A meteor streaks past the Milky Way during the annual Perseid Meteor shower on Aug 12 2015. The Perseids occur every year around mid July peaking in mid August, when the earth passes through the debris field of Comet Swift-Tuttle.Fred Lum/The Globe and Mail
The bright flashes slicing through the summer sky are an annual spectacle, but this year's Perseid meteor shower has the potential to be especially captivating, with some astronomers predicting 200 meteors every hour– one of the best in 20 years.
The week-long Perseid shower happens every August, when Earth grazes a debris trail left when the Swift-Tuttle comet passed by in 1992 on its 133-year orbit. Fresh debris typically result in the best meteor showers, but this summer could produce unusually exciting results, with early Friday morning expected to be the best viewing time.
That is because the gravitational wobbles of Jupiter have pushed more of the debris close to Earth, said Randy Attwood, executive director of the Royal Astronomical Society of Canada. These dust particles reach speeds of 60 kilometres a second as they enter the atmosphere, burning up and creating brilliant streaks of light.
One meteor every couple of minutes is typical for a meteor shower, with the Perseids usually producing one every minute, Mr. Attwood said. But the International Meteor Organization, a group of amateur astronomers around the world, predicts double the meteors of an average Perseid shower this year.
Mr. Attwood cautions that nothing is guaranteed.
"They're tricky things to predict – you're talking about a field of debris that could be spreading," he said.
In the past, astronomical events have been breathlessly hyped, only to fizzle out. The 1973 Comet Kohoutek, dubbed at the time the "comet of the century," failed to live up to lofty expectations.
"[Kohoutek] was going to be this amazingly bright Christmas comet. It was a dud. You could hardly see it with the naked eye," he said.
"If the expectation is that you're going to go out into your backyard and see a few hundred meteors, like a Star Wars movie, you're going to be extremely disappointed."
A number of factors could derail ideal viewing conditions, but the biggest threats are light pollution and weather.
For those hoping to catch a glimpse, astronomers suggest leaving the city. Much of the appeal of the Perseid shower is that it is most visible when many people are away from cities on summer vacations.
Gazing up at the sky and looking at nothing in general is the best approach, astronomers say. This makes it easier to spot meteors that are visible for only a couple of seconds.
To appreciate fully the majesty of flaming comet dust, the shower is best viewed with the backdrop of a predawn sky. Friday between 2 a.m. and 4 a.m is ideal, Mr. Attwood said.
Meteors are harder to see during the day and early evening. By the wee hours of Friday, the Earth will have moved into a position that provides the best view of the debris crashing into the atmosphere.
Finding a dark area might not be enough – most of the country is forecast to have cloud cover during the ideal viewing times, with the exception of the West Coast.
Even if this summer's shower does not play out as expected, Mr. Attwood said, there is a beauty to the small bits of dirt and debris entering the atmosphere almost daily, not just in August.
"You're seeing a little piece of the solar system that's been floating around for 4.5 billion years, most likely … and it just happens to collide with the earth," he said. "And you are the one who actually sees it actually get burned up."