Free Astronomy Magazine March-April 2023

5 MARCH-APRIL 2023 ASTRO PUBLISHING sodium and mercury vapor lamps, gave hope that the negative trend of light pollution could at least be slowed down, but this did not hap- pen. Although the global LED mar- ket share for outdoor lighting in- creased from less than 1% in 2011 to 47% in 2019 (66% in 2020 in the USA, where the problem is more pressing), skyglow has steadily in- creased. It is unclear whether the transition to LEDs has had and con- tinues to have a direct impact on in- creasing skyglow. It has certainly not mitigated the problem, just as the various national and international policies to contain artificial lighting, in defense of the natural rhythms of humans, animals and plants, have not mitigated it. But there is more. A study recently published in Science shows that skyglow is increasing much faster than expected based on observational data acquired from satellites. The first author of the study is the physicist Christopher Kyba (GFZ German Research Center for Geosciences, Potsdam) who, with his colleagues, had the idea of com- bining satellite data over the last P eople all over the world are seeing fewer and fewer stars in the night sky. The deterioration in star visibility can be explained by an increase in sky brightness of up to 10% per year. The rate of change is faster than satellite measurements of artificial light emissions on Earth initially suggested. [NOIRLab]