Astronomers Urge Chilean Government to Protect Atacama Night Sky from Industrial Project

Threat to World's Darkest Skies

An international consortium of astronomers is urging the Chilean government to intervene and protect the exceptionally dark skies above the Paranal Observatory in the Atacama Desert. The observatory, home to the European Southern Observatory's (ESO) Very Large Telescope (VLT) and the under-construction Extremely Large Telescope (ELT), is considered one of the world's premier sites for astronomical research due to its unique atmospheric conditions and minimal light pollution.

The concern stems from a planned industrial megaproject, named INNA (Infraestructura Energética para la Generación de Hidrógeno y Amoníaco Verde), proposed by AES Andes, a subsidiary of the US electricity company AES Corporation. The project, which includes a port, facilities for green ammonia and hydrogen production, and thousands of power generators, is slated to cover more than 3,000 hectares (7,400 acres). Its proposed location is alarmingly close to the observatory, ranging from 5 to 11 kilometers (3 to 7 miles), with some components as near as 3 kilometers (1.9 miles) to the telescopes.

Potential Impacts on Astronomical Research

Experts warn that the INNA project poses multiple threats to the observatory's operations. An in-depth analysis by ESO indicates that light pollution above the Very Large Telescope could increase by at least 35%, and by more than 50% over the Cherenkov Telescope Array Observatory (CTAO-South). This increase could downgrade Paranal's sky quality from 'excellent dark sky' to 'rural sky'.

Beyond light pollution, the project's construction and operation are expected to generate significant amounts of dust, which would aggravate light scattering and further degrade sky quality. Furthermore, the industrial complex could cause disruptive micro-vibrations, potentially impairing the highly sensitive operations of telescopes like the ELT. The presence of wind turbines, part of the renewable energy complex, could also stir the atmosphere, leading to increased atmospheric turbulence that might worsen observing conditions by up to 40% and cause stars to 'twinkle'.

Global Scientific Community Unites

The scientific community has voiced strong opposition to the project's current location. An open letter, signed by nearly 30 eminent international astronomers, including 2020 Nobel laureate Reinhard Genzel, has been sent to the Chilean government, urging the relocation of the INNA complex. The letter emphasizes that the potential damage would extend globally, affecting the worldwide scientific community that relies on observations from Paranal to study phenomena ranging from planet formation to the early universe.

Daniela González, executive director of the Skies of Chile Foundation, has also highlighted the importance of protecting Chile's night skies, which are considered a 'perfect cocktail for astronomy' due to the Atacama Desert's dry climate, high altitude, and isolation. María Teresa Ruiz, the first woman in Chile to receive the National Prize for Exact Sciences, was among the first to raise concerns about the threat.

Chile's Commitment to Dark Skies

Chile currently hosts a significant portion of the world's astronomical infrastructure, with estimates ranging from 40% to 70%. The country has recognized the importance of its dark skies through various protective measures, including a National Lighting Standard set to become effective later this year (as of April 2024) and a decree from June 2023 that established 'astronomical areas' to safeguard observation sites.

While AES Corporation maintains that its own technical studies indicate the project would be compatible with astronomical observations and compliant with Chilean regulations, the project remains under environmental review. Astronomers, however, stress that economic development and scientific progress must coexist without sacrificing one of Earth's irreplaceable windows to the universe.