By Thomas Miller Dr. Alan Hildebrand, an associate professor at
the University of Calgary, tracked the fireball that lit up the
sky in Lloydminster on Feb. 21. Hildebrand has been
investigating fireballs for nearly 20 years and is co-ordinator
of the Canadian Fireball Reporting Centre. He said what we saw
on Feb. 21 was an “exceptional case,” estimating the size of the
rock at more than 100 kilograms. “We would have about 100
meteorites fall in Canada each year,” said Hildebrand. “Even a
relatively small fireball could drop one meteorite. That one
Tuesday night is big enough that it probably dropped hundreds.
Something like it would happen somewhere on the earth, let’s say
once a week or so. “That’s just the way our solar system is made
– the number of asteroids we have in the asteroid belt, the rate
at which material leaks out into earth-crossing orbits, that
determines the frequency of these.” Hildebrand said the speed of
the rock, which was travelling at about 20 kilometres per second
in the air, produced