Skyglow

Why in News?

•  Recently,  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.

Highlights

• 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.
• This light floods directly into the eyes of the Nocturnal (active at night) and also into the skies and misleads their path.
• ‘Skyglow’ is one of the components of light pollution.
• 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.
• 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.
• The discrepancy Is probably the result of the satellites being unable to ‘sense’ blue light emitted by LEDs and to study light that is emitted parallel to the ground.
• 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.
• The International Dark-Skies Association has certified more than 130 ‘International Dark Sky Places’, where artificial lighting has been adjusted to reduce skyglow and light trespass. However, nearly all are in developed countries in the northern hemisphere.
• Less-developed regions are often both species-rich and, currently, less light-polluted, presenting an opportunity to invest in lighting solutions before animals there are seriously affected.