in Greener Homes on 5 June 2011
Too much light is damaging to our nights
ON Thursday, Friday and Saturday evenings, when the sky is clear, Jack Mack lugs his telescope, computer, card tables and folders to the front of his Abbotsford home. He positions a sandwich board, which reads: “Welcome to Footpath Astronomy”.
He’s been doing this for four years, on Nicholson Road, next to the Retreat Hotel. “It gives people an opportunity to see the moon, a planet or a star cluster through a telescope,” he says.
Most city-dwellers notice the moon and nothing more. “People walk past and I say: ‘Sit down here and look in the eye piece’. And they’re absolutely blown away. Saturn is the crowd favourite, because you can easily see the gap between the planet and its rings.”
In 1610, when Galileo observed for the first time that the Milky Way was made up of individual stars, our galaxy was so bright it cast shadows on the ground. Now, from where we live, most Australians can’t see the Milky Way at all.
Mr Mack is a member of the Astronomical Society of Victoria, which has a dark sky viewing location near Heathcote in central Victoria. Even from there, the glow from the city encroaches upon the sky.
“It’s light pollution,” he says. “At least in the bush you can see the Milky Way with the naked eye. As you get closer to the city, the light gets denser and you see fewer and fewer objects.”
That’s not the only adverse effect of light pollution. Mark McDonnell, director of the Australian Research Centre for Urban Ecology, says it’s a threat to biodiversity and alters animal behaviour and feeding habits.
“Night-flying insects cannot resist the light. Research from Europe has shown a dramatic reduction in the number and diversity of insects, particularly moths, in cities when compared to the village-farmland edge. They estimate billions of insects are dying,” he says.
“It not only reduces food sources for animals, but also it reduces the number of pollinators. Light pollution also affects when plants flower and when they go dormant for the winter.”
The International Dark-Sky Association website carries useful guides on light pollution and residential lighting. Mr McDonnell believes householders can take a lead in reducing its harmful effects.
“We shouldn’t have lights that shine up. Some homes are lit up like landing fields around doors, paths and garages. We can shield lights so they’re only directed downwards. We can use motion detectors and timers to switch lights off when no one’s around.”
All our lighting also sucks energy. Last year, the Municipal Association of Victoria launched the Give our streets the green light campaign, aiming to secure state and federal funding towards the up-front cost of more efficient street lights.
It estimates that better globes and fittings would cut lighting energy use by over two-thirds and cause three to four times less light spillage.
Mr Mack, flanked by two freeways, the city and the MCG, says light pollution is bad and getting worse. Even so, he can still summon wonder among passers-by. On a good night for seeing, he shows the moon. “I do it from a low magnification first, then I put in a higher power and they’re looking inside a sea pockmarked with craters,” he says. “The moon is just as fascinating as anything in the solar system.”