Ars Technica reports on the ongoing blotting out of the stars at night, with artificial light pollution doubling in the last 10 years alone. There are ways, however, to bring the stars back to the sky we (and plenty of migrating animals) see at night:
Migratory animals, including birds and insects, are drawn away from their natural flight paths by the beckoning “sky glow” of cities. In the summer of 2019, Las Vegas was invaded by millions of migrating grasshoppers, while the beams of New York’s 9/11 Tribute in Light are a magnet for flocks of migrating songbirds flying at night.
Disoriented by the bright city lights, birds crash into towering skyscrapers. Insect numbers are collapsing worldwide and light pollution is making matters worse by disrupting their nocturnal life cycles.
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Light pollution also affects our ability to study the universe. Even modern observatories, built on remote mountaintops, are affected by the encroaching sky glow from growing, sprawling cities. Light pollution is so widespread that three-quarters of all observatories are affected.
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Fighting light pollution begins at home. If you need to keep outside lights on for security, use shielded lamps that only shine downward. Use light bulbs that do not emit violet and blue light as this is harmful to wildlife. Smart lighting controls will also help reduce your house’s effect on wildlife and make it easier for you to observe the night sky.
You will also find interactive maps that show how polluted the skies are in your area. These maps are created from data gathered by satellites and by citizen scientists taking part in annual star counts. You can help darken our skies, too.
In the UK, the 2023 annual star count will take place on February 17-24. And, wherever you are in the world, you can always take part in the year-long Globe at Night star count whenever you want.
The task is simple: step outside on a clear night, count how many stars you can see in a well-known constellation, such as Orion, and report back.
To defeat light pollution, we need to know how severe it is and what difference national policies and local interventions (such as replacing the street lights in your town) make. In the UK, for example, star counts show light pollution may have peaked in 2020 and has started to decline.
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You can take part in the Globe At Night count here.