How Light Pollution Is Threatening the Very Large Telescopes in Chile: An Expert’s Warning

In the latest development, astronomers have expressed concerns about a renewable energy project in Chile that threatens the world’s most famous observatory.

The site is located in the Paranal Mountains, home to the European Southern Observatory’s (ESO) Very Large Telescope (VLT), one of the most advanced sky-observing instruments.

The planned INNA hydrogen production project, supported by the US-based AES Energy, may cause light pollution, thereby impairing the VLT’s observation capabilities.

Source: ESO/Space.com

Where is the location?

Mount Paranal, located in Chile’s Atacama Desert at an altitude of 8,740 feet (2,664 meters), is considered one of the darkest places on Earth and provides near-perfect conditions for astronomical research.

What is VLT? Why is it important?

  • The Very Large Telescope was worth $350 million (equivalent to $840 million today) and was one of the most sensitive instruments for observing the universe.
  • It consists of four 8.2-meter-wide telescopes that work together to provide insights into cosmic phenomena, including black holes, exoplanets, and the cosmic web.

Source: ESO/Space.com

What are the threats?

  • AES Energy proposed the INNA hydrogen project, which includes solar and wind farms, battery storage systems and hydrogen production facilities.
  • The development, covering more than 3,000 hectares, is expected to increase sky brightness by 10%. This could seriously affect the quality of observations and make it difficult to study faint galaxies and exoplanet atmospheres.

What are the effects of light pollution?

  • Astronomical consequences:

    • “A 10% increase in light pollution could reduce the quality of observations at Mount Paranal,” ESO Director General Xavier Barcons said in a statement to Space.com.
    • This could lead to a loss of detail in observations of the faintest galaxies and exoplanets, compromising scientific progress made through future projects such as the VLT and the Extremely Large Telescope (ELT).
  • ELT and future prospects:

    • The ELT is being built near Mount Amazones and will be the world’s largest visible light telescope.
    • It will feature a 39.3-meter-wide mirror expected to expand our understanding of the universe.
    • However, the light pollution anticipated by the INNA project may impair its research capabilities.

What are the environmental and economic considerations for the INNA project?

  • Energy transition and astronomy: The $10 billion INNA project promises to produce 217,023 tons of green hydrogen per year. While it aligns with global efforts to transition to renewable energy, its proximity to the observatory poses a direct threat to scientific progress. ESO highlighted the potential for relocating such projects to areas less sensitive to light pollution.

Note: What is the INNA project under Green Hydrogen (H2)?

  • The INNA project, developed by AES Andes in partnership with Samsung C&T, is a large-scale green hydrogen and ammonia initiative in Chile.
  • The project uses renewable energy sources such as solar, wind and battery storage to support Chile’s national green hydrogen strategy while promoting local economic growth and adhering to strict environmental standards.
  • AES Andes has submitted an Environmental Impact Assessment (EIA) and is actively exploring opportunities for green hydrogen production and export.

Source: Shutterstock

  • Chile’s role in astronomy: Due to its clear skies and remote location, Chile is home to some of the most important observatories in the world. The country has passed regulations to curb light pollution near observatories in 2023, but further steps are still needed to protect these key research sites.

In summary, the development of renewable energy projects is critical to combating climate change, and the unique requirements of scientific research in fields such as astronomy cannot be ignored.

The European Southern Astronomical Organization has called for stronger legal protections to protect the night sky in areas such as the Atacama Desert, stressing the need to balance environmental, scientific and economic interests.