Scientists from the University of Calgary have successfully found a number of meteorites from the spectacular fireball seen over western Canada on November 20th. The meteorites were found strewn over a many kilometer-wide area near the city of Lloydminster along the borders of Alberta and Saskatchewan. This spot is very close to the predicted fall area based on eyewitness reports and videos of the fireball.
A good story on the meteorite finds can be found at the Washington Post.
A more detailed and personal account of the meteorite hunt and finds was posted by Bruce McCurdy on the Meteorobs e-mail group.
Though the analysis is still preliminary, and might even be considered hearsay at this point, the meteorites appear to be a type of Ordinary Chondrite (OC). OCs are the most common type of meteorites seen to fall to Earth and are related to S-type asteroids. Though S-type asteroids are not the most common type of asteroid in space they are the dominant type in the inner half of the asteroid Main Belt between Mars and Jupiter. It is from this region of the asteroid Main Belt that the majority of the asteroids and meteoroids that cross the Earth’s orbit (and hence can impact the Earth) come from.
When the small asteroid that caused the fireball was traveling through space it was a single chunk of rock. Early estimates put its size and mass at up to a few meters across and up to 10 tons. During its quick trip through the Earth’s atmosphere, atmospheric and thermal (heat) forces broke the asteroid up into hundreds or thousands of pieces. Though much of its mass completely burnt up, enough of the remaining pieces survived to hit the ground to be found as meteorites.It is possible that there are thousands of meteorites to be found from this fireball.
Over the next few weeks or months analysis of the fireball’s orbit and the composition of the meteorites will be published. I will post further updates as more info is released.