Light pollution: a starry sky on the verge of disappearing – Le Journal de Montréal

Light pollution: a starry sky on the verge of disappearing – Le Journal de Montréal

The dark skies are disappearing much faster than expected, reveals a new study based on more than 50,000 sightings from citizens around the world. And Quebec is no exception.

“The increase in light pollution is staggering. It’s two to three times more than we thought,” says physics professor at Cégep de Sherbrooke Martin Aubé, aware of the results published a few days ago in the prestigious journal Science.

The study in question shows that the night in North America has brightened by an average of 10.4% each year since 2011, according to the participants’ 51,351 naked-eye observations.

“Honestly, I don’t think Quebec is an exception, except in certain regions where efforts are being made,” says Rémi Boucher, scientific coordinator of the Mont-Mégantic International Dark Sky Reserve.

Harmful street lights

In Quebec, as elsewhere, this increasing pollution is partly explained by the installation of streetlights equipped with LEDs (light emitting diodes) in cities and on the streets.

“They contain a higher proportion of blue light [que l’ancien éclairage jaune au sodium]which makes them much more harmful,” explains Martin Aubé.

Their impact on light pollution has also been grossly underestimated in the past, as the satellites most commonly used to explore the Earth at night are “blind” to the blue light they emit.

“We were able to show that citizen science is an important addition to previous measurement methods,” said Christopher Kyba, main author of the study at the GFZ Potsdam Center for Geoscientific Research, in a press release.

Farewell, little car

Today, many residents of large Québec cities cannot even admire the constellation Lesser Bear on a moonless night.

“Only the brightest planets and stars remain,” says Rémi Boucher, who has long led introductory astronomy workshops.

greenhouses too shiny

The high level lighting of agricultural greenhouses, which is being promoted by the government with the goal of developing Quebec’s food autonomy, also exacerbates light pollution.

For example, the orange glow of the Toundra greenhouses in Saint-Félicien (in Saguenay-Lac-Saint-Jean) can be seen from at least 80 kilometers away.

“It hurts us when we want to observe the northern lights in the north,” laments Claude Boivin, president of the local astronomy club Boréalides.

After all, human and animal health is also affected by light pollution, particularly that of many nocturnal animals, emphasizes Professor Martin Aubé.

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