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6. These four categories of light pollution are used (although with slightly different terms) by the International Dark-Sky Association, and cited elsewhere as well (e.g. Morgan-Taylor, 2014 Morgan-Taylor, M. (2014). Regulating light pollution in Europe: Legal challenges and ways forward. In J. Meier, U. Hasenöhrl, K. Krause, & M. Pottharst (Eds.), Urban lighting, light pollution and society (pp. 159–176). New York, NY: Taylor & Francis. [Google Scholar]). As such, I am accepting these as the standard causes of light pollution. For more information on how to get involved, you can contact the IDA directly. (And to learn more about light pollution, you can also watch “Losing the Dark,” a short planetarium show and video on light pollution produced by the IDA.) The challenge faced by 21st century policymakers is to provide outdoor light where and when it is needed while reducing costs, improving visibility, and minimizing any adverse effects on plants, animals, and humans caused through exposure to unnatural levels of light at night. (Kyba et al., 2014 Kyba, C., Hänel, A., & Hölker, F. (2014). Redefining efficiency for outdoor lighting. Energy & Environmental Science, 7, 1806–1809.10.1039/C4EE00566J[Crossref], [Web of Science ®] [Google Scholar], p. 1807) Some studies suggest a link between exposure to light at night, such as working the night shift, to some types of cancer, diabetes, heart disease, and obesity. That’s not proof that nighttime light exposure causes these conditions; nor is it clear why it could be bad for us. But we do know that exposure to light suppresses the secretion of melatonin, a hormone that influences circadian rhythms, and there’s some experimental evidence (it’s very preliminary) that lower melatonin levels might explain the association with cancer. I dropped my camera and the red light wont go away i did change the batteries Humphreys, D. R. 1994. Starlight and time. Green Forest, Arkansas: Master Books. Senator Bernie Sanders took the spotlight Monday in a live-streamed town hall focused on inequality. The event came a couple of days after an op-ed in The Guardian in which he criticized “corporate media” for ignoring the rise of oligarchy in the US. In another study of blue light, researchers at the University of Toronto compared the melatonin levels of people exposed to bright indoor light who were wearing blue-light–blocking goggles to people exposed to regular dim light without wearing goggles. The fact that the levels of the hormone were about the same in the two groups strengthens the hypothesis that blue light is a potent suppressor of melatonin. It also suggests that shift workers and night owls could perhaps protect themselves if they wore eyewear that blocks blue light. Inexpensive sunglasses with orange-tinted lenses block blue light, but they also block other colors, so they’re not suitable for use indoors at night. Glasses that block out only blue light can cost up to $80. Determine the frequency of … (GIVEN: 1 m = 109 nm) a. … red visible light (λ = 650 nm) b. … violet visible light (λ = 420 nm) So while the fascination and allure of illuminations persist, darkness is today increasingly perceived as a rare and valuable commodity. This development could be regarded as a double paradigm shift from the dark night as a forbidding everyday occurrence that could only be lit up sporadically to its devaluation as an emblem of backwardness in the face of a new abundance of artificial light in the late 19th and early 20th centuries to its present valorization as a sought-after luxury in our densely populated and highly electrified world. (Hasenöhrl, 2014 Hasenöhrl, U. (2014). Lighting conflicts from a historical perspective. In J. Meier, U. Hasenöhrl, K. Krause, & M. Pottharst (Eds.), Urban lighting, light pollution, and society (pp. 105–124). New York, NY: Taylor & Francis. [Google Scholar], p. 119) Current calls for mitigation are often rested on an appeal to needs. For example, the International Dark-Sky Association cites needs-based principles of lighting as a way to minimize the negative effects of light pollution (IDA, 2014 IDA. (2014). International Dark-Sky Association. International Dark-Sky Association. Retrieved 15 January, 2015, from [Google Scholar]). It seems to follow that ‘unneeded’ nighttime illumination equates to light pollution, and therefore, contributes to the pre-defined negative effects. For, at the least, lighting deemed unnecessary wastes energy. This requires a clear justification for what is ‘needed’ nighttime illumination, which is both a quantitative and qualitative question. However, the moral terrain of such claims has been left largely unexplored. A needs-based approach requires that we can confidently point to criteria for needed lighting. Yet, as historic surveys on nighttime lighting makes clear, the blurring of symbolic and actual needs of nighttime lighting are complex at best, and needs are co-constituted by societal perceptions and values (Nye, 1990 Nye, D. E. (1990). Electrifying America: Social meanings of a new technology, 1880–1940. Cambridge: MIT Press. [Google Scholar]; Schivelbusch, 1988 Schivelbusch, W. (1988). Disenchanted night: The industrialization of light in the nineteenth century. (A. Davis, Trans.) London: University of California Press. [Google Scholar]). If policies aimed at light pollution mitigation adopt a needs-based approach, adequate reasoning should be given for why a different approach—say one geared toward preferences and desires—is insufficient. Attaching the language and connotations of pollution to nighttime lighting is effective, but may also set boundaries on possible solutions. This is a very specific answer to the question of how much light is appropriate, which comes with limitations. As a moral concept, light pollution can tell us what bad lighting is, but says relatively little about what good lighting is. Because of the focus on the (adverse) causes and effects of artificial nighttime lighting, the concept is limited in its capacity to inform choices within the realm good lighting, especially in cities where there are other values at play. Light pollution says very little about artificial nighttime illumination deemed to be within the acceptable limits of polluting, or the many values and needs strived for therein (for example, esthetics and nightlife). Thus, there are limits to the capacity of light pollution to inform moral evaluations, as it frames decisions as questions about acceptable levels of polluting. The 350 year project of illuminating our nights has produced a challenging situation. The desire for more and better lighting at night has left us with an overabundance of artificial illumination, and has produced a novel problem. The realization of lengthening the day is increasingly perceived as a loss of the night, and a new frame has emerged to give shape to these concerns. The story of light pollution goes back much further than the 1970s, in juxtaposition but nevertheless linked to the technical and social history of modern nighttime illumination. Importantly, the concept of light pollution re-frames certain aspects and uses of nighttime lighting technologies. If we return once more to the driving question (how much artificial light at night is appropriate?), we can appreciate that the concept of light pollution provides a new starting point, and not an end point, for discussions about the future of nighttime lighting.1010. I would like to thank the anonymous reviewer for this insight.View all notes Such a question may not strike you as entirely novel or revolutionary, as surely such questions are as old as attempts to illuminate our nights. But, the context in which this question is posed—the growing recognition of environmental and health-related problems caused or amplified by nighttime lighting—gives it new meaning. We are now seeking a transition in nighttime lighting strategies toward reducing the amount of illumination. And, it has been acknowledged that traditional approaches have been ineffective to date. Kyba, Hänel, and Hölker (2014 Kyba, C., Hänel, A., & Hölker, F. (2014). Redefining efficiency for outdoor lighting. Energy & Environmental Science, 7, 1806–1809.10.1039/C4EE00566J[Crossref], [Web of Science ®] [Google Scholar]) note that despite improvements to efficiency in lighting technologies, energy usage for outdoor lighting and artificial nighttime brightness continues to increase annually. Thus, a complete conversion to efficient lighting technologies alone (i.e. LEDs) is unlikely to reduce energy consumption or other unwanted consequences; new approaches to nighttime lighting must look beyond the narrow focus of improving efficiency. They summarize this necessary change in perspective by stating that, deseo machoman eracto Eron Plus Maxman Atlant Gel testogen Zevs TestX Core Erozon Max