By Rhia Perkins
A University of Calgary Geology and Geophysics professor recently made some important discoveries about the nature of asteroids and comets with the help of meteorites found in northern British Columbia.
The meteorites, the largest fall in Canadian history, fell on Jan. 18 and were discovered on Jan. 25 by local resident Jim Brook near Tagish Lake.
"I was watching closely for meteorites and suspected their identity as soon as I saw them, although I had been fooled several times by wolf droppings," he said. "It was obvious what they were as soon as I picked one up because rocks aren’t found on the ice. I was very happy and excited."
Their icy landing is part of the reason this particular find is so important.
"Because it was found in a clean, cold environment and the finder kept it frozen, it may contain rare materials that are destroyed with heat," said Dr. Alan Hildebrand, U of C planetary scientist and co-leader of the meteorite recovery investigation. "It’s only the fifth time we have found a meteorite with enough information to discover its orbit and the first time one with a carbonaceous composition."
The meteorite fragments ranged in size, but the complete meteorite would have massed about 2.5 kg. Hildebrand hopes to use satellite data to establish the size of the fireball that produced the meteorite fragments.
"We’ll be better able to understand what the satellites are seeing and what the asteroids and comets are doing in their orbits," he said. "I think this will be a pretty good example of what we can do with satellite data. We may get a grant to take a group to visit big events like this around the world."
The composition of the meteorite is of extreme interest to the
scientific community. Carbonaceous meteorites represent about three per cent of falls worldwide, while the particular type of meteorite that landed in B.C. represents 0.01 per cent.
Although the chemical composition of the meteorite has not been analyzed in its entirety, it appears that it might represent a unique find.
"This is the find of a lifetime," said Peter Brown, meteor scientist at the University of Western Ontario and CO-leader of the investigation. "The size of the initial object, the extreme rarity and organic richness of the meteorites combined with the number we have uncovered make this a truly unique event."