Ottawa Citizen

More about meteorites

Many turn out to be ‘meteorwron­gs’


Tens of thousands of confirmed meteorites, and far more unconfirme­d ones, have fallen to Earth. Over time, humans have held these events in varying degrees of religious awe, hostile suspicion, superstiti­ous fervour and scientific curiosity. Regarding the latter, meteorites are important to scientists because they are a rare source of extremely old material.

“The comets are composed of material that comes from the beginning of our solar system,” says Richard Herd, former curator of the National Meteorite Collection of Canada, “and some material that is older than our solar system.

“They are pieces of stuff that are at least as old as the sun,” he adds, “and when you think about it, that’s all recycled material, from older material. The only thing that’s being made in our solar system in any quantity is helium, by the fusion of hydrogen in the sun. But everything else is made from material that is four or 4½ billion years old.”

Herd cautions, though, that observing a meteoroid doesn’t mean it’s likely you’ll find a meteorite. Many simply evaporate on entry, while something that appears to be “just over there” could prove elusive.

“It’s easy to get caught up in the excitement, seeing something in the sky and then thinking you’ve found a meteorite. There are lots and lots of them. Have you come across the term ‘meteorwron­g’? That’s what they’re called.”

Herd remembers one such instance in the 1980s, when some people claimed to have discovered pieces of a meteorite.

“It was reported in the paper,” he recalls, “and then they brought it in to me, and what they had was the most incredible collection of chunks of asphalt.

“But they didn’t know. They were convinced, because there had been a bright light in the sky, and then they found something they thought hadn’t been there before.”

But first, a bit of nomenclatu­re: They’re only called meteorites after they’ve survived the fall through the Earth’s atmosphere and hit the surface of the planet. When they are streaks of bright light coursing overhead, they’re known as meteoroids.

And given that 70 per cent of the Earth’s surface is water, that’s where most meteorites fall, making confirmati­on difficult.

According to Herd, approximat­ely 67,500 known meteorites have struck the Earth, with about 43,000 of those landing in Antarctica, and a further 10,000 ending up in the Saharan and Arabian deserts. The remaining 14,500 were spread out around the rest of the planet.

Only slightly more than 70 confirmed meteorites have landed in Canada, a number that may seem low until you consider the country’s vast, often inaccessib­le, land mass and thin population density outside its southernmo­st cities. Of the meteorites confirmed to have landed between our shining seas, the closest to Ottawa was the Blithfield meteorite, a 1.83-kilogram rock discovered in August 1910 near Renfrew. Like most meteorites, it is classified as a “find,” meaning it was discovered some time after it hit Earth — anywhere from days to thousands of years — and was not connected to an observed meteoroid. Meteorites discovered subsequent to their observed fall to Earth are known as “falls.”

One of the largest and earliest meteorites found in Canada was the 167.5-kilogram Madoc meteorite discovered in 1854. Its discovery led to the creation of the National Meteorite Collection.

The largest confirmed meteorite in Canada was the 303-kilogram Bruderheim meteorite; more than 700 pieces of it were recovered following its March 4, 1960, fall in northern Alberta. The largest single piece weighed almost 30 kilograms.

While the chances of being struck by a meteorite are slim, it does happen. Studies have estimated that one person will be hit every seven to 14 years, with a fatality occurring roughly once every 52 years. In 1907, an entire family in China was reportedly killed by a meteorite that destroyed their house (although it’s unclear whether the meteorite actually struck any of the family members or if they were crushed by the collapsing house).

The best known (and perhaps only) confirmed case of a person being hit by a meteorite occurred in Sylacauga, Ala., in 1954, when Ann Hodges was hit by a softball-sized rock that crashed through the roof of her home, hit a radio, then struck her on her left thigh as she napped on her couch. The strike left a large, dark bruise.

In a 2013 story by National Geographic on the incident, Florida State College astronomer and meteorite expert Michael Reynolds remarked, “Think of how many people have lived throughout human history. You’d have a better chance of getting hit by a tornado and a bolt of lightning and a hurricane all at the same time.”

Perhaps the best-documented of all meteoroids/meteorites was the Peekskill meteorite, which entered the Earth’s atmosphere over Ohio on the evening of Oct. 9, 1992, its green fireball stretching for about 700 kilometres until a roughly 12-kilogram piece of it landed in Peekskill, N.Y., slamming through the trunk of a parked red 1980 Chevy Malibu that its owner, 18-year-old Michelle Knapp, had just purchased from her grandmothe­r for $400. (The lesson here, obviously, being never to buy a car from a family member.)

At least 16 video recordings captured the 4.4-billion-year-old meteoroid’s flight, as spectators at various football games along its path lifted their cameras to film the otherworld­ly visitor. From these, its orbit around the sun could be calculated, and its origin in the meteor belt between Jupiter and Mars determined.

“People want to study this stuff, because there’s a lot of informatio­n in it,” says Herd. “If you can figure out the key to unlocking it, there’s a lot of informatio­n in this material that’s coming in from outer space, and some of it could go back as far as the beginning of our universe. Certainly some of the elements do. So they’re valuable to study.”

 ?? WIKIPEDIA COMMONS ?? The Peekskill meteorite, which hit a car in Peekskill, N.Y., in 1992, is in the National Museum of Natural History.
WIKIPEDIA COMMONS The Peekskill meteorite, which hit a car in Peekskill, N.Y., in 1992, is in the National Museum of Natural History.

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