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| Sat, 10th Dec 2022 14:08:00 |
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Blinded by the light: how skyglow pollution is separating us from the stars |
Light infrastructure has expanded alongside population growth but it’s not only star gazing in jeopardy – cultures, wildlife, science and human health are all threatened
On a clear dark Queensland night in 1997, Brendan Downs was staring up into the cosmos alongside a band of other amateur astronomers. He trained his telescope on a galaxy called NGC 6769, floating more than 169m light years away, and took a picture.
“I had a reference image that I had in a book at the time, and I visually compared the object on the screen to the object in the book,” he says. “I counted the number of stars I was looking at.”
One, two, three, four, five …
One, two, three, four, five, six …
“I should be able to count easily,” he says. “My heart rate goes up. I went to a couple of friends and, very quickly, everyone could see there was an extra star in the image I took.”
He had captured the explosion of a star, a supernova. The discovery – shared with a New Zealand astronomer who photographed the same blast of light that night – was registered with the International Astronomical Union under the name 1997de.
Downs went on to discover a second supernova, 2010dc, in his back yard Thunderchild Observatory in Ipswich, west of Brisbane, and has helped to confirm countless others.
In back yard observatories around the world, amateur astronomers’ discoveries are contributing valuable data to scientists. When researching the origins of the universe, Brian Schmidt’s team of scientists, who later went on to win a Nobel prize, often called on a group of astronomers Downs was involved with to capture objects of interest.
Yet one threat to astronomy is slowly curtaining the view beyond our atmosphere. It’s all over the world, it’s in your street and it glows from every bulb: light pollution.
It’s not only star gazing that’s in jeopardy. Culture, wildlife and other scientific advancements are being threatened by mass light infrastructure that is costing cities billions of dollars a year as it expands alongside exponential population growth.
Some researchers call light pollution cultural genocide. Generations of complex knowledge systems, built by Indigenous Australians and Torres Strait Islanders upon a once-clear view of the Milky Way, are being lost.
In the natural world, the mountain pygmy possum, a marsupial native to Australia, is critically endangered. Its main food source, the bogong moth, is being affected by artificial outdoor lighting messing with its migration patterns. Sea turtles are exhibiting erratic nesting and migration behaviours due to lights blasting from new coastal developments.
So how bright does our future look under a blanket of light?
“If you go to Mount Coot-tha, basically the highest point in Brisbane, every streetlight you can see from up there is a waste of energy,” Downs says. “Why is light going up and being wasted into the atmosphere? There’s no need for it.”
Skyglow
Around the world, one in three people can’t see the Milky Way at night because their skies are excessively illuminated. Four in five people live in towns and cities that emit enough light to limit their view of the stars. In Europe, that figure soars to 99%.
Blame skyglow – the unnecessary illumination of the sky above, and surrounding, an urban area. It’s easy to see it if you travel an hour from a city, turn around, then look back towards its centre.
Read original full article
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