light pollution

Space debris and satellites orbiting close to Earth have proliferated in recent years. Two articles in Nature Astronomy warn of their impact on light pollution. In the first, a team calculates the increase in the brightness of the night sky and warns of the effect on ecosystems and astronomical observations from Earth. In the second, which is a commentary, the authors call for limiting the production of artificial light and the number of satellites in orbit, calling on the scientific community to take on the big space and big light companies. Both articles are co-signed by Salvador Bará, from the Agrupación Astronómica Coruñesa, and the second by Fabio Falchi, from the University of Santiago de Compostela.

The brightness of the night sky has increased by 7 to 10 % per year (depending on the region of the world) in the range visible to the human eye, according to an analysis based on 51,000 observations made with the naked eye by citizen scientists between 2011 and 2022. According to the research, published in Science, this increase is faster than what can be observed with satellites; satellites cannot detect blue emissions from LED lights, which are increasingly used in street lighting.

Using images taken by astronauts aboard the International Space Station, a team of researchers has designed a map showing the variation in the spectral composition of artificial lighting across Europe during 2012-2013 and 2014-2020. The results, published in the journal Science Advances, show a change associated with white LED lights and higher blue emissions, which the authors link to an increased risk of harmful effects on ecosystems.