Light pollution is rapidly gaining ground and the number of stars visible to the naked eye at night in some places could be halved in less than twenty years, according to a scientific study published Thursday in the journal. Science.
To assess the effect of artificial light on the night sky, the scientists relied on star observations made between 2011 and 2022 by some 51,000 “citizen scientists,” mostly in the United States and Europe.
The evolution of the number of reported visible stars allows us to deduce that the luminosity of the sky increased annually by 9.6% on average in the places of residence of the participants, according to the researchers. With this growth in light pollution, a place from which 250 stars could be observed would, over 18 years, see this number drop to 100.
Responsible LEDs?
This study remarkably coincided with the replacement of many exterior lights with light-emitting diodes (LEDs), but according to the researchers, the impact on the skylight of this transition to LED is unclear.
“The visibility of the stars deteriorated rapidly, despite (or perhaps because of) the use of LEDs for public lighting,” the scientists said. “Existing lighting policies do not prevent light pollution,” at least on a large scale, they say.
But light pollution goes far beyond a purely scientific aspect. “Previously, when people went out at night, they were facing the cosmos,” says Christopher Kyba, first author of the study and a physicist at the GFZ Center in Potsdam, Germany. “You go outside, you see the stars, the Milky Way…”
“And now it’s like it’s become an unusual event,” he said. “And that surely has consequences for us (…), no longer living what was almost universal.”
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Source: BFM TV
