The European Southern Observatory is at serious risk of losing clear skies over its Paranal Observatory in Chile’s Atacama Desert, officials said, because of a proposed industrial complex set up ahead of the subsidiary. of a US power company.

The Paranal Observatory is home to ESO’s Very Large Telescope (VLT), which consists of four telescopes each with a 27-foot (8.2-meter) mirror and four auxiliary telescopes with a 6-foot (1.8 -meter) mirror. Working together, the telescopes produce some of the sharpest views of the universe. Officials of the observatory are seriously concerned that the proposed industrial project will continue, which will reduce the visibility of Paranal and permanently change the night vision of some of the best skies for astronomical research.

Right next door

The project, called Inna, is a proposed industrial-scale green hydrogen project. The total footprint of the project will cover more than 7,413 hectares in the Atacama and will include a port, ammonia and hydrogen production plants, and thousands of electric generators.

All of this would have to be built from scratch, with the proposed project site located 3 to 7 miles (5 to 11 kilometers) from the Paranal telescopes. The company, AES Andes, submitted an Environmental Impact Assessment for the project to Chilean authorities last month.

“As with any project, our partnership with local communities and stakeholders is a top priority, ensuring that we support local economic development, while maintaining the highest environmental and safety standards, ” said Javier Dib, AES’ Chile Market Business Leader, in a company statement announcing the submission.

Well, environmental impacts are exactly what officials at the European Southern Observatory are concerned about. The Atacama Desert has some of those darkest, clearest sky anywhere on Earth. There is less moisture in the air, which reduces the amount of light absorbed by water in the atmosphere, and it is at a higher elevation, which reduces the amount of shaking that Earth-based astronomers usually have to deal with when imaging distant sources through the atmosphere.

Paranal’s unique location and impact

From its perch in Chile’s Atacama, the Very Large Telescope captures ancient and recent astronomical events alike, in our galaxy and beyond its reach. In 2021, the telescope taken pictures of the 42 largest asteroids in the solar system. It continues the trend of space rock in 2023, when the two teams reveals telescope images after NASA’s DART mission, which tested the viability of changing the orbit of a natural body in space. In the same year, the telescope visible gas clouds that may have formed after the first stars and, just two months ago, another team used the telescope to capture the first detailed image in a star outside our galaxy.

Due to Atacama’s natural disposition for astronomy, it is home to many existing and planned telescopes, including Paranal, the Rubin Observatory (which hosts the largest digital camera in the world), and the under -construction. Giant Magellan Telescope at Las Campanas Observatory. The LSST Camera at the Rubin Observatory is scheduled to have first light later this year—something that has been anticipated for a year. filled with astronomical events.

“Chile, and especially Paranal, is a truly special place for astronomy – its dark sky is a natural heritage that will transcend its borders and benefit all humanity,” said Itziar de Gregorio , ESO Representative in Chile, at an observatory. release. “It is important to consider alternative locations for this megaproject without damaging one of the world’s most important astronomical treasures.”

In 2022, a group of researchers found that the light pollution of Paranal is lower than 27 other major observatories. The research found that two-thirds of all major observatories studied by the team now have an increase in light pollution of 10% over the assumed natural level, suggesting that light pollution is already harming astronomical observations.

“The results arising from this work are sending what may be the last call for a serious, collective, unequivocal, uncompromising action to reduce light pollution today, even if it generated from artificial light or from sunlight reflected by artificial objects in orbit,” the team wrote. “Failure to move means a progressive decline in our ability to explore our Universe.”

Astronomy under threat

“The proximity of the AES Andes industrial megaproject to Paranal poses a critical risk to the cleanest night sky on the planet,” said ESO’s Director General, Xavier Barcons, in the observatory’s release. “Dust emissions during construction, the increase in atmospheric turbulence, and especially light pollution have irreversible effects on the capabilities for astronomical observation, which until now have attracted multi-billion- Euro investment by the governments of the ESO Member States.”

Earth’s infrastructure is not the only concern of astronomers. The earth’s orbit is filled with satellites which complicates the description of the night sky. Megaconstellations including SpaceX’s Starlink create streaks on astronomical images as individual spacecraft move through the night sky. That satellite swarms even bothersome space-based telescopes, some of which can be seen by the Hubble Space Telescope. pictures. there cleaning tricks astronomical images of these streaks, but they are still a problem.

Light pollution is getting worseaccording to new research. In 2023, a team of researchers reviewed more than 50,000 observations made worldwide between 2011 and 2022 as part of NOIRLab’s Night Globe project. The researchers found that the night sky became 9.6% brighter every year, causing some dim stars to disappear completely from the sky for some stargazers.

The effect of light pollution in the Atacama and astronomy

Eventually, the Very Large Telescope will replace the Very Large Telescope (inventive names, I know), which will be 128 feet (39 meters) across and is set to be the largest visible and infrared light telescope in the world. The Largest Telescope will collect 100 million times more light than the human eye and will reveal details of distant exoplanets, black holes, the evolution of galaxies, and the early days of the universe. The telescope will be located near the VLT, at Cerro Armazones, and its first light is expected in 2028—although ESO’s website offers a more cautious “end of this decade.”

“Astronomical observatories can be seen as the proverbial canary in a coal mine,” wrote the team that examined the relative obscurity of the observatories’ skies in its 2022 paper. “If we cannot keep the canary alive, then we will forget to solve the problem of light pollution as a global environmental issue.” In addition, the group noted, among others negative consequences Light pollution will continue, including the disruption of circadian rhythms and other negative consequences for the health of Earth’s biodiversity.

In its release, ESO advocated for the transfer of the AES Andes project, saying that the transfer of the industrial complex “remains the only effective way to prevent irreversible damage to the unique skies of Paranal.” Meanwhile, the company is awaiting word from the Chilean authorities on whether the project’s environmental impact is too small to proceed as proposed.

The basis of the company’s message is to decarbonize its energy matrix and increase the amount of energy obtained from renewable sources. There is a painful irony in the Chilean authorities allowing a green energy project to continue at the expense of clear skies for astronomers.