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Nowadays, we have engineered the night to receive us by filling it with light. Nevertheless, this engineering comes with serious consequence, that is, light pollution, also known as phytoplankton or luminous pollution. This is a form of environmental degradation, which results from the excessive artificial lightings. Its sources include street lamps, neon signs, billboards, offices, and illuminated sporting venues.
Instead of directly lightening objects, these artificial beams refract and scatter around everywhere unexpectedly. Hence, they not only obscure the starring night but cause damage to both our environment and human bodies. Therefore, light pollution is not even more a scientific issue to experts but a global problem to everyone. According to the International Dark-Sky Association (IDA), this environmental pollution can be classified into four types: light trespass, over- illumination, glare, and light clutter. The first type is light trespass, which occurs as unnecessary light enters one’s property.
When an intense beam outside causes sleep deprivation, this condition can be called light trespass. For instance, Hong Kong has a serious light trespass problem due to countless luminous ornaments of skyscrapers. Despite some 30 to 40 citizens annually complaints about light abuse, Hong Kong still ignites the night sky to demonstrate its prosperity. The second type is over-illumination, which stems from the excessive waste of light. Improper lighting designs in the workplace, inadequate lighting maintenance, and 24-hour commercial advertisements all contribute to over-illumination.
A survey conducted by the U. S. Department of Energy Source suggests that some 30 to 60 percent of energy is wasted by commercial advertising uses, two times than average U. S. Residential consumption. The third type is glare, which can be further divided into three classifications. First, blind glare describes an effect caused by staring into the Sun, leading to completely blinding and temporary or permanent vision deficiencies. Second, disability glare leaves significant reduction in Sight abilities by oncoming vehicle beams, or refracted glow in the fog as well as reflections from the printed.
Third, the discomfort glare dose doesn’t induce a dangerous situation, though it is irritating at best. The last type is light clutter, excessive groupings of lights. Clutter may generate confusion, distract from obstacles, and potentially induce accidents. For instance, the poor-designed street lights distract drivers and cause injuries. Besides, clutter may present a hazard, specifically in aviation environment. For instance, aircraft collision avoidance signals may be confused with grouping commercial lightings.
Intriguingly, few know that light, a powerful biological force, influences not only human but both plants and animals as well. Plants acquire light not only for energy supply but for the induction of flowering. Each species has its specific ecological optimum curve, which describes the relationship between light intensity and growth. Outdoor lightings on plants result in abnormal individuals with delayed loss of leaves or accelerated branch growth. To the plants near street lights, they even have production in second bloom in autumn.
Similarly, light pollution induces adverse effects on animals. It may disorient animals and disrupt their biological rhythms, which are related to the alternation of day and nights of the seasons. As National Geographic Magazine mentions, fewer and fewer of nesting sea turtles, which show a natural predisposition in the dark, lay eggs on sandy beaches. Their hatchings, which gravitate toward the more reflective sea horizon, find themselves confused by artificial lighting behind the beach. In England, some swans even put on fat more rapidly than usual for wintering and migrate to
Siberian early. Since long artificial days induce early breeding, a wide range of birds shuffle their migration schedules. Under the long- term influence of light pollution, nocturnal mammals including desert rodents, fruit bats, opossums, and badgers forage more cautiously because they have become easier targets for predators. As for other creatures, we also have a genetically light-determined clock to control the day-night rhythm in the secretion of melatonin, which in turn affects the sleeping-waking rhythm, the movement rhythm and our brain activities.
Disturbances in the day-night rhythm can have physical and psychological effects, such as jet-leg. Overall, changes in light level are like the alteration of gravity. It destroys the balance in our ecosystem. Since light pollution triggers serious environmental problem, issues on how to reduce it become vital and are discussed radically. The Hong Kong Night Sky Brightness Moon tutoring Network (INS) considers the rule of thumb for reducing light pollution is using lighting reasonably: do not set up unnecessary lighting and turn off lights which are not in use.
Simply turning if the light when we leave a room can achieve the target. Other approaches include reducing as many useless outdoor lighting as possible, modifying the existing lightings into dark-sky friendly devices, and choosing astronomical- friendly lighting sources. For government and organizations, turning off the neon signboards at midnight, and reducing decorative lights of commercial buildings are all possible approaches. Take Japan as a demonstration. In 1996, Ministry’ of the Environment guided Japanese to turn off all lightings during the coming of comet Haystack.
Besides, saving energy and reducing eight pollution can both be achieved by turning off useless lightings. The “Earth Hour” campaign in Sydney, for example, successfully assembles two millions people to turn off their lightings for an hour at night. It not only results in 10. 2% of reduction in energy consumption but promotes the message of preventing global warming at the same time. With efforts spreading around the globe recently, more and more cities and even entire countries have committed themselves to reducing light pollution. To sum up, light abuse not only induces problems for astronomers but impacts our daily lives.
Living in our own making glare, we cut ourselves off from the light of the stars, disrupt the biological rhythms of day and night, and harm the ecosystem. What’s worse, we gradually neglect the treasure that heaven offers at night- the astonishing galaxies arching ahead. In a very real sense, light pollution causes us to lose sight of our true place in the universe and to forget the scale of our being. While our planet will likely never return to its natural state of darkness, we still can make efforts to help decrease over-illumination.