Skyglow - The Hindu - 25/01/23

Context:
Recently, a new study has found that non-natural light had increased the brightness of Skyglow, by 9.2-10% every year between 2011 and 2022 with significant ecological, health and cultural implications. Researchers have analyzed a global database of what the dimmest star visible from a particular location is; the database had more than 51,000 entries submitted by citizen scientists.
Relevance:
GS3
About:
->Skyglow:
- The Skyglow, is an omnipresent sheet of light across the night sky in and around cities that can block all but the very brightest stars from view. The brightening of the night sky over inhabited areas because of streetlights, security floodlights and outdoor ornamental lights cause the Skyglow.
- 'Skyglow' is one of the components of light pollution.

-> Global Scenario
-The Skyglow had brightened around 6.5% over Europe, 10.4% over North America, and 7.7% over the rest of the world. The finding is significant because it disagrees with satellite-based data, which has indicated that the rate of increase has been around 2% per year.

->Indian Scenario
-A 2016 study reported that 19.5% of India’s population – the lowest fraction among G20 countries – experiences a level of skyglow that would at least keep the Milky Way galaxy out of sight and at most render “dark adaptation for human eyes” impossible. The effects include stimulating the cone cells in human eyes, which is possible only when an environment is considered to be well-lit.

->Implications of Skyglow?
a. Wastes Energy and Money
b. Disrupting the Ecosystem and Wildlife
c. Harming human health

->Solutions:
-The researchers recommend light sources casting light at an angle below the plane of the horizon, capping the emissions of these sources and calibrating their output according to the total brightness at the spot being lit.
-Where lights cannot be turned off, they can be shielded so that they do not shed light into the surrounding environment and sky.

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