Andrea Sosa

Our ancestors contemplated an inspiring night sky of science, philosophy, art … today, an estimated one third of the world’s population – including millions of children – have never seen the Milky Way. The progressive degradation of the quality of the night sky must be considered as the fundamental loss of a scientific, cultural and environmental heritage of humanity. Light pollution is caused by the excessive or inappropriate use of artificial light, and constitutes one of the most widespread forms of environmental pollution. Although the concern about light pollution arose in the astronomical field, due to the loss of sky quality that damages observations, studies have been carried out since the beginning of this century that demonstrate how light pollution also affects our health, a wildlife and ecosystems. These problems, added to the waste of energy resources, show the importance of properly regulating artificial lighting at all levels.

Astronomy is one of the sciences that most uses and promotes the development of space exploration and new technologies. Paradoxically, today some of these technological developments are turning against him: sources of light pollution in the night sky must now be added to the «mega constellations» of satellites. These constitute large conglomerates of telecommunication satellites in low-altitude orbits that would start operating at the end of 2020, and whose brightness and frequency will put astronomical observations from the Earth’s surface in great compromise.

In this talk, we will summarize the most relevant aspects of light pollution, and the different global initiatives that are being developed to preserve the darkness of the night sky.