing, and operating lights which unnecessarily make it harder to see for the purpose of motivating demand for ever more lights.

[dogugotw]

I feel incredibly lucky to live in a place that is still dark enough that I can see the Milky Way. When we moved her a few years back, I thought I was seeing some kind of weird cloud. After about 3 nights, it dawned on me that the cloud never moved and I realized it was stars...LO­TS of stars.

Wiinter is here and the nights are awesome!