Free Astronomy Magazine March-April 2023

9 MARCH-APRIL 2023 ASTRO PUBLISHING L ight pollution is the improper or excessive use of artificial light. It can have serious envi- ronmental consequences for humans, wildlife, and vegetation, and it hampers astronomy. The components of light pol- lution include: 1) Glare: excessive brightness causing visual discom- fort; 2) Skyglow: clear- ing of the night sky above inhabited areas; 3) Light scattering: light falling where it is not expected or needed; 4) Clutter: bright, confus- ing, and excessive groupings of light sources. [International Dark-Sky Association] The skyglow problem is no less seri- ous than the pollution of the air we breathe or the plastic that accu- mulates in the seas and ends up in the food chain. All the great civiliza- tions of the past have developed thanks to the vision of the celestial vault and the cycli- cal phenomena it shows. Agriculture, herding, naviga- tion, and several other human activi- ties have benefited greatly from view- ing the night sky. We would know practically nothing about the universe if we hadn’t had the opportunity, until now, to ob- serve it and to ana- lyze the light that comes from every- thing in it. The stars have helped shape human culture for thousands of years. E mblematic image of what many ama- teur astronomers must face today to observe the starry sky. More and more often, even climbing high mountains is not enough. [Martin Podzorny] that if the skyglow continues to in- crease at the current rate, a child born in a place where there are 250 stars will be able to see no more than 100 on his/her 18 th birthday and will not see any more before reaching middle age. Thanks to their method, the researchers found that the growth rate of skyglow is much more sustained than previously predicted based on ob- servations in the 500-900 nanometer range, which provide average annual increases of about 2%. The global average in- crease calculated by the team is in fact 9.6%, al- most five times faster than previously believed. The two continental areas most polluted by artificial light, North America and Europe, see annual growth of 10.4% and 6.5%, respectively. Elsewhere, Globe at Night’s network coverage is less widespread, but it is inevitable that all the more densely populated areas contribute proportionally to light up the night sky. To give an idea of how worrying the current situation is, Kyba declares