Lighting up the sky: Canada’s history of meteorites
TORONTO – On Sunday, residents across the Greater Toronto Area and east as far as Belleville were treated to a rare event: a daytime meteor.
These events happen a few times a week, astronomers believe. But, as Earth is mostly covered in oceans, deserts (and that includes Antarctica) or uninhabited areas near the poles, most of them go unseen.
First, to be clear, a meteor is a piece of space dust or debris that burns up in our atmosphere. It only becomes a meteorite once it hits the ground. A meteoroid is space debris. And if you’ve heard the word “bolide” to describe a meteor, it just means that it was an extremely bright meteor. It can also be called a fireball.
For the most part, our atmosphere protects us from being bonked on the head by falling space rocks. But if it’s large enough, the rock — or pieces of it — will make it to the ground.
Most recently, a large meteor was seen falling in Chelyabinsk, Russia in February 2013. The resulting airburst from the huge piece of rock damaged homes and injured 1,000 people. And this isn’t the first time Russia had a brush with a massive meteor. In 1908, an asteroid that was about 37 metres in diameter flatted 2,000 square kilometres of forest and was felt 64 km away.
But Canada has had its fair share of meteor events, too.
Buzzard Coulee, 2008
On Nov. 20, 2008, a bright fireball was seen soaring across the sky in Alberta, Saskatchewan, and Manitoba around sunset. Shadows were cast by the fireball and explosions were reported. Some people even reported hearing “whirring” sounds, believed to be caused by debris falling to the ground.
Scientific instruments recorded the release of energy, estimated to be around a third of a kiloton, suggesting the meteoroid was about 10 tons before it entered the atmosphere.
Fortunately, it was cold and some of the debris fell on a lake. In the end, more than 100 pieces were recovered before snow covered the search area.
Tagish Lake, 2000
On Jan. 18, 2000, around 8:40 p.m. local time, a brilliant fireball lit up the sky over Yukon and northern British Columbia. The fireball was extremely bright, and was soon followed by loud booms that echoed across the countryside.
Jim Brook, one of thousands to have witnessed the event, knew the importance of what he saw. While driving home, he picked up the pieces of the meteorite with a plastic bag around his hand, thus helping to keep the ancient rocks free of any earthly contamination. It was also fortunate that the meteorite fell over a frozen lake: it helped to further preserve the specimens. Scientific instruments recorded the meteor’s initial entry into our atmosphere, and at the time, it was the largest recorded event over land.
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Astronomers from the University of Calgary and Western University went to the site in February 2000, conducting further research.
They estimated that the meteorite was 150 tons, entering the atmosphere at 16 kilometres per second with a force of about 1.7 kilotons.
More than 500 pieces of the 4.5 billion year-old meteorite were found, though only about 200 were recovered.
On the night of February 5, 1977, several people witnessed a bright fireball in the early evening in Innisfree, Alberta.
A search party went out to search for it — both on foot and by plane — but found nothing. Eleven days later, about 13 km north of Innisfree, the 2.07 kg piece of rock was found. Another five fragments were found in April, bringing the total recovered pieces to be almost 4 kg.
It is estimated that the total mass of the meteor was 4.58 kg.
Though these meteorite impacts created a buzz and were able to provide scientists with a better understanding as to the formation of our solar system, there are plenty of meteorite impacts that we were — fortunately — never around to witness.
One of those has left a long-lasting scar on Canada: in Manicouagan, Que.
The rock that was responsible for that is estimated to have been 85 kilometres in diameter. If you figure that the Chelyabinsk meteorite — that injured about 1,000 people — was a mere 19 metres in diameter, it’s fair to say that it’s a lucky thing we weren’t around to feel that one. The meteor or asteroid responsible for that paid us a visit more than 200 million years ago.
Though most meteors are seen at night, the meteor over Toronto reminds you to keep an eye on the sky. You never know what can happen.
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