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The dark-sky movement is a campaign to reduce light pollution. The advantages of reducing light pollution include an increased number of stars visible at night, reducing the effects of unnatural lighting on the environment, and cutting down on energy usage. Earth Hour and National Dark-Sky Week are two examples of such efforts. The movement started with professional and amateur astronomers alarmed that nocturnal skyglow from urban areas was blotting out the sight of stars. For example, the world-famous Palomar Observatory in California is threatened by sky-glow from the nearby city of Escondido and local businesses.〔(Caltech Astronomy Department )〕 For similar reasons, astronomers in Arizona helped push the governor there to veto a bill in 2012 which would have lifted a ban on illuminated billboards.〔(AZ Daily Sun: "Astronomers celebrate veto of billboard bill" )〕 Nocturnal animals can be harmed by light pollution because they are biologically evolved to be dependent on an environment with a certain amount of hours of uninterrupted daytime and nighttime. The over-illumination of the night sky is affecting these organisms (especially birds). This biological study of darkness is called scotobiology.〔http://isebindia.com/05_08/05-01-3.html International society of environmental botanists: "Scotobiology – The biology of darkness"〕 Light pollution has also been found to affect human circadian rhythms.〔http://www.darksky.org/about-ida International Dark Sky Association: About the IDA〕 The dark-sky movement encourages the use of full-cutoff fixtures that cast little or no light upward in public areas and generally to encourage communities to adopt lighting regulations. A 2011 project is to establish "dark sky oasis" in suburban areas.〔(Universe Today ) IDA Suburban Outreach Sites〕 == Skyglow == Skyglow is the illumination of the night sky or parts of it, resembling an orange "smog". It occurs from both natural and human-made sources.〔http://www.lrc.rpi.edu/programs/nlpip/lightinganswers/lightpollution/skyGlow.asp Lighting Resource Centre: "What is sky glow?".〕 Artificial skyglow is caused by the over-illumination of the sky from large city centres, shopping centres, or stadiums. It consists of light that is either emitted directly upward or reflected from the ground that is then scattered by dust and gas molecules in the atmosphere, producing a luminous background or light dome. These artificial skyglows cause the sky to be 5–10 times brighter in urban areas than a naturally dark sky that is unaffected by artificial light. Natural skyglow can come from natural light sources, such as the Sun, the Moon, the stars, or auroras. Some communities are becoming aware of this problem and are putting forth efforts to minimize the hazy, orange skyglow. A community in particular is the city of Merritt, British Columbia. An article published July 8, 2010 states that they are making minor changes to lighting in and around Merritt, such as the installment of down-cast lighting to commercial buildings, as part of their light pollution abatement program.〔http://www.merrittnews.net/article/20100708/MERRITT0101/100709954/-1/MERRITT/sky-glow-burning-out Merritt News: "Sky glow burning out?" author: Kaleena Loehr〕 The benefits of this technological change include "saving energy through better focused lights, preserving the environment by reducing excess light that may affect flora and fauna, reducing crime and increasing safety by more adequately illuminating areas, and reducing health risks."〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Dark-sky movement」の詳細全文を読む スポンサード リンク
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