Bad timing for Montreal-area fireball: expert
Snowfall has hidden the location of any meteorites, writes TOM SPEARS.
After Tuesday evening’s flash and bang over Montreal, we asked meteor experts Richard Herd and Peter Brown how to find rocks from the sky, and what they are like. Herd is the retired curator of Canada’s national meteorite collection, and Brown is a Western University professor.
How do you find a meteorite?
In this case, “all you can do is hope that it hit something that shows some damage, like a building or a shed,” said Herd. If it landed in the open, he says, there’s practically no hope until spring.
So this was terrible timing?
Yes, in the sense that snow immediately covered the area. “Unless it hit something, it won’t be found immediately,” said Herd.
No, in the sense that it happened at 8 p.m. That means it hit the side of Earth that was facing “backwards,” away from Earth’s direction of travel around the sun. This would soften the impact a little and potentially allow more rock to survive the fiery trip through the atmosphere.
How big was it?
Impossible to tell, but it’s rare for more than a few kilograms of rock to be found.
The rock that fell near St-Robert, Que., in 1994 was estimated at one tonne and a metre wide when it entered the atmosphere, but only about 20 kg of rock was found.
What’s a meteor? What’s a meteorite?
The falling rock that causes a fireball, or a shooting star, is a meteor. Any pieces found afterward are meteorites.
Can we track them?
With luck they show up on security cameras, home video, a NASA satellite, or a network of cameras (there’s one in southern Ontario) that are set up to watch for meteors.
Peter Brown runs the network of sky-scanning cameras. The closest
The St-Robert meteorite of 1994 landed in a cow pasture. The cows got agitated and the farmer came to see what was bothering them. He found the rock.
one to the event is in Kingston, but at 8 p.m. it was totally obscured by heavy cloud.
He thinks the meteor flew north of Montreal before that area clouded over.
“You’re probably talking about a wooded area, and with the snow it’s even worse.”
Microphones in southern Ontario that record sonic booms didn’t catch anything.
“We are in the process of installing a camera in Ottawa,” Brown said. “Maybe I’ll put one in Montreal so the next time this happens we can answer everyone’s questions immediately.”
The Ottawa camera will likely be mounted on a colleague’s house in a few months.
How have past meteorites been found?
The Peekskill meteorite (named for the town in New York where it landed in 1991) hit a parked car and sank into the road under it. The car was an old Chevy Malibu that a teenaged girl had just bought for $300, but she sold it for $10,000.
The St-Robert meteorite of 1994 landed in a cow pasture. The cows got agitated and the farmer came to see what was bothering them. He found the rock and although it had cooled it made his hand tingle — possibly from static electricity.
Herd says Canada paid $10,000 for the St-Robert rock, which started a frantic search for funny-looking rocks on all the neighbouring farms. “And when people found out that we paid $10,000 for a rock that came from a cows’ pasture, boy did they have a deal for us!”
Some meteorites are found by people scanning with metal detectors.
What are they made of?
All kinds of minerals and metals, ranging from nickel-iron (very dense and solid) to flimsy clusters of rubble that tend to disintegrate in the atmosphere.
Herd says they take only a matter of seconds to go from space through the Earth’s atmosphere. Coming in at tens of thousands of kilometres an hour they partially melt, deform and break up as they fall.
The fireball effect isn’t really fire. It’s the heat and pressure stripping electrons off atoms of gas in the atmosphere. Returning spacecraft do the same thing.
Final thoughts?
Herd: “It’s ironic — the first snowfall of the season and there’s a meteor, maybe.”