Sky watchers across Canada could be treated to a particularly lively version of the annual Perseid meteor shower, thanks to an absence of moonlight and a favourable weather forecast for much of the country.
Meteors are small particles of space dust that burn up when they plunge through Earth's atmosphere at high speeds. To the eye, they appear as fleeting streaks of light that dart across the sky.
During the Perseid shower, Earth passes through an entire stream of such particles all moving in the same direction. Under ideal conditions, dozens of meteors per hour can be seen lighting up the sky around the shower's peak, which this year falls on Wednesday night and early Thursday morning.
Because the Perseids always appear right after the feast of St. Lawrence on Aug. 10, they have been nicknamed St. Lawrence's tears. But the shower's official name stems from the fact that the meteors appear to emanate from the constellation Perseus, which happens to lie in the direction of the approaching stream.
The shower will likely be most active before dawn on Thursday, local time, when Perseus sits high above the northeastern horizon for observers across much of Canada, but it's worth looking as soon as evening twilight fades on Wednesday night.
"Arguably the most spectacular meteors can be seen shortly after it is dark," said Peter Brown, an astronomer at Western University in London, Ont., and a world expert in the study of meteors.
"At this time, the Perseids enter the atmosphere on shallow paths and they will make very long streaks across the sky, sometimes lasting a few seconds."
Dr. Brown said that he and his team will be deploying a new suite of cameras to record the Perseids this year. Their objective is to analyze the light from the incoming meteors to better determine particle mass and chemical composition.
"Meteor showers are convenient targets for these sort of studies as there are far more bright meteors during the showers than at random times," he said.
Although some Perseids can briefly shine as brightly as the brightest stars, most are much fainter so the shower is best observed under dark skies far from city lights.
Last year, a nearly full moon washed out all but the brightest Perseids during the shower's peak. This year, the shower coincides with a new moon, which should result in a far better show.
Weather forecasts favoured observers across Western Canada from the Pacific to the Great Lakes. Skies are more likely to be cloudy for those watching further to the east.
How to watch for Perseids
1) Find a dark, open area away from street lights and preferably well outside of the city.
2) Dress warmly, and have something warm to drink; it's a lot cooler at night than you think, especially in the wee hours.
3) Bring something comfortable to sit on, like a deck chair that lets you lean back and take in the whole sky.
4) Scan the skies and be patient. During a good shower, a meteor will show up about every minute or so. Perseids will typically seem to be travelling from the northeast but may appear anywhere in the sky.