The Atacama Desert’s night sky, long prized by astronomers for its unmatched clarity, faces growing pressure from nearby energy development despite recent project cancellations.
Scientists successfully blocked a green power complex near Paranal Observatory
In January, an energy firm’s proposal to build a green power complex just kilometers from the European Southern Observatory’s Paranal site was canceled after a broad appeal from astronomers, physicists, and Nobel laureates. The project had raised alarms due to its potential to introduce light pollution into one of the world’s most sensitive astronomical zones. Paranal, located in Chile’s Photon Valley, hosts some of the most advanced telescopes on Earth and is slated to house the Extremely Large Telescope, the most powerful optical observatory ever planned. The cancellation came after scientists emphasized that even distant artificial light can degrade observations by scattering in the atmosphere and reducing contrast needed to detect faint celestial objects.
Existing light protection laws in Chile are under review for being too weak
Although the immediate threat was averted, the episode exposed gaps in Chile’s regulatory framework for preserving dark skies. Officials from the science ministry and the Cielos de Chile Foundation confirmed that current laws governing astronomical protection zones are outdated, lack clear enforcement mechanisms, and do not sufficiently buffer observatories from indirect light sources. Daniela González, director of the Cielos de Chile Foundation, said authorities are revising criteria to ensure any future development near protected zones will have zero impact on observational conditions. The review includes reevaluating buffer zones, emission limits for artificial lighting, and monitoring protocols for projects within dozens of kilometers of major facilities.
For more on this story, see US DESI Project Completes Largest 3D Map of the Universe.
Chile’s northern desert remains a global hub for astronomy despite vulnerabilities
Despite these risks, the Atacama continues to draw thousands of scientists annually due to its exceptional observing conditions: over 300 clear nights per year, extreme dryness, high altitude, and minimal atmospheric turbulence. The region hosts nearly 30 astronomical sites, most operated by international collaborations, including the European Southern Observatory, ALMA, and Las Campanas Observatory. Access remains competitive, with only 20% to 30% of applicants selected for visiting time at Paranal. Experts like Julia Bodensteiner of the University of Amsterdam note that losing even a fraction of this darkness would significantly hinder research into cosmic origins, galaxy formation, and dark energy — work that relies on detecting the faintest signals in the universe.
This follows our earlier report, Justice Lab Explores Renewable Energy Transition in California and Nevada.
Why is the Atacama Desert ideal for astronomy?
The Atacama combines extreme dryness, high elevation, and geographic isolation, resulting in over 300 cloudless nights annually and minimal light pollution — conditions unmatched elsewhere for ground-based optical and radio observations.
What kind of threat does distant lighting pose to telescopes?
Even low levels of artificial light can scatter in the atmosphere, creating a bright haze that reduces the contrast needed to observe faint galaxies, distant supernovae, and other dim astronomical objects critical to understanding the universe.
