Q&A WITH AN ASTROPHYSICIST

Light pollution is a growing threat worldwide. Now astronomers are battling an industrial project in Chile that could compromise some of Earth's darkest skies

- Anita Chandran

What makes Chile, specifically the Atacama Desert, a prime location for looking at the cosmos?

Chile is the best place on Earth for doing astronomy in different wavelengths. We have very clear and quiet skies, which are perfect for observations in the optical and infrared. We also have high, dry places in the mountains which are good for ‘millimeter’ and ‘submillimeter’ astronomy. Observing sites like the European Southern Observatory (ESO) Paranal site are in the middle of the Atacama Desert, far from big cities and their associated light pollution.

What exactly is light pollution?

It's the brightening of the sky caused by the excess light that we human beings emit into the atmosphere. We emit a large amount of unnecessary light - say, from poorly positioned streetlamps and the blue light component of LEDs - which can brighten the sky far away from the pollution’s source.

How does it affect astronomy?