[meteorite-list] Canadian All-Sky Camera Doesn't Quite See All

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Sun, 18 Mar 2007 20:54:52 -0700 (PDT)
Message-ID: <200703190354.l2J3sqK22768_at_zagami.jpl.nasa.gov>

http://www.theglobeandmail.com/servlet/story/LAC.20070317.METEORITE17/TPStory/TPEntertainment/Ontario/

THE ALL-SKY CAMERA DOESN'T QUITE SEE ALL
BERT ARCHER
The Globe and Mail (Canada)
March 18, 2007

Judging from the radio call-in shows and hobbyist sites, lots of people
between cottage country and Wisconsin saw that meteor flash through last
Sunday's twilight sky. Everyone, that is, except the All-Sky Camera
Network, the largest meteorite detection system in eastern Canada and
the United States, with stations in Hamilton, London and Collingwood.

"Heh, yeah, you'd think we would have," says University of Western
Ontario's Professor Peter Brown. "This particular event just sort of
fell through the loop."

Between 8 and 8:30 Sunday evening, there was, in Prof. Brown's words,
"too much twilight" for the radar or the cameras to detect it. The
microphones, another part of this multi-instrumental system, also
happened to be down that night.

As a result, and unlike with the several other meteorites they do spot
every week, they have been unable to triangulate the approximate
location where this one touched down. ("Meteor" refers to the flaring,
falling rock, while "meteorite" describes any chunk that doesn't burn up
completely before touching down on earth.) However, based on the media
reports, Prof. Brown can make a guess.

"I think it's very likely the material made it to the ground, and it's
likely that the end point was somewhere around Detroit or western Lake
Erie," he says, adding, "I wouldn't be surprised if it ended up in the
lake."

Of those weekly detected night-sky flashes, there are "two or maybe
three a year that potentially produce small meteorites on the ground. In
the last two years, we've had about five in that category, and four of
the five went into Lake Huron," he says.

Only 69 meteorites have ever been found in Canada, and there have only
been about a dozen ever found anywhere that were "fresh falls" whose
trajectories had been recorded.

Given that, Prof. Brown pointed out that, for a variety of reasons,
fresh falls are extremely valuable, scientifically speaking. According
to the Prairie Meteorite Search, an organization Prof. Brown helped
establish and the only one of its kind in Canada, meteorites are often
found in spurts as a result of increased public awareness and interest
stemming from blips of media attention.

So how do you know if you've found a meteorite? If it's just fallen, it
tends to be imbedded in the dirt a little ways, and it has a black crust
on it, the result of the same atmospheric roasting that made it light
up. Meteorites are heavier than you might expect an Earth rock of the
same size to be, and they are almost all magnetic. Unfortunately,
according to Prof. Brown, they do not tend to glow or to smoke ominously.

So if you noticed a little black rock in your backyard that wasn't there
the night before, you might want to call Philip McCausland, UWO's
meteorite curator, at 519-661-2111, x. 87985; he'd be happy to talk to you.
Received on Sun 18 Mar 2007 11:54:52 PM PDT