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| Source: 1920x1080 Resolution Forest Milky Way Night Reflection over River 1080P Laptop Full HD Wallpaper - Wallpapers Den |
The night sky used to be pure wonder. A person would gaze upwards on a clear night and see a huge spectacle of stars and the soft glow of the brushstroke that is the Milky-Way. The night was the pure opposite of day, it held safety for nocturnal animals and provided a respite for the species that spent their energy during the day. What do you see when you go outside at night now? How many stars do you see? Is it thousands? Hundreds? A couple dozen? It is most certainly not the same night sky that your ancestors looked at hundreds of years ago. What you probably see is only a smattering of the brightest stars and the glow of the nearest cities on the horizon. The night has lost its darkness. Light Pollution is to blame, which is defined as "a broad-scale phenomenon, with hundreds of thousands of light sources cumulatively contributing to increased nighttime illumination of the sky". As the earth lights up at night, it becomes more and more difficult to see the stars and experience natural darkness on our planet. The Earth's atmosphere reflects back the terrestrial light sources, creating an effect called sky-glow, which outcompetes the light from the stars and moon.
Light pollution is an issue that only grows worse; it is estimated that every year it expands by 3-6%. In 2016, 1/3 of the Earth's population was unable to view the Milky Way; 3/5 Europeans and 4/5 North Americans cannot see the Milky Way when they step outside of their homes. The proliferation of light pollution has been driven by affordability of new lighting and development of technologies that allow lights to be brighter. As lights became cheaper, paradoxically the consumption and abundance increased exponentially, so that the potential savings of affordable technologies was never realized; this demonstrates an economic trend called Jevon's Paradox. The newer cheaper lights (LEDS) emit blue-light wavelengths, which is reflected in our atmosphere more readily than other wavelengths and thus increases the amount of sky-glow at night.
For a long time, the only complaints regarding light pollution were regarding difficulties with astronomical observations and night-time ascetics. Scientists viewing celestial bodies and looking to understand outer space were having a tougher time making their observations. People around the globe noticed that the night sky was brighter and less beautiful to regard. However, as time went on and the night sky continued to brighten, more effects became apparent that were more worrisome. Nocturnal animals found less safety in the night then they were accustomed to. Sleep cycles were disturbed and species were out when they should have been safely hidden in their burrows or dens. Soon, it was found that ecosystems and biological processes worldwide were under threat of being significantly disturbed by the loss of natural darkness.
