Artificial Light Threatens 1 of Earth’s 6 Darkest Observatory Sites in Chile’s Atacama
Updated
Updated · BBC.com · May 29
Artificial Light Threatens 1 of Earth’s 6 Darkest Observatory Sites in Chile’s Atacama
1 articles · Updated · BBC.com · May 29
Paranal in Chile’s Atacama Desert—one of only six professional observatory sites with light contamination below 1%—is facing worsening skyglow that astronomers say could undermine world-class observations.
A 2025 European Southern Observatory analysis found the proposed Inna industrial complex could have raised light pollution above some telescopes by as much as 50%, even though developer AES Andes later dropped the project in early 2026.
Researchers say the broader threat remains because light from Antofagasta, mining and energy facilities is already creeping closer, while Chilean rules still rely on a 1970s threshold allowing up to 10% extra sky brightness.
That limit is too lax for Paranal, astronomers argue, because even a 1% increase harms a site hosting the Very Large Telescope and the 39m Extremely Large Telescope due to finish in 2027.
The fight mirrors a global trend: about 80% of people now live under light-polluted skies, and one study found night-sky brightness rose nearly 10% a year worldwide from 2011 to 2022.
If light pollution is reversible, what stops us from reclaiming the night sky for science and nature?
Beyond astronomy, how is the global loss of darkness impacting the health of our planet and ourselves?
As Chile fights city lights, will a million new satellites make the war for dark skies unwinnable?
After INNA: Chile’s Urgent Battle to Protect the World’s Largest Astronomical Hub from Light Pollution
Overview
The cancellation of the INNA project in January 2026 marked a major victory for protecting dark skies and preserving astronomical research in northern Chile. The project, which threatened the exceptional darkness around the Paranal Observatory, would have caused significant light pollution and other disturbances. This outcome was achieved through strong advocacy from scientists, environmental groups, and the public, highlighting the urgent need for robust protection measures around observatories. However, experts warn that this success does not mean the work is finished, as ongoing efforts are needed to safeguard these vital skies for future discoveries.