GC: n

CT: For most of Earth’s history, our spectacular universe of stars and galaxies has been visible in the darkness of the night sky. From our earliest beginnings, the vast spectacle arrayed across the dark sky has inspired questions about our universe and our relation to it. The history of scientific discovery, art, literature, astronomy, navigation, exploration, philosophy, and even human curiosity itself would be diminished without our view of the stars. But today, the increasing number of people living on earth and the corresponding increase in inappropriate and unshielded outdoor lighting has resulted in light pollution—a brightening night sky that has obliterated the stars for much of the world’s population. Most people must travel far from home, away from the glow of artificial lighting, to experience the awe-inspiring expanse of the Milky Way as our ancestors once knew it.

S: DA – http://www.darkskiesawareness.org/faq-what-is-lp.php (last access: 2 December 2016)

N: 1. light (n): “brightness, radiant energy, that which makes things visible,” Old English leht, earlier leoht “light, daylight; spiritual illumination,” from Proto-Germanic *leukhtam.
pollution (n): mid-14c., “discharge of semen other than during sex,” later, “desecration, defilement” (late 14c.), from Late Latin pollutionem (nominative pollutio) “defilement,” noun of action from past participle stem of Latin polluere “to soil, defile, contaminate,” from por- “before” + -luere “smear,” from PIE root *leu- “dirt; make dirty”. Sense of “contamination of the environment” first recorded c. 1860, but not common until c. 1955.
2. Light pollution is excessive, misdirected, or obtrusive artificial (usually outdoor) light. Too much light pollution has consequences: it washes out starlight in the night sky, interferes with astronomical research, disrupts ecosystems, has adverse health effects and wastes energy.
3. The problem of light pollution is not only a menace to astronomers. People who have no interest in astronomy are affected by the intrusion of light into their properties; be it a streetlamp that shines into their bedroom or the danger caused to motorists from the glare from poorly designed/placed streetlights and floodlights. Light pollution also has numerous direct impacts on the environment. Not only can some high-powered lights produce more carbon dioxide over a year than a modern day diesel car produces in about 500 kilometres (read more) , but the strain on wildlife in both urban and rural locations is great (read more) . Light pollution is also an unnecessary waste of energy that eventually gets translated into a great and unnecessary cost to economies worldwide (read more)
4. According to “The First World Atlas of the Artificial Night Sky Brightness,” a report on global light pollution published in volume 328, issue 3 (2001) of the Monthly Notices of the Royal Astronomical Society, two-thirds of the U.S. population and more than one-half of the European population have already lost the ability to see the Milky Way with the naked eye.

S: 1. OED – http://www.etymonline.com/index.php?allowed_in_frame=0&search=light+pollution (access: 2 December 2016 ). 2. https://www.globeatnight.org/light-pollution.php (last access: 2 December 2016). 3. GN – https://www.globeatnight.org/light-pollution.php (last access: 2 December 2016). 4. PMC- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2627884/ (last access: 2 December 2016).

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CR: climate change, ecology, environment, pollution .