Polarized light pollution
Encyclopedia
Light pollution
Light pollution, also known as photopollution or luminous pollution, is excessive or obtrusive artificial light.The International Dark-Sky Association defines light pollution as:...
referring specifically to polarized light.
In nature, water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
and water vapor
Water vapor
Water vapor or water vapour , also aqueous vapor, is the gas phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Under typical atmospheric conditions, water vapor is continuously...
polarize the sunlight
Sunlight
Sunlight, in the broad sense, is the total frequency spectrum of electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the Earth's atmosphere, and solar radiation is obvious as daylight when the Sun is above the horizon.When the direct solar radiation is not blocked...
(which itself is slightly polarized). By receiving the direction of polarized photons, some species can correct their course during migration
Animal migration
Animal migration is the relatively long-distance movement of individuals, usually on a seasonal basis. It is a ubiquitous phenomenon, found in all major animal groups, including birds, mammals, fish, reptiles, amphibians, insects, and crustaceans. The trigger for the migration may be local...
). Artificial polarization of natural or artificial light can disrupt the behavior of these species and the ecosystems in which these species play an important role. Pollination
Pollinator
A pollinator is the biotic agent that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization or syngamy of the female gamete in the ovule of the flower by the male gamete from the pollen grain...
is one example of this.
History of this notion
Jean-Baptiste BiotJean-Baptiste Biot
Jean-Baptiste Biot was a French physicist, astronomer, and mathematician who established the reality of meteorites, made an early balloon flight, and studied the polarization of light.- Biography :...
and his successors have shown that solutions of organic products, such as fructose
Fructose
Fructose, or fruit sugar, is a simple monosaccharide found in many plants. It is one of the three dietary monosaccharides, along with glucose and galactose, that are absorbed directly into the bloodstream during digestion. Fructose was discovered by French chemist Augustin-Pierre Dubrunfaut in 1847...
or sucrose
Sucrose
Sucrose is the organic compound commonly known as table sugar and sometimes called saccharose. A white, odorless, crystalline powder with a sweet taste, it is best known for its role in human nutrition. The molecule is a disaccharide composed of glucose and fructose with the molecular formula...
, can polarize light. However, only in recent decades has it been realised that the polarized light may play an important role in ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
s, especially in the insect world.
More recently, when the concept of light pollution
Light pollution
Light pollution, also known as photopollution or luminous pollution, is excessive or obtrusive artificial light.The International Dark-Sky Association defines light pollution as:...
emerged, the question of the possible impacts of the artificial polarization of light has arisen.
Gábor Horváth and his team have proposed that this new term needs to be better described and understood in order to better address the specific ecological consequences (direct or delayed in space and time) of light that was polarized (at source or by interacting with objects made or modified by humans).
External links
Related organizations
Research about light pollution
- The Challenge article "Is Light Pollution Killing Our Birds"
- The Discover article relating light pollution to insects, birds, and breast cancer (requires paid registration)
- Ecology of the night symposium (2003 conference)
- "Ecological Consequences of Artificial Night Lighting" (2002 conference, by the Urban Wildlands Group)
- Light pollution and the protection of the night environment, UNESCO, IDA Regional Meeting, 360 pages,(2002) English — Italian. Proceedings are available as a downloadable PDF.
- Sherbrooke College Light pollution research activities
- http://www.fraserf.id.au/astronomy/martin-lewicki/lpgallry.htm Examples of the good, bad and ugly lighting
- "Our Vanishing Night", Verlyn Klinkenborg. National Geographic, November 2008, pp102–23.
- "Blinded by the Light?", CfDS 2009, Various authors discussing the "hidden" environmental harm, the human health harm, the money waste, lighting failing to prevent crime and even astronomy.
Collections of links related to light pollution
- Dark Sky Awareness global project
- BAA CfDS Discussion Forum
- Dark Sky Importance gallery at The World at Night
- The Dark Side: an article in The New Yorker magazine about light pollution
- Reclaiming the Night Sky, article by Judith Dobrzynski from The New Republic on light pollution
- Astronomical Society of South Australia article on Light Pollution in Adelaide, South Australia
- Good Bad and Ugly Outdoor Lighting and update Adelaide South Australia
- Turn Out the Lights!
- ALI - the Alliance for Lighting Information - website contains information about light, lighting and related topics.
- Verlyn Klinkenborg: "Our vanishing night" National Geographic November 2008 link
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