How light pollution undermines search for other planets

We know all about the pollution of our water, air, and soil, but how much have you thought about light pollution?

    Atacama Desert, Chile – At the Paranal Observatory, Italian astronomer Eleonora Sani is working through the night studying black holes on one of four eight-metre telescopes.

    Nearby, her French colleague Pascale Hibon is determined to discover where the universe ends, while Chilean astronomer Fernando Selman’s work is earmarked to answer perhaps the most important question of all: Is there life on another planet?

    Paranal is one of three European Southern Observatory (ESO) observatories in Chile’s Atacama Desert, where by 2020 it is estimated that 70 percent of the world’s astronomical infrastructure will be located.

    That includes what will be the world’s largest telescope, the $1.3bn European Extremely Large Telescope.

    The United States, Canada, the UK, Australia, Brazil, Argentina and Chile are also investing heavily in next generation technology.

    All of that investment could help determine if we are indeed alone in the universe.

    With cloudless skies for at least 300 days each year, and enviable atmospheric characteristics for star gazing, the Atacama Desert is an astronomer’s paradise.

    But in recent years, ever expanding contamination from light pollution – especially from cheap, white LED lighting – is raising alarm bells among astronomers trying to safeguard some of the world’s darkest skies.

    “They are illuminating more because they have a very large bump in the spectrum of the light in the blue area, which causes the most interference. There are laws in areas near observatories, but they need to be enforced much more,” says Selman.

    Light pollution from cities like Antofagasta, La Serena and Coquimbo, as well as giant copper mines in the Atacama, have deteriorated darkness by 30 percent in the last decade, according to the Office for the Protection of Quality of the Sky (OPCC).

    Fernando Cameron, a former OPCC director, describes dark skies not just as a Chilean but a global natural resource that is becoming increasingly scarce.

    “All you have to do is look at the images of Earth taken from space to see just how illuminated our planet is at night. It not only impacts astronomy – making it more difficult for our instruments to obtain precise measurements – but also life on our Earth as we know it,” says Cameron.

    Even in the Atacama Desert, cities are expanding and contaminating darkness with excessive lighting in homes and billboards.

    Chile’s government is keen to preserve the country’s prestige as an international observatory centre. To its credit, it has imposed tougher lighting standards in the three provinces of the Atacama where observatories exist.

    But much more needs to be done.

    Astronomers say the sky quality in the Atacama is still incomparable. But, as elsewhere in the world, authorities are being urged to increase measures to diminish light pollution.

    “We need to respect night-time darkness and save the skies, not just for astronomers but for all human beings who have a right to gaze at the stars,” says Cameron.

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