Astronomers Save the Darkest Skies in the World from Deadly Pollution

The energy company planned to install a 3,000-hectare green hydrogen and ammonia production plant less than 10 km from Paranal and the future Extremely Large Telescope (ELT), the largest telescope on the planet currently under construction.

According to ESO studies, the installation would have increased light pollution by more than 35%, generated atmospheric turbulence, continuous micro-vibrations, and suspended dust. Impacts that would have compromised high-precision observations.

Itziar de Gregorio-Monsalvo, ESO's representative in Chile, sums it up: 

“These harmful impacts will no longer occur. We will be able to continue operating with the most powerful telescopes on the planet.” 

The cancellation, formalized before the Environmental Assessment Service a week ago, represents “a momentary relief,” but highlights the urgency: “Chile still lacks adequate regulations to protect the quality of its skies.”

Professor Johan Fynbo (Niels Bohr Institute, University of Copenhagen), a regular user of the Very Large Telescope (VLT), emphasizes: 

“It was a green energy project, but it would have generated a lot of light pollution and dust, damaging one of the best sites in the world for astronomy.” He underscores the uniqueness of the Atacama Desert due to its dryness, altitude, and transparency: “Increasing the background light makes it much harder to see the faint light that large telescopes seek. Some discoveries, such as the first galaxies or exoplanets, would not have been possible.”

Antonia Varela, director of the Starlight Foundation and a pioneer in protecting dark skies from the Canary Islands, also celebrates but warns of the dilemma: “Our hearts are torn with renewable energies. It's clear that not everything goes, and not at any price.” 

Future Commitment

The key to success lay in the coordinated pressure from international scientists, Chilean authorities, and organizations such as the Fundación Cielos de Chile. Even so, De Gregorio-Monsalvo insists: “The protection of the skies does not end here.” ESO will collaborate to establish protection zones and modern regulations that prevent future conflicts between energy mega projects and unique astronomical sites.

With the path cleared for Paranal and the ELT, the future of astronomy looks brighter. As Johan Fynbo says: 

“The desert is so vast that it should be possible to find another place for such an energy project.” He does not rule out a possible balance, but one that requires dialogue, regulation, and above all, prioritizing an irreplaceable resource: the darkest skies on the planet.